(NewsTarget) Police in the British city of Plymouth have announced that affixing small digital cameras to the side of officers' helmets has drastically increased officers' ability to arrest and prosecute perpetrators of violent crime.
During the first 10 weeks of the pilot project, arrests for violent crime in the test area increased by 85 percent. This includes a 40 percent increase in the detection of such crimes and a 20 percent increase in the arrest and prosecution of suspects. Police also noted an 8 percent drop in the incidence of violent crime in the test area.
According to detective superintendent Richard Wood, head of a similar pilot program in London, the cameras' primary value is in making it easier for officers to prosecute those they observe committing crimes.
"Should anyone commit any offenses," he said, "the officers will instantly have the evidence to ... pursue criminal charges."
The small color cameras, similar in size to an AA battery are attached to the side of officers' helmets and record both audio and video footage of what is going on around them. The cameras being used in the London program, including a special utility belt to store the data, cost about £1,800 ($3,500) per officer.
The Plymouth trial involves approximately 250 officers wearing the cameras for six months and is scheduled to finish in March. Some of the video footage gathered in the first 10 weeks has been released to the public and is available online.
Both the Plymouth and London police departments hope to determine if the cameras would prove useful in other parts of the country.
These new surveillance programs are part of a wider effort in the United Kingdom to monitor citizens more effectively. London police are also experimenting with automated license plate recognition software, increased patrol visibility and airport-style weapons searches.
http://www.newstarget.com/021563.html
Saturday, May 19, 2007
Some analysts predict decline in digital camera sales
Highlight:
The price and complexity of digital cameras, combined with competition from cell phone cameras, have some analysts predicting sales for digital cameras will drop significantly by 2007. Christopher Chute, an analyst at IDC in Framingham, Mass. says digital camera companies aimed their product at affluent households, and never looked for the next segment of users. Chute estimates only 55 percent of American households will ever own a digital camera. Also, it was expected that digital cameras would kill film, but this is not the case, analysts say, largely due to digital's inability to live up to its promise of simplicity and economy. Some analysts disagree, however, saying a digital camera's ability to replace video cameras is fueling sales, and will continue to do so. These proponents also add that, while both digital cameras and camera phones race to increase the megapixel quality of their wares, the two products are more complementary than competitive, since camera phones often turn users on to digital cameras.
Original source:
http://www.startribune.com/stories/535/5426001.html
Summary:
* The prospect of digital cameras completely replacing their film counterparts, once taken for granted, may be fading fast.
* The price and complexity of digital cameras, and competition from cell-phone cameras, have some predicting that unit sales of digital cameras will begin to decline as soon as 2007 and that future digital camera purchases will be largely to replace existing models.
* The flaw in the digital-replaces-film scenario was the marketing campaigns waged by the digital camera manufacturers, Chute said.
* Still, when the dollar value of digital camera sales surpassed the sales of film cameras three years ago, the question was inevitably asked: Is film dead?
* Apparently not, and analysts point to several reasons why digital cameras haven't lived up to their initial promise.
* For starters, they are too difficult for many people to use, particularly when it comes to printing pictures.
* Digital cameras cost too much -- $140 to $947 last year, according to research firm IDC, with the average selling price $354.
* And stand-alone digital cameras face competition from improved cell-phone cameras that soon will offer 5-megapixel picture quality, up from today's 2 or 3 megapixels.
* "People walk into a Best Buy store every day with a camera memory card and say, 'What do I do with this?'
* Besides these two new approaches, manufacturers are continuing to ratchet up the megapixels in their stand-alone digital cameras in order to compete with the growing picture-taking quality of camera phones, even though analysts say that adding more megapixels won't help the average photographer.
* Camera phones are good for spur-of-the-moment shots but are limited in their ability to share photos because users typically must pay to use the cell-phone network in order to transmit photos to other wireless phones or to conventional e-mail addresses, Chute said.
See more articles and news on digital camera
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http://www.newstarget.com/005027.html
The price and complexity of digital cameras, combined with competition from cell phone cameras, have some analysts predicting sales for digital cameras will drop significantly by 2007. Christopher Chute, an analyst at IDC in Framingham, Mass. says digital camera companies aimed their product at affluent households, and never looked for the next segment of users. Chute estimates only 55 percent of American households will ever own a digital camera. Also, it was expected that digital cameras would kill film, but this is not the case, analysts say, largely due to digital's inability to live up to its promise of simplicity and economy. Some analysts disagree, however, saying a digital camera's ability to replace video cameras is fueling sales, and will continue to do so. These proponents also add that, while both digital cameras and camera phones race to increase the megapixel quality of their wares, the two products are more complementary than competitive, since camera phones often turn users on to digital cameras.
Original source:
http://www.startribune.com/stories/535/5426001.html
Summary:
* The prospect of digital cameras completely replacing their film counterparts, once taken for granted, may be fading fast.
* The price and complexity of digital cameras, and competition from cell-phone cameras, have some predicting that unit sales of digital cameras will begin to decline as soon as 2007 and that future digital camera purchases will be largely to replace existing models.
* The flaw in the digital-replaces-film scenario was the marketing campaigns waged by the digital camera manufacturers, Chute said.
* Still, when the dollar value of digital camera sales surpassed the sales of film cameras three years ago, the question was inevitably asked: Is film dead?
* Apparently not, and analysts point to several reasons why digital cameras haven't lived up to their initial promise.
* For starters, they are too difficult for many people to use, particularly when it comes to printing pictures.
* Digital cameras cost too much -- $140 to $947 last year, according to research firm IDC, with the average selling price $354.
* And stand-alone digital cameras face competition from improved cell-phone cameras that soon will offer 5-megapixel picture quality, up from today's 2 or 3 megapixels.
* "People walk into a Best Buy store every day with a camera memory card and say, 'What do I do with this?'
* Besides these two new approaches, manufacturers are continuing to ratchet up the megapixels in their stand-alone digital cameras in order to compete with the growing picture-taking quality of camera phones, even though analysts say that adding more megapixels won't help the average photographer.
* Camera phones are good for spur-of-the-moment shots but are limited in their ability to share photos because users typically must pay to use the cell-phone network in order to transmit photos to other wireless phones or to conventional e-mail addresses, Chute said.
See more articles and news on digital camera
Stay informed
Receive the NewsTarget Natural Health Newsletter for free!
* Stay informed on breaking news about natural health, renewable energy and more.
* 100% free of charge. Unsubscribe anytime.
* Absolutely no spam. We respect your privacy.
* Receive a free instant download of our $29 Secret Sources guide that reveals top sources for little-known health and diet solutions.
http://www.newstarget.com/005027.html
Friday, May 18, 2007
Digital cameras are good for the environment
As we consider the digital camera revolution that has taken place over the last decade, most people think about it in terms of enhanced benefits for consumers. We can take a lot more pictures at much lower cost with digital cameras versus film cameras. We can also more easily manipulate and share those photos since they're all in the digital realm.
But one thing many people don't think about actually deserves mention as potentially the most profound effect of the digital camera revolution: how digital cameras greatly reduce the destructive impact on the environment compared to film cameras.
At first, you might think, "How can that be? My film camera didn't harm the environment!" Even though it wasn't your camera that harmed the environment, your film processing did indeed harm it. Any time you take your pictures to a photo processing center, that film is run through batches of chemicals. These chemicals are environmental hazards, and once they are used to process film, those chemicals must be discarded. These chemicals include both developer solutions and fixer solutions.
All film photo processing centers use these chemicals. The question is, what do they do with these chemicals after they use them? According to environmental protection standards, they have to dispose of these chemicals in an environmentally sound way. That can mean trapping them in absorbent materials designed to render the chemicals inert and then disposing of those materials in a landfill. But more often than not, because of the increased expense involved in such endeavors, many film processing companies just pour the chemicals down the drain.
Don't believe me? Just ask anyone who has worked in a film processing company. While certainly the bigger and better known companies probably adhere to the environmental laws, many of the smaller, locally-owned companies don't. As an experiment, one day I went to a local film processing company and asked what they did with their chemicals after they were done using them. The answer? "We pour them down the drain!" And that means these chemicals enter the water supply and go downstream.
Quiz time: what do you get when you have 1,000 film developing companies and industrial chemical producers all breaking the rules and dumping chemicals into the river? You get the lower Mississippi river, which is of course a horrifying stream of man-made pollution that no one would want to swim in or drink... but yet provides the water for many of the cities downstream along the river (not to mention that the whole mess empties into the Gulf of Mexico, which is probably why the fish in the Gulf are too loaded with heavy metals to even consider eating...)
Another interesting angle on all of this is what happens in international waters, because cruise ships don't have to adhere to U.S. environmental protection standards. We already know that cruise ships dump raw sewage into the open ocean on a regular basis, but that's not even the worst part of it. They also dump film developing chemicals into the open ocean. This is done routinely: it's part of the regular process on world famous cruise lines. They develop your film for all the pictures you took on Aruba or the Cayman Islands or the Virgin Islands and then they pump the polluting chemicals to the ocean water. And we wonder why our oceans are dying and our coral reefs are dying at a rate faster than rainforest clear-cutting...
Back to digital cameras: it is pure coincidence, I think, that the upsurge in digital camera use is having a positive environmental impact. With digital photography, we no longer need to use all of those chemical solutions for developing photographs.
This is just one of many positive impacts of the digital camera revolution. But skeptical consumers might say "What about the environmental impact of all of the ink used in inkjet printers that people are printing their photos with?" And that's a reasonable question. The first part of that answer is that most of the photos taken with digital cameras stay in the digital domain (people don't print out all those photos).
As far as the inkjet ink chemistry goes, I'm willing to take an educated guess that there are solvents in those inks and those solvents should not be touched in their liquid form because they will absorbed through the skin and are probably carcinogenic. But once they dry, they're fairly safe to handle.
Regardless of the inkjet ink chemicals, the net effect of digital photography is undoubtedly positive from an environmental standpoint. Of course, most consumers don't even think about this. For most consumers, the digital camera argument is not about saving the planet, it's about getting the latest cool technology, or taking photos without the expense of physical film development. But whether or not the public really gives a hoot about the environment is beside the point in this particular case -- people are buying digital cameras in record numbers, the digital camera market continues to grow and film cameras are finally becoming obsolete. In my view, it couldn't be a moment too soon because a world without film cameras is, of course, a healthier world with fewer chemical contaminants.
One final thought: I do realize there's a potential negative impact to the environment related to the use of batteries in digital cameras. But most such batteries are rechargeable, so we're not talking about consumers chucking alkaline batteries into the landfill every week.
There's also the question of the environmental impact of manufacturing digital cameras. I'm sure that's not inconsequential, but it's probably similar to the impact of manufacturing film cameras anyway. And even high-end estimates of this manufacturing impact are relatively tame compared to the repeated destruction to the environment caused by film developer chemicals.
That's why I say the digital camera revolution is a net positive for the environment.
About the author:
Mike Adams is a natural health author and technology pioneer with a passion for sharing empowering information to help improve personal and planetary health He has authored more than 1,500 articles and dozens of reports, guides and interviews on natural health topics, impacting the lives of millions of readers around the world who are experiencing phenomenal health benefits from reading his articles. Adams is an independent journalist with strong ethics who does not get paid to write articles about any product or company. In 2007, Adams launched EcoLEDs, a manufacturer of mercury-free, energy-efficient LED lighting products that save electricity and help prevent global warming. He also launched an online retailer of environmentally-friendly products (BetterLifeGoods.com) and uses a portion of its profits to help fund non-profit endeavors. He's also a noted technology pioneer and founded a software company in 1993 that developed the HTML email newsletter software currently powering the NewsTarget subscriptions. Adams is currently the executive director of the Consumer Wellness Center, a 501(c)3 non-profit, and regularly pursues cycling, nature photography, Capoeira and Pilates. Known as the 'Health Ranger,' Adams' personal health statistics and mission statements are located at www.HealthRanger.org
But one thing many people don't think about actually deserves mention as potentially the most profound effect of the digital camera revolution: how digital cameras greatly reduce the destructive impact on the environment compared to film cameras.
At first, you might think, "How can that be? My film camera didn't harm the environment!" Even though it wasn't your camera that harmed the environment, your film processing did indeed harm it. Any time you take your pictures to a photo processing center, that film is run through batches of chemicals. These chemicals are environmental hazards, and once they are used to process film, those chemicals must be discarded. These chemicals include both developer solutions and fixer solutions.
All film photo processing centers use these chemicals. The question is, what do they do with these chemicals after they use them? According to environmental protection standards, they have to dispose of these chemicals in an environmentally sound way. That can mean trapping them in absorbent materials designed to render the chemicals inert and then disposing of those materials in a landfill. But more often than not, because of the increased expense involved in such endeavors, many film processing companies just pour the chemicals down the drain.
Don't believe me? Just ask anyone who has worked in a film processing company. While certainly the bigger and better known companies probably adhere to the environmental laws, many of the smaller, locally-owned companies don't. As an experiment, one day I went to a local film processing company and asked what they did with their chemicals after they were done using them. The answer? "We pour them down the drain!" And that means these chemicals enter the water supply and go downstream.
Quiz time: what do you get when you have 1,000 film developing companies and industrial chemical producers all breaking the rules and dumping chemicals into the river? You get the lower Mississippi river, which is of course a horrifying stream of man-made pollution that no one would want to swim in or drink... but yet provides the water for many of the cities downstream along the river (not to mention that the whole mess empties into the Gulf of Mexico, which is probably why the fish in the Gulf are too loaded with heavy metals to even consider eating...)
Another interesting angle on all of this is what happens in international waters, because cruise ships don't have to adhere to U.S. environmental protection standards. We already know that cruise ships dump raw sewage into the open ocean on a regular basis, but that's not even the worst part of it. They also dump film developing chemicals into the open ocean. This is done routinely: it's part of the regular process on world famous cruise lines. They develop your film for all the pictures you took on Aruba or the Cayman Islands or the Virgin Islands and then they pump the polluting chemicals to the ocean water. And we wonder why our oceans are dying and our coral reefs are dying at a rate faster than rainforest clear-cutting...
Back to digital cameras: it is pure coincidence, I think, that the upsurge in digital camera use is having a positive environmental impact. With digital photography, we no longer need to use all of those chemical solutions for developing photographs.
This is just one of many positive impacts of the digital camera revolution. But skeptical consumers might say "What about the environmental impact of all of the ink used in inkjet printers that people are printing their photos with?" And that's a reasonable question. The first part of that answer is that most of the photos taken with digital cameras stay in the digital domain (people don't print out all those photos).
As far as the inkjet ink chemistry goes, I'm willing to take an educated guess that there are solvents in those inks and those solvents should not be touched in their liquid form because they will absorbed through the skin and are probably carcinogenic. But once they dry, they're fairly safe to handle.
Regardless of the inkjet ink chemicals, the net effect of digital photography is undoubtedly positive from an environmental standpoint. Of course, most consumers don't even think about this. For most consumers, the digital camera argument is not about saving the planet, it's about getting the latest cool technology, or taking photos without the expense of physical film development. But whether or not the public really gives a hoot about the environment is beside the point in this particular case -- people are buying digital cameras in record numbers, the digital camera market continues to grow and film cameras are finally becoming obsolete. In my view, it couldn't be a moment too soon because a world without film cameras is, of course, a healthier world with fewer chemical contaminants.
One final thought: I do realize there's a potential negative impact to the environment related to the use of batteries in digital cameras. But most such batteries are rechargeable, so we're not talking about consumers chucking alkaline batteries into the landfill every week.
There's also the question of the environmental impact of manufacturing digital cameras. I'm sure that's not inconsequential, but it's probably similar to the impact of manufacturing film cameras anyway. And even high-end estimates of this manufacturing impact are relatively tame compared to the repeated destruction to the environment caused by film developer chemicals.
That's why I say the digital camera revolution is a net positive for the environment.
About the author:
Mike Adams is a natural health author and technology pioneer with a passion for sharing empowering information to help improve personal and planetary health He has authored more than 1,500 articles and dozens of reports, guides and interviews on natural health topics, impacting the lives of millions of readers around the world who are experiencing phenomenal health benefits from reading his articles. Adams is an independent journalist with strong ethics who does not get paid to write articles about any product or company. In 2007, Adams launched EcoLEDs, a manufacturer of mercury-free, energy-efficient LED lighting products that save electricity and help prevent global warming. He also launched an online retailer of environmentally-friendly products (BetterLifeGoods.com) and uses a portion of its profits to help fund non-profit endeavors. He's also a noted technology pioneer and founded a software company in 1993 that developed the HTML email newsletter software currently powering the NewsTarget subscriptions. Adams is currently the executive director of the Consumer Wellness Center, a 501(c)3 non-profit, and regularly pursues cycling, nature photography, Capoeira and Pilates. Known as the 'Health Ranger,' Adams' personal health statistics and mission statements are located at www.HealthRanger.org
Digital camera eye implant helps the blind see
(NewsTarget) If researchers at Glasgow University continue success in developing their prosthetic retina, blindness could become a thing of the past.
While more research and development is still needed, millions of people who have lost their sight may have hope of regaining it through a tiny eye implant that uses technology similar to that of a digital camera.
The 5mm device would work by translating light into electrical impulses and stimulating the retina, tricking the brain into believing it was receiving input from a working eye. Researchers say they are still five to 10 years away from a model that could be fitted to a human eye.
Dr. Keith Mathieson, leader of the Glasgow team, says, "The device would contain an imaging detector with hundreds of pixels coupled to an array of microscopic stimulating electrodes. If light forms an image on the detector, then the result will be electrical stimulation of the retina in the shape of this image. The stimulated cells then send the information via the optic nerve to the brain."
The prototype implant has 100 pixels, but the researchers hope that they will be able to increase this number over time. Mathieson said that 500 pixels would be sufficient for people to see where they are going and to recognize faces.
"We are trying to get to the point where someone would no longer need a guide dog, rather than replicate perfect vision," he said. He added that features such as action replay and slow motion could be included in the technology in the far future.
http://www.newstarget.com/019636.html
While more research and development is still needed, millions of people who have lost their sight may have hope of regaining it through a tiny eye implant that uses technology similar to that of a digital camera.
The 5mm device would work by translating light into electrical impulses and stimulating the retina, tricking the brain into believing it was receiving input from a working eye. Researchers say they are still five to 10 years away from a model that could be fitted to a human eye.
Dr. Keith Mathieson, leader of the Glasgow team, says, "The device would contain an imaging detector with hundreds of pixels coupled to an array of microscopic stimulating electrodes. If light forms an image on the detector, then the result will be electrical stimulation of the retina in the shape of this image. The stimulated cells then send the information via the optic nerve to the brain."
The prototype implant has 100 pixels, but the researchers hope that they will be able to increase this number over time. Mathieson said that 500 pixels would be sufficient for people to see where they are going and to recognize faces.
"We are trying to get to the point where someone would no longer need a guide dog, rather than replicate perfect vision," he said. He added that features such as action replay and slow motion could be included in the technology in the far future.
http://www.newstarget.com/019636.html
Too fat to be photographed? New HP digital camera slims photo subjects on the fly
(NewsTarget) Hewlett-Packard's Photosmart M and R series digital cameras include a "Slimming Mode" that makes any object or person centered in the photo look thinner, creating the illusion that a person is 10 - 20 pounds lighter. The feature was reportedly inspired by the number of people who told an HP survey that they hated having their picture taken. The Photosmart models can even take the compensation a step further with a mode that will virtually eliminate oversized pores and facial lines.
"We had a personal trainer wanting to use the camera as a motivational tactic for her clients," said Linda Kennedy, a product manager for digital photography at HP. She added that "putting a good photo of the person on their refrigerator so they can say, 'I do want to look like this,' as opposed to the fat picture in a bathing suit," can be inspiring.
Anthony Spina, an adjunct professor of sociology at Fairleigh Dickinson University in New Jersey feels that the slimming and skin tone tools are inspired by society's desire for physical perfection. He noted that they could also make for some interesting encounters were people to use them in online profiles.
"It almost does contribute to people changing their identities, for whatever reasons they are motivated to do that," Spina said. "Particularly, I can see it being used on a dating service. Now you can say the picture is current and still lie. But what I want to know is: What's going to finally happen when you meet that person? Even if you are not using it for that, its only interest is to make you look better. But why would you take a picture of yourself and give it to people who know you if it doesn't really look like you?
"This feature is a classic demonstration of American culture today, where illusion is deemed more important than reality," explained Mike Adams, a consumer health advocate and author of a popular weight loss book titled, Natural Appetite Suppressants for Safe, Effective Weight Loss. "Western culture is increasingly about the use of tricks, shortcuts and illusion to achieve an apparent outcome rather than the use of personal responsibility, healthy eating habits and good decision making," he said. "Too many consumers want to create the illusion of being physically fit without having to earn it."
Peter Southwick, associate professor and director of the photojournalism program at Boston University, worries that people's confidence in photographs will be shaken by these tools, having massive ramifications on both the legal and photojournalism worlds.
"People in the legal world are now concerned about whether photos can be accepted as evidence anymore, especially when you can alter the scene as you click the shutter," Southwick said. "And in the old days, there was an original, now there is no original. Photography as a tool for providing evidence, or as proof, may not exist anymore."
Southwick added that, while he was giving lectures in the past, he would ask how many people had heard of Photoshop, and 10 to 12 people would raise their hands. Now, he claims, everybody does. Southwick said that effect Photoshop has on the way people feel about photography's integrity will pale in comparison to the impact of in-camera photo-editing features.
"The consumer products and all these changes in photography, to me, are going to cause an undermining of people's ability to believe a photograph, which is the foundation of photojournalism," he said. "Now that it is at the consumer level and people are going to see this, I am not sure on a fundamental level that they are ever going to believe a photo when they see it."
http://www.newstarget.com/020246.html
"We had a personal trainer wanting to use the camera as a motivational tactic for her clients," said Linda Kennedy, a product manager for digital photography at HP. She added that "putting a good photo of the person on their refrigerator so they can say, 'I do want to look like this,' as opposed to the fat picture in a bathing suit," can be inspiring.
Anthony Spina, an adjunct professor of sociology at Fairleigh Dickinson University in New Jersey feels that the slimming and skin tone tools are inspired by society's desire for physical perfection. He noted that they could also make for some interesting encounters were people to use them in online profiles.
"It almost does contribute to people changing their identities, for whatever reasons they are motivated to do that," Spina said. "Particularly, I can see it being used on a dating service. Now you can say the picture is current and still lie. But what I want to know is: What's going to finally happen when you meet that person? Even if you are not using it for that, its only interest is to make you look better. But why would you take a picture of yourself and give it to people who know you if it doesn't really look like you?
"This feature is a classic demonstration of American culture today, where illusion is deemed more important than reality," explained Mike Adams, a consumer health advocate and author of a popular weight loss book titled, Natural Appetite Suppressants for Safe, Effective Weight Loss. "Western culture is increasingly about the use of tricks, shortcuts and illusion to achieve an apparent outcome rather than the use of personal responsibility, healthy eating habits and good decision making," he said. "Too many consumers want to create the illusion of being physically fit without having to earn it."
Peter Southwick, associate professor and director of the photojournalism program at Boston University, worries that people's confidence in photographs will be shaken by these tools, having massive ramifications on both the legal and photojournalism worlds.
"People in the legal world are now concerned about whether photos can be accepted as evidence anymore, especially when you can alter the scene as you click the shutter," Southwick said. "And in the old days, there was an original, now there is no original. Photography as a tool for providing evidence, or as proof, may not exist anymore."
Southwick added that, while he was giving lectures in the past, he would ask how many people had heard of Photoshop, and 10 to 12 people would raise their hands. Now, he claims, everybody does. Southwick said that effect Photoshop has on the way people feel about photography's integrity will pale in comparison to the impact of in-camera photo-editing features.
"The consumer products and all these changes in photography, to me, are going to cause an undermining of people's ability to believe a photograph, which is the foundation of photojournalism," he said. "Now that it is at the consumer level and people are going to see this, I am not sure on a fundamental level that they are ever going to believe a photo when they see it."
http://www.newstarget.com/020246.html
Thursday, May 17, 2007
Framed and Exposed: Digital Cameras, Raw Images, and Negative Standards
With the announcement of the Digital Negative Specification, Adobe is attempting to standardize how digital cameras understand image data. Will this new imaging initiative take off with camera makers? And what does it mean for you?
(creativepro.com)
By Ben Long, creativepro.com senior editor
Tuesday, October 12, 2004
View More In:
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Systems & Hardware
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Be the first to tell us what you think.
Respond to this article
For photographers who demand maximum control and superior image quality, one of the great appeals of digital is the ability to shoot in "raw" format. Unfortunately, because "raw" is an undefined format, rather than an accepted standard, you have to have software tailored to your particular camera to access a raw file. Adobe hopes to change all that with the release of its new Digital Negative Specification.
The Raw and the Cooked
As explained in my earlier column about camera sensors, a digital camera has to do a tremendous amount of processing and calculation to turn the data collected by its image sensor into a full-color image. Raw format allows you to save all of that original, unprocessed, uncompressed data directly to your camera's media card. Through the use of special software, you can use your computer to perform all of that gnarly image processing and calculation later and with much greater control.
With raw format, you can alter your image's white balance, exposure, sharpening, noise reduction and more after shooting, as well as perform all of your usual edits in a more flexible, accurate 16-bit color space.
The downside to shooting raw is time and workflow. To even look at a raw file, you must process it through a special raw format reader. Vendors are diligent about including their own special raw software with each camera that provides raw support, but it's astonishing to see how universally bad this software is, in terms of performance, interface, and integration with existing image-editing workflows.
Fortunately, several third-party vendors have stepped in to create more usable raw solutions. However, because camera vendors usually don't publish the details of their raw specs, software developers are often forced to reverse engineer the raw format of every camera they want to support. This is the main reason that you don't see raw support in more applications.
Raw-image workflow saw its biggest boost when Adobe released its Camera Raw plug-in for Photoshop 7 (Camera Raw is now built-in to Photoshop CS). With the ability to handle raw files directly in Photoshop, raw workflow was suddenly much simpler. In addition, Adobe's raw plug-in yielded very good results (raw image data is so raw, that there can be a tremendous amount of variation in the way different pieces of software choose to interpret it).
However, the problem of varying, unpublished raw formats remains, which means that when you buy the latest camera, you may not be able to open its raw files in any software, Photoshop included.
To address this issue, Adobe has developed and published an open standard that aims to make today's raw confusion a thing of the past.
Setting the Standard
Obviously, a lot of this confusion would pass if camera makers would simply agree on a single standard for raw format files. With the release of the Digital Negative Specification, Adobe has stepped forward and offered a standard that could, if adopted, tremendously ease the development of raw-compatible software.
Based on the TIFF-EP file format, the new DNG format is controlled and maintained by Adobe (just like TIFF) but is free to be used by any developer who wants to support it. In other words, only Adobe can make changes to the format, but anyone else is free to use it.
In addition to all of the normal TIFF tags, the new specification can hold all of the raw-related information that a program needs to correctly interpret a raw file. The new spec also provides tags for all of the usual EXIF information (camera settings, etc.) as well as support for all of the same XMP metadata supported by the Adobe Creative Suite applications.
Most proprietary raw formats also include what Adobe refers to as "special sauce" information that is necessary to correctly interpret certain raw data. To facilitate this data, the DNG specification allows for camera vendors to create special "private" metadata that only they can use.
With the announcement of the spec, Adobe also released a free upgrade to the existing Camera Raw plug-in, which provides support for a slew of new cameras. In addition, they released a DNG Converter application that can convert raw files from any of the currently supported raw formats into the new DNG specification.
Who Cares? I Care!
On paper this all sounds great, but the actual benefit to end users is dependent on who ends up adopting and supporting the new format.
Right now, the only compelling reason to convert your raw images to DNG is paranoia. If you're afraid that the multi-national corporate giant that manufactured your camera might one day go out of business, leaving you with no software to read your library of extant raw files, then switching to this new open standard is probably a reasonable thing to do. Even if Adobe ever goes under, the fact that the standard is freely published means someone will probably continue to provide software that's compatible with it.
Adobe is currently recommending that you save all of your original raw files, even if you convert to DNG. Because there is still undocumented private metadata in your original files, you'll want to have them around for maximum compatibility.
In testing the Digital Negative Converter with raw files from a Canon EOS 20D, it took my 1-GHz G4 PowerBook about 5 seconds per image to convert from Canon's CR2 format to the new DNG format. The resulting files were a little smaller -- down anywhere from 500 k to 1 GB. In other words, if you want to switch to DNG now, you'll have to devote some time to processing your images, and you're gonna need twice the storage that you're using now.
The real advantage to the end user will come from vendor support of the format. Because cracking a camera raw format is time consuming, few applications provide direct support for it. In theory, Adobe's published standard should make it much easier for any software developer to add raw support -- and not have to update it every time a camera is released -- meaning that your imaging workflow could one day be much more flexible.
The ideal future, of course, would be a camera that writes directly to DNG format. Obviously, this is what Adobe wants, not because they necessarily stand to make money from the adoption of their standard, but because they don't want to have to keep supporting new raw formats.
Whether vendors will go for this remains to be seen. At the time of this writing, none of the camera vendors we talked to were ready to make a statement about their DNG opinions.
What Now?
In theory, there are tremendous advantages to camera vendors: They don't have to develop, test, and maintain their own raw format; they get instant compatibility with Photoshop and any other app that supports DNG format; Adobe's support for "private" metadata means they don't have to give up on any of their own proprietary designs.
In the end, Adobe could choose to play hardball. If the new spec gains some momentum in the form of adoption by a majority of camera vendors, Adobe could simply stop providing support for proprietary raw formats, meaning that any camera that doesn't support DNG is locked out of the Photoshop raw workflow. For the serious photographer, this might be reason enough to choose a different camera.
Until more vendors -- software and hardware -- support it, DNG will remain just a promise of improved workflow. As a photographer, you probably don't need to concern yourself with the format yet, but it's worth keeping an eye on its development.
http://www.creativepro.com/story/feature/22023.html
(creativepro.com)
By Ben Long, creativepro.com senior editor
Tuesday, October 12, 2004
View More In:
Graphics
Systems & Hardware
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For photographers who demand maximum control and superior image quality, one of the great appeals of digital is the ability to shoot in "raw" format. Unfortunately, because "raw" is an undefined format, rather than an accepted standard, you have to have software tailored to your particular camera to access a raw file. Adobe hopes to change all that with the release of its new Digital Negative Specification.
The Raw and the Cooked
As explained in my earlier column about camera sensors, a digital camera has to do a tremendous amount of processing and calculation to turn the data collected by its image sensor into a full-color image. Raw format allows you to save all of that original, unprocessed, uncompressed data directly to your camera's media card. Through the use of special software, you can use your computer to perform all of that gnarly image processing and calculation later and with much greater control.
With raw format, you can alter your image's white balance, exposure, sharpening, noise reduction and more after shooting, as well as perform all of your usual edits in a more flexible, accurate 16-bit color space.
The downside to shooting raw is time and workflow. To even look at a raw file, you must process it through a special raw format reader. Vendors are diligent about including their own special raw software with each camera that provides raw support, but it's astonishing to see how universally bad this software is, in terms of performance, interface, and integration with existing image-editing workflows.
Fortunately, several third-party vendors have stepped in to create more usable raw solutions. However, because camera vendors usually don't publish the details of their raw specs, software developers are often forced to reverse engineer the raw format of every camera they want to support. This is the main reason that you don't see raw support in more applications.
Raw-image workflow saw its biggest boost when Adobe released its Camera Raw plug-in for Photoshop 7 (Camera Raw is now built-in to Photoshop CS). With the ability to handle raw files directly in Photoshop, raw workflow was suddenly much simpler. In addition, Adobe's raw plug-in yielded very good results (raw image data is so raw, that there can be a tremendous amount of variation in the way different pieces of software choose to interpret it).
However, the problem of varying, unpublished raw formats remains, which means that when you buy the latest camera, you may not be able to open its raw files in any software, Photoshop included.
To address this issue, Adobe has developed and published an open standard that aims to make today's raw confusion a thing of the past.
Setting the Standard
Obviously, a lot of this confusion would pass if camera makers would simply agree on a single standard for raw format files. With the release of the Digital Negative Specification, Adobe has stepped forward and offered a standard that could, if adopted, tremendously ease the development of raw-compatible software.
Based on the TIFF-EP file format, the new DNG format is controlled and maintained by Adobe (just like TIFF) but is free to be used by any developer who wants to support it. In other words, only Adobe can make changes to the format, but anyone else is free to use it.
In addition to all of the normal TIFF tags, the new specification can hold all of the raw-related information that a program needs to correctly interpret a raw file. The new spec also provides tags for all of the usual EXIF information (camera settings, etc.) as well as support for all of the same XMP metadata supported by the Adobe Creative Suite applications.
Most proprietary raw formats also include what Adobe refers to as "special sauce" information that is necessary to correctly interpret certain raw data. To facilitate this data, the DNG specification allows for camera vendors to create special "private" metadata that only they can use.
With the announcement of the spec, Adobe also released a free upgrade to the existing Camera Raw plug-in, which provides support for a slew of new cameras. In addition, they released a DNG Converter application that can convert raw files from any of the currently supported raw formats into the new DNG specification.
Who Cares? I Care!
On paper this all sounds great, but the actual benefit to end users is dependent on who ends up adopting and supporting the new format.
Right now, the only compelling reason to convert your raw images to DNG is paranoia. If you're afraid that the multi-national corporate giant that manufactured your camera might one day go out of business, leaving you with no software to read your library of extant raw files, then switching to this new open standard is probably a reasonable thing to do. Even if Adobe ever goes under, the fact that the standard is freely published means someone will probably continue to provide software that's compatible with it.
Adobe is currently recommending that you save all of your original raw files, even if you convert to DNG. Because there is still undocumented private metadata in your original files, you'll want to have them around for maximum compatibility.
In testing the Digital Negative Converter with raw files from a Canon EOS 20D, it took my 1-GHz G4 PowerBook about 5 seconds per image to convert from Canon's CR2 format to the new DNG format. The resulting files were a little smaller -- down anywhere from 500 k to 1 GB. In other words, if you want to switch to DNG now, you'll have to devote some time to processing your images, and you're gonna need twice the storage that you're using now.
The real advantage to the end user will come from vendor support of the format. Because cracking a camera raw format is time consuming, few applications provide direct support for it. In theory, Adobe's published standard should make it much easier for any software developer to add raw support -- and not have to update it every time a camera is released -- meaning that your imaging workflow could one day be much more flexible.
The ideal future, of course, would be a camera that writes directly to DNG format. Obviously, this is what Adobe wants, not because they necessarily stand to make money from the adoption of their standard, but because they don't want to have to keep supporting new raw formats.
Whether vendors will go for this remains to be seen. At the time of this writing, none of the camera vendors we talked to were ready to make a statement about their DNG opinions.
What Now?
In theory, there are tremendous advantages to camera vendors: They don't have to develop, test, and maintain their own raw format; they get instant compatibility with Photoshop and any other app that supports DNG format; Adobe's support for "private" metadata means they don't have to give up on any of their own proprietary designs.
In the end, Adobe could choose to play hardball. If the new spec gains some momentum in the form of adoption by a majority of camera vendors, Adobe could simply stop providing support for proprietary raw formats, meaning that any camera that doesn't support DNG is locked out of the Photoshop raw workflow. For the serious photographer, this might be reason enough to choose a different camera.
Until more vendors -- software and hardware -- support it, DNG will remain just a promise of improved workflow. As a photographer, you probably don't need to concern yourself with the format yet, but it's worth keeping an eye on its development.
http://www.creativepro.com/story/feature/22023.html
Framed and Exposed: Buying a Digital Camera, Part 6
This is it: The final installment of Ben Long's guide to selecting a digital camera model. We're down to the pivotal issue of image quality. Here's how to evaluate cameras for color, noise, and other image essentials.
Over the last five installments of this column, you have been presented with a barrage of questions and options related to choosing a digital camera. If you've been following along, you've asked yourself what type of shooting you do, what features you think you want, what you need in terms of size and weight. After answering all of these questions, you should have narrowed down the field of possible candidates to just a handful of cameras. You're now at the very last stage: the final choice.
The good news is that making the final choice may not be too hard, because, in the end, one single question should outweigh all others when selecting a camera: How good are the images it produces? The bad news is that, if you're already favoring a particular camera for its features and design, you may have to nix it and go with a secondary camera that yields better image quality.
Image quality is, of course, a very subjective topic -- one person's hideous noise might be another's beautiful texture. Nevertheless, with a little bit of attention, you can identify problems up front that might vex you later.
In this final "Choosing a camera" installment, we're going to quickly take a look at the most common image-quality issues that you should consider when choosing a camera. In addition to aiding your camera choice, learning to identify these problems now can help in your image-editing efforts later.
Print or Monitor?
Before you can begin comparing image quality, you've gotta have some images to evaluate. A camera LCD is not good enough to evaluate image quality, because color and contrast are rarely accurate on a camera LCD. Camera screens are not intended for accurate output, and they're designed to be visible in very bright sunlight, which means that vendors often have to increase brightness and contrast to improve image quality.
So, if you want to evaluate image quality from a particular camera, you need to get some images out of the camera and back to your computer at home. The easiest way to do this is to buy a memory card that you can take to the camera store. You can then fill it up with images that you can look at back at home. If you're considering cameras that use different formats, then you might need to invest in several cards, but media is cheap right now and you don't need high-capacity cards for these kinds of tests.
Laptop owners have the option of taking their computer to the store and loading images in directly from the camera.
Finally, there are a number of camera review sites that regularly post full-resolution output from their review camera units. These are perfectly suited to evaluation, and usually cover a much greater range of lighting and shooting conditions than you could ever find in a typical camera store.
Obviously, your first evaluations will be performed on your computer monitor, and there's much that you can learn from these assessments. However, when viewing images onscreen, it's also possible to get hung up on issues that may not be a problem in your final output. Simply put: When you can zoom in to look at the individual pixels of an 8-megapixel image, you're likely to find some troublesome artifacts. Whether these artifacts will be visible in an 8-x-10-inch glossy is another question.
So, when evaluating an image, lend a little thought to what your final output will be. If you mostly shoot for the Web, or on-screen viewing, then consider the typical size that you use, and do a round of evaluations at that size.
If you predominantly take images for print, then you'll need a round of evaluation using your typical printing technology, media, and print sizes. Many troubles and artifacts that are visible onscreen may vanish when resized and output using a particular printing technology.
Noise Levels
Though there are a lot of things that can go wrong with an image, the issue you're most likely to notice first when comparing cameras is noise. Noise is roughly analogous to grain in a piece of film and, like grain, it's not necessarily a bad thing, as it can add texture and atmosphere to an image.
However, sometimes digital-camera noise has a more intrusive character than film grain, manifesting as speckly colored patterns rather than an underlying texture. What's more, there will be times when you don't want to have any noise in your images. Because noise can easily be added using an image-editing program, it's better to get a camera with very low noise, so that you'll have the choice of producing clean or noisy images.
The good news is that, these days, most cameras have their noise issues under control. What's more, on a higher-res camera, noise is typically much finer, meaning it will often vanish if you downsize the image.
Noise is almost always more prominent in the shadow parts of an image, and this is the first place to go looking when evaluating an image.
There are two types of noise: chrominance noise and luminance noise. Luminance noise is the preferable of the two, as it looks more like film grain. Where luminance noise is simply a variation in the brightness of the pixels in the image, chrominance noise is a variation in the color -- sometimes an extreme variation. If you see brightly colored blue, red, or even purple pixels, then your camera is exhibiting chrominance noise (see Figure 1).
Again, noise is not a problem that has to be completely avoided, but it's good to know the noise characteristics of a particular camera.
Noise gets worse as you increase the camera's ISO settings, so you'll want to do noise tests across the camera's ISO range. Because ISO is a valuable exposure parameter, you'll want to carefully consider noise levels at higher ISOs. If possible, you might also want to try evaluating some long-exposure images, as noise also increases with exposure time.
Color Troubles
Color reproduction is probably the most subjective of all image quality considerations. What you think of as beautiful, saturated color, someone else might perceive to be garish, velvet-Elvis-painting color. Neither is wrong, of course, so in the end you need to base your consideration on the color you like. As with noise, though, it's still a good idea to know if a particular camera has certain color tendencies. Some color issues to be aware of include:
* Color casts. Some cameras have a tendency to produce images with a particular cast -- an overall color tone that makes the image appear as if it were shot through a colored filter of some kind. Sometimes, the cast will only affect a particular part of the image -- perhaps shadows are too blue, for example.
* Bad white balance. Just as you must select a film that's appropriate for the light you're shooting in, your camera must calibrate its idea of color according to the current light. This process, called white balancing, can sometimes go awry, resulting in images with out-of-whack color. A bad white balance is similar to a color cast, except that white balance problems usually affect the entire color range, not just the shadows or highlights. White balance prowess is something you want to be very conscious of, as removing a bad white balance can be difficult, if not impossible. Most cameras offer a choice of automatic and manual white balances. Because you'll most often use automatic white balance, you'll want to closely evaluate images shot in auto white balance mode.
* Chromatic aberration. All cameras, including film cameras are subject to this weird type of artifact that's sometimes referred to as "purple fringing" (see Figure 2). Sometimes, chromatic aberration is caused by poor lens optics; at other times it's the result of pixels on the camera's image sensor essentially overflowing with light and corrupting neighboring pixels. Chromatic aberrations usually only occur when shooting high-contrast subjects in bright light -- you'll often see it appear along the edges of leaves against a bright sky -- and even then usually only at extreme focal lengths. Chromatic aberration that's readily apparent on-screen is often invisible in print, and it's usually not too difficult to remove, if need be.
* Inaccurate color. This one's a tricky one, because a camera can sometimes yield colors that are dead wrong, but that still look great -- maybe even better than the original. What's more, they might do this consistently. Some cameras, for example, pump up the saturation in an image to produce a "glossy" result. This process can boost the colors into the realm of "wrong" yet yield a more pleasing image. If you're a stickler for accuracy, then you're going to want to evaluate color with this in mind. If you simply want consistently attractive images that require little editing, then accuracy may not be as important.
In the Details
The amount of sharpness and detail in an image is the result of several camera factors: How much resolution your camera has, how good your lens is, and how good your camera's built-in sharpening routines are.
The tricky thing about assessing detail is that you may not know that there's detail missing. In other words, you may think the image looks fine simply because you're not aware of what's there.
The figure below shows the same scene shot with the same camera - a Canon EOS 10D - but using two different lenses (see figure 3). Though neither image looks bad, there's a marked difference in detail.
The easiest way to assess detail when comparing cameras is to examine identical images side-by-side. For this kind of testing, you'll want to go to your camera store and shoot the same scene with all of your candidate cameras. Even if all you can manage is a shot of the cash register, this should still be enough to give you an idea of the differences in detail and sharpness between the different models.
Because in-camera sharpening can greatly affect the quality of an image -- sometimes for the better, sometimes for the worse -- you'll want to take some images with varying degrees of sharpening applied.
Although you may think that more sharpness is inherently better, it is possible to oversharpen an image. To evaluate a camera's sharpening mechanism, look for bright and dark halos around high-contrast areas in an image.
Bad Exposure
You'll use your camera's automatic metering for almost all of your images, so you'll want to get a sense of how well it exposes in difficult lighting situations. Again, sample pictures downloadable from camera review Web sites should ease this problem. Pay particular attention to how well the camera meters in low light, in complex mixed lighting situations (lots of bright and dark in the scene), when shooting with flash, as well as overall consistency of metering.
Most cameras these days have very good light meters, and a skilled photographer can compensate for most difficult metering situations.
Some cameras exhibit lens distortions when shooting at the extreme wide or telephoto ends of their focal ranges. Though these problems are rarely deal-breakers, and can be corrected in post-production, it's worth keeping an eye out for them when evaluating image quality.
Finally, since JPEG compression can seriously degrade the quality of an image, look for JPEG artifacts -- regular, square blocky patterns throughout an image -- when shooting at the camera's highest quality level.
Conclusion
As discussed in the first installment of "Framed and Exposed," most modern digital cameras yield very good images. There are differences, and some might be more to your taste than others, but the good news is that your image evaluations should not be too trying, because you're probably going to see nice results from most cameras.
When considering the image quality issues discussed here, remember to factor in price. Yes, you may not be seeing images that are as good as what your friend gets from his $1,500 digital SLR, but if you're only aiming to spend $500, then you should expect to take a hit in image quality. For this reason, when comparing image quality, be sure to compare comparable cameras. Don't get hung up on how your candidate cameras compare to models that you can't afford.
http://www.creativepro.com/story/feature/21955.html
Over the last five installments of this column, you have been presented with a barrage of questions and options related to choosing a digital camera. If you've been following along, you've asked yourself what type of shooting you do, what features you think you want, what you need in terms of size and weight. After answering all of these questions, you should have narrowed down the field of possible candidates to just a handful of cameras. You're now at the very last stage: the final choice.
The good news is that making the final choice may not be too hard, because, in the end, one single question should outweigh all others when selecting a camera: How good are the images it produces? The bad news is that, if you're already favoring a particular camera for its features and design, you may have to nix it and go with a secondary camera that yields better image quality.
Image quality is, of course, a very subjective topic -- one person's hideous noise might be another's beautiful texture. Nevertheless, with a little bit of attention, you can identify problems up front that might vex you later.
In this final "Choosing a camera" installment, we're going to quickly take a look at the most common image-quality issues that you should consider when choosing a camera. In addition to aiding your camera choice, learning to identify these problems now can help in your image-editing efforts later.
Print or Monitor?
Before you can begin comparing image quality, you've gotta have some images to evaluate. A camera LCD is not good enough to evaluate image quality, because color and contrast are rarely accurate on a camera LCD. Camera screens are not intended for accurate output, and they're designed to be visible in very bright sunlight, which means that vendors often have to increase brightness and contrast to improve image quality.
So, if you want to evaluate image quality from a particular camera, you need to get some images out of the camera and back to your computer at home. The easiest way to do this is to buy a memory card that you can take to the camera store. You can then fill it up with images that you can look at back at home. If you're considering cameras that use different formats, then you might need to invest in several cards, but media is cheap right now and you don't need high-capacity cards for these kinds of tests.
Laptop owners have the option of taking their computer to the store and loading images in directly from the camera.
Finally, there are a number of camera review sites that regularly post full-resolution output from their review camera units. These are perfectly suited to evaluation, and usually cover a much greater range of lighting and shooting conditions than you could ever find in a typical camera store.
Obviously, your first evaluations will be performed on your computer monitor, and there's much that you can learn from these assessments. However, when viewing images onscreen, it's also possible to get hung up on issues that may not be a problem in your final output. Simply put: When you can zoom in to look at the individual pixels of an 8-megapixel image, you're likely to find some troublesome artifacts. Whether these artifacts will be visible in an 8-x-10-inch glossy is another question.
So, when evaluating an image, lend a little thought to what your final output will be. If you mostly shoot for the Web, or on-screen viewing, then consider the typical size that you use, and do a round of evaluations at that size.
If you predominantly take images for print, then you'll need a round of evaluation using your typical printing technology, media, and print sizes. Many troubles and artifacts that are visible onscreen may vanish when resized and output using a particular printing technology.
Noise Levels
Though there are a lot of things that can go wrong with an image, the issue you're most likely to notice first when comparing cameras is noise. Noise is roughly analogous to grain in a piece of film and, like grain, it's not necessarily a bad thing, as it can add texture and atmosphere to an image.
However, sometimes digital-camera noise has a more intrusive character than film grain, manifesting as speckly colored patterns rather than an underlying texture. What's more, there will be times when you don't want to have any noise in your images. Because noise can easily be added using an image-editing program, it's better to get a camera with very low noise, so that you'll have the choice of producing clean or noisy images.
The good news is that, these days, most cameras have their noise issues under control. What's more, on a higher-res camera, noise is typically much finer, meaning it will often vanish if you downsize the image.
Noise is almost always more prominent in the shadow parts of an image, and this is the first place to go looking when evaluating an image.
There are two types of noise: chrominance noise and luminance noise. Luminance noise is the preferable of the two, as it looks more like film grain. Where luminance noise is simply a variation in the brightness of the pixels in the image, chrominance noise is a variation in the color -- sometimes an extreme variation. If you see brightly colored blue, red, or even purple pixels, then your camera is exhibiting chrominance noise (see Figure 1).
Again, noise is not a problem that has to be completely avoided, but it's good to know the noise characteristics of a particular camera.
Noise gets worse as you increase the camera's ISO settings, so you'll want to do noise tests across the camera's ISO range. Because ISO is a valuable exposure parameter, you'll want to carefully consider noise levels at higher ISOs. If possible, you might also want to try evaluating some long-exposure images, as noise also increases with exposure time.
Color Troubles
Color reproduction is probably the most subjective of all image quality considerations. What you think of as beautiful, saturated color, someone else might perceive to be garish, velvet-Elvis-painting color. Neither is wrong, of course, so in the end you need to base your consideration on the color you like. As with noise, though, it's still a good idea to know if a particular camera has certain color tendencies. Some color issues to be aware of include:
* Color casts. Some cameras have a tendency to produce images with a particular cast -- an overall color tone that makes the image appear as if it were shot through a colored filter of some kind. Sometimes, the cast will only affect a particular part of the image -- perhaps shadows are too blue, for example.
* Bad white balance. Just as you must select a film that's appropriate for the light you're shooting in, your camera must calibrate its idea of color according to the current light. This process, called white balancing, can sometimes go awry, resulting in images with out-of-whack color. A bad white balance is similar to a color cast, except that white balance problems usually affect the entire color range, not just the shadows or highlights. White balance prowess is something you want to be very conscious of, as removing a bad white balance can be difficult, if not impossible. Most cameras offer a choice of automatic and manual white balances. Because you'll most often use automatic white balance, you'll want to closely evaluate images shot in auto white balance mode.
* Chromatic aberration. All cameras, including film cameras are subject to this weird type of artifact that's sometimes referred to as "purple fringing" (see Figure 2). Sometimes, chromatic aberration is caused by poor lens optics; at other times it's the result of pixels on the camera's image sensor essentially overflowing with light and corrupting neighboring pixels. Chromatic aberrations usually only occur when shooting high-contrast subjects in bright light -- you'll often see it appear along the edges of leaves against a bright sky -- and even then usually only at extreme focal lengths. Chromatic aberration that's readily apparent on-screen is often invisible in print, and it's usually not too difficult to remove, if need be.
* Inaccurate color. This one's a tricky one, because a camera can sometimes yield colors that are dead wrong, but that still look great -- maybe even better than the original. What's more, they might do this consistently. Some cameras, for example, pump up the saturation in an image to produce a "glossy" result. This process can boost the colors into the realm of "wrong" yet yield a more pleasing image. If you're a stickler for accuracy, then you're going to want to evaluate color with this in mind. If you simply want consistently attractive images that require little editing, then accuracy may not be as important.
In the Details
The amount of sharpness and detail in an image is the result of several camera factors: How much resolution your camera has, how good your lens is, and how good your camera's built-in sharpening routines are.
The tricky thing about assessing detail is that you may not know that there's detail missing. In other words, you may think the image looks fine simply because you're not aware of what's there.
The figure below shows the same scene shot with the same camera - a Canon EOS 10D - but using two different lenses (see figure 3). Though neither image looks bad, there's a marked difference in detail.
The easiest way to assess detail when comparing cameras is to examine identical images side-by-side. For this kind of testing, you'll want to go to your camera store and shoot the same scene with all of your candidate cameras. Even if all you can manage is a shot of the cash register, this should still be enough to give you an idea of the differences in detail and sharpness between the different models.
Because in-camera sharpening can greatly affect the quality of an image -- sometimes for the better, sometimes for the worse -- you'll want to take some images with varying degrees of sharpening applied.
Although you may think that more sharpness is inherently better, it is possible to oversharpen an image. To evaluate a camera's sharpening mechanism, look for bright and dark halos around high-contrast areas in an image.
Bad Exposure
You'll use your camera's automatic metering for almost all of your images, so you'll want to get a sense of how well it exposes in difficult lighting situations. Again, sample pictures downloadable from camera review Web sites should ease this problem. Pay particular attention to how well the camera meters in low light, in complex mixed lighting situations (lots of bright and dark in the scene), when shooting with flash, as well as overall consistency of metering.
Most cameras these days have very good light meters, and a skilled photographer can compensate for most difficult metering situations.
Some cameras exhibit lens distortions when shooting at the extreme wide or telephoto ends of their focal ranges. Though these problems are rarely deal-breakers, and can be corrected in post-production, it's worth keeping an eye out for them when evaluating image quality.
Finally, since JPEG compression can seriously degrade the quality of an image, look for JPEG artifacts -- regular, square blocky patterns throughout an image -- when shooting at the camera's highest quality level.
Conclusion
As discussed in the first installment of "Framed and Exposed," most modern digital cameras yield very good images. There are differences, and some might be more to your taste than others, but the good news is that your image evaluations should not be too trying, because you're probably going to see nice results from most cameras.
When considering the image quality issues discussed here, remember to factor in price. Yes, you may not be seeing images that are as good as what your friend gets from his $1,500 digital SLR, but if you're only aiming to spend $500, then you should expect to take a hit in image quality. For this reason, when comparing image quality, be sure to compare comparable cameras. Don't get hung up on how your candidate cameras compare to models that you can't afford.
http://www.creativepro.com/story/feature/21955.html
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