Digital cameras have tossed many novices into the deep end of the photographic pool, with the result that learning how to shoot good pictures has been a sink-or-swim affair. Few have grounded their digital knowledge in traditional film basics, like lens length and light metering. It's time to catch up.
Remember the early days of desktop publishing, when graphic design novices suddenly found themselves (either by choice or assignment) taking on layout and design jobs? Digital technology is having a similar effect on photography.
Because of the low cost and extreme convenience of digital photography, many people are being cast in the role of photographer when it comes time to update the company Web site or newsletter, or take some simple product shots. Granted, in an ideal world, these jobs should be going to a professional photographer. But in many cases it's not a question of "Should we have a professional photographer shoot this? Or Bob in marketing?" It's a question of "Should we have Bob in marketing take a picture of this? Or just go without?" With digital photography so convenient and inexpensive, many people are choosing to use photos where they wouldn't have before.
Outside the workplace, people with no previous photography experience are picking up digital cameras and finding them very compelling. Browse through any of the popular photoblogging sites on the Net, and you'll find lots of entries from people who comment "I'd never really taken any pictures before I got my digital camera," and now they're posting photos-- in some cases, extremely good photos.
Because of the automatic features and ease-of-use of the modern digital camera (and point-and-shoot film camera) it's easy to pick up a digital camera and take decent pictures without having to learn some of the important, basic concepts that older technology forced beginning photographers to learn. I answer a lot of questions about digital photography, and I'm frequently surprised to find that people who are taking very good digital photos often have some very conspicuous gaps in their basic photographic knowledge. Similarly, I also encounter a lot of people who are being asked to assume a photographic mantle at work, even though they have little more than snapshot experience.
Over the next two installments of this column, we're going to look at some of the basic photographic concepts and principles that experienced film photographers take for granted, but that the digital photographer, might never have learned. These principles should help you get better results from your camera, and perhaps help you better understand the creative possibilities at your disposal.
Choosing a Focal Length
These days, almost all digital cameras come with zoom lenses. We're talking about actual optical zoom lenses, not digital zoom features. The great thing about a zoom lens is that, for small cameras with fixed lenses, a zoom gives you a choice of focal lengths, while for cameras with interchangeable lenses, they enable you to carry less gear.
Inexperienced photographers, though, don't necessarily know that a zoom lens is not just a way to get closer to a distant subject. (Even experienced photographers can become lazy and choose to zoom when they should move themselves instead.) In addition to allowing you to gain a telephoto view of a distant object, your zoom lens provides you with a rather profound control of the sense of space in your scene. Zooming can also -- intentionally or not -- create some rather weird distortions of your subject.
The basics: Shorter focal lengths yield a wider field of view while longer focal lengths ("telephoto") yield a narrower field of view
Your eye sees roughly a 55-60-degree field of view, so lenses that are shorter than 50mm are considered wide-angle, while lenses that are longer than 50mm are considered telephoto. (These lengths are in 35mm equivalency. If you're not clear on this concept, see part three of my opus on buying a digital camera.)
But when you zoom, there's a lot more going on than just a change of field of view and magnification.
As focal length increases, so does depth compression. In other words, longer lenses compress the sense of depth in your image, causing the apparent distance between your foreground and background to shrink.
In both cases, our subject is framed identically, but the backgrounds of the images are very different. In the wide-angle shot, the café tables appear to be much farther away than in the telephoto shot, and our subject is actually obscuring some background details, such as the FedEx truck on the next block. In the telephoto image, the tables seem closer, and the entire block appears shorter and more intimate.
As this example demonstrates, your choice of focal length can have a profound impact on the sense of space in your scene. So, though it may be more convenient to say "I want to take a picture of that thing over there, I'll just zoom in to it" you might want to consider whether a very telephoto focal length will yield an atmosphere that's appropriate to the venue or to the feeling you're trying to evoke.
Obviously, if a telephoto lens compresses depth, a wider-angle lens stretches depth. When we speak of changes in depth, we mean all depth, not just big foreground/background changes. This is important to remember when shooting portraits.
If you've ever seen a picture of yourself and thought "that really doesn't look like me" one reason might be that the photographer used a lens that was too short. notice that, just as in our street scene, the sense of depth is greatly reduced, while in Figure 4a, the sense of depth has been stretched so that the man's ears appear much farther back, his nose seems longer, his eyes spaced different.
Portrait photographers typically use a slightly telephoto lens, so to achieve the same sort of effect, you'll want to stand a little farther away from your subject and zoom in.
Of course, there are times when you might want to use this distortion to your advantage. For example, the wide-angle shot in Figure 3 might be more evocative of the subject's true character than the telephoto shot.
Or, maybe you're shooting an image that is supposed to be slightly whimsical. Next time you watch a comedy at the movies, pay attention to how often wide angle lenses are used. Similarly, note that people in whimsical print ads are usually distorted in the wide-angle way shown above.
To sum up: Your zoom lens is not just a convenience to help you take pictures of things that are far away. The ability to zoom in does not come "for free." As you zoom in and out, the composition of your image changes drastically, so you need to think about camera position and focal length very carefully when setting up your shot.
Striving for Adequacy
Most people assume that the automatic light meter in their camera calculates the best possible exposure for a scene, and in most cases this is true. However, there are times when your light meter will merely do an adequate job. Understanding some light meter fundamentals will help.
The goal of a light meter is to calculate a shutter speed and aperture value (and, in some digital cameras, an ISO speed) that will yield a good image. Light meters vary in their approach to solving this problem. Simple systems take basic luminance measurements, while high-end meters measure brightness from many parts of the image, and compare this information to a database of correctly exposed images to come up with a proper exposure.
In general, though, you should remember the following two things about your light meter: It knows nothing about color, and it assumes that you're pointing it at a scene that is 18% gray.
If that last item seems a little arbitrary, you're just going to have to take it on faith. The fact is: Most scenes reflect about 18% of the light that strikes them, meaning that if the camera assumes it's looking at a scene that's 18% gray, and calculates an exposure accordingly, then that exposure is probably going to be valid for your particular scene.
Since most scenes truly are 18% gray, then your meter's assumption is usually valid. However, if you're standing in a field of snow, taking a picture of an albino in a white parka who's listening to an iPod, then your light meter's fundamental assumption is going to be wrong. The result will be an image of an ashen figure wearing a dirty parka while listening to an unidentifiable MP3 player, because the light meter will have correctly calculated a reading that renders the scene as gray.
Similarly, if you're shooting a Johnny Cash impersonator standing on a lava flow holding a bowling ball, then following your light meter's suggestion is going to result in the tones in your image being rendered as gray rather than black.
For these instances, you'll need to out-think your light meter and over- or under-expose to render tones correctly. Over-expose to render white objects white, under-expose to darken black objects The easiest way to do this is with your camera's exposure compensation controls, though you can also use any manual exposure modes that your camera might have.
Colors also have a luminance value. A deep red color, for example, might have a luminance value that is darker than 18% gray and so will be rendered more accurately and more richly with an underexposure.
One of the great advantages of digital over film is expense (or lack thereof). If you're not sure whether you need to over- or under-expose, then bracket your shots. Shoot one at the meter's recommendation, then some additional frames over- and under. Many cameras offer auto-bracketing features that , when combined with the camera's burst or drive mode, will automatically shoot a series of bracketed shots. Later, you can examine the images to decide which yields the most accurate exposure for your subject.
Nothing New
The concerns presented here are nothing that photographers haven't always faced. However, with a digital camera, it's easy to shoot pictures without learning these concepts ahead of time. Hopefully, understanding these concerns a little better will help you to shoot better pictures.
http://www.creativepro.com/story/feature/22087.html
Thursday, May 3, 2007
Framed and Exposed: Better Image Automation Through Scripting
Managing your images can be a tedious time-consuming task. But learning how to harness the power of AppleScript and Image Events can make quick work of renaming, resizing, and rotating your images, along with other essential duties.
Whether you run a complex Web or print production workflow, or you're a professionalphotographer who needs to manage 1,000-image shoots, or you're a hobbyist photographer drowning in media, workflow automation can be an essential concern for achieving your end goal -- whether it be a Web site, magazine, or simple high-quality print. Digital photography workflow and workflow automation will be a subject that we will return to repeatedly in this column, but this week we're looking at the digital photography applications of the AppleScript language that's built into the Mac OS and, specifically, the image processing routines that are built into OS X 10.3.
AppleScript was introduced with version 7 of the OS, way back in the early '90s, and Apple wisely migrated the technology to OS X. AppleScript is a scripting language with all of the elements and structures that you would expect of a modern programming language. There's nothing particularly special about AppleScript as a programming language -- in fact, there are a lot of things about AppleScript that are really annoying. What makes AppleScript so useful and powerful are Apple Events -- messages and commands that can be sent from application to application, and which you can control through the use of AppleScript.
An application must have Apple Events support built-in before you can control it with Applescript, but these days almost all major graphics and design applications are scriptable, as are the Macintosh OS and Finder.
AppleScript Basics
A quick summary for those of you who've never fiddled with AppleScript before: AppleScript is part of the standard OS installation and so is available on any Mac. In your Applications > AppleScript folder you'll find a copy of ScriptEditor, a simple application for writing and compiling scripts.
Along with the development of AppleScript, Apple created the Open Scripting Architecture (OSA), an open standard that allows other vendors to create languages that can control and respond to Apple Events. Script Editor lets you write and compile scripts for any OSA-compliant language. So, for example, if you'd rather create your automation scripts using JavaScript, you can install a special OSA version of JavaScript. We'll look more at AppleScript alternatives (which can be ideal for mixed Mac/Windows environments) in a future column.
In addition to saving simple scripts that can be run from a script editing application like ScriptEditor, AppleScript allows you to create standalone, double-clickable applications, droplet applications, or scripts that can be attached to folders or other applications.
The AppleScript language itself is somewhat similar to Apple's old HyperTalk language (the native language of HyperCard) and follows a similar English-like syntax. This is both a blessing and a hindrance. Its English-like feel is less intimidating to beginning scripters, but the vagaries of English grammar -- as well as the existence of so many synonymous terms -- means it can be difficult to remember the precise AppleScript syntax that you need for a particular command.
Here's a sample AppleScript script that shows a typical automation routine. This script (called PhotoRenamer, which you can download from my Web site) creates a droplet, an application that processes any files dropped on top of it. Digital cameras, of course, produce files with rather useless, meaningless names. When you drop a folder on top of this droplet, it builds a new filename for each file inside. The resulting files will be named _..
http://www.creativepro.com/story/feature/22342.html
Whether you run a complex Web or print production workflow, or you're a professionalphotographer who needs to manage 1,000-image shoots, or you're a hobbyist photographer drowning in media, workflow automation can be an essential concern for achieving your end goal -- whether it be a Web site, magazine, or simple high-quality print. Digital photography workflow and workflow automation will be a subject that we will return to repeatedly in this column, but this week we're looking at the digital photography applications of the AppleScript language that's built into the Mac OS and, specifically, the image processing routines that are built into OS X 10.3.
AppleScript was introduced with version 7 of the OS, way back in the early '90s, and Apple wisely migrated the technology to OS X. AppleScript is a scripting language with all of the elements and structures that you would expect of a modern programming language. There's nothing particularly special about AppleScript as a programming language -- in fact, there are a lot of things about AppleScript that are really annoying. What makes AppleScript so useful and powerful are Apple Events -- messages and commands that can be sent from application to application, and which you can control through the use of AppleScript.
An application must have Apple Events support built-in before you can control it with Applescript, but these days almost all major graphics and design applications are scriptable, as are the Macintosh OS and Finder.
AppleScript Basics
A quick summary for those of you who've never fiddled with AppleScript before: AppleScript is part of the standard OS installation and so is available on any Mac. In your Applications > AppleScript folder you'll find a copy of ScriptEditor, a simple application for writing and compiling scripts.
Along with the development of AppleScript, Apple created the Open Scripting Architecture (OSA), an open standard that allows other vendors to create languages that can control and respond to Apple Events. Script Editor lets you write and compile scripts for any OSA-compliant language. So, for example, if you'd rather create your automation scripts using JavaScript, you can install a special OSA version of JavaScript. We'll look more at AppleScript alternatives (which can be ideal for mixed Mac/Windows environments) in a future column.
In addition to saving simple scripts that can be run from a script editing application like ScriptEditor, AppleScript allows you to create standalone, double-clickable applications, droplet applications, or scripts that can be attached to folders or other applications.
The AppleScript language itself is somewhat similar to Apple's old HyperTalk language (the native language of HyperCard) and follows a similar English-like syntax. This is both a blessing and a hindrance. Its English-like feel is less intimidating to beginning scripters, but the vagaries of English grammar -- as well as the existence of so many synonymous terms -- means it can be difficult to remember the precise AppleScript syntax that you need for a particular command.
Here's a sample AppleScript script that shows a typical automation routine. This script (called PhotoRenamer, which you can download from my Web site) creates a droplet, an application that processes any files dropped on top of it. Digital cameras, of course, produce files with rather useless, meaningless names. When you drop a folder on top of this droplet, it builds a new filename for each file inside. The resulting files will be named
Framed and Exposed: Balancing the Lens and Sensor Equation
Small lenses are casting a wide angle on digital photo market. Ben Long takes a look at the advancing technology and what Canon is up to with the EF-S 10-22mm lens
The semi-pro/pro digital camera market is divided fairly cleanly, right now, along a very simple
line: sensor size. Yes, resolution is also a factor, with hardcore pros using SLRs with high-res 12 to 14 megapixel image sensors, while serious hobbyists and less-moneyed pros are using 6-8 megapixel SLRs, but the coveted "full-frame sensor" is the mark of a true high-end digital professional.
What's the big deal with sensor size? First and foremost, of course, is image quality. Though less-expensive, smaller-sensored cameras like the Canon EOS 20D and the Nikon D70 offer excellent image quality and high-end features, but they use an image sensor that's roughly the same size as a piece of APS film. High-end, pro cameras that pack more pixels, such as the Canon 1DS Mark II use an image sensor that's the same size as a piece of 35mm film.
This difference in physical size has a tremendous bearing on image quality. Obviously, more pixels can be crammed onto the bigger sensor, but more importantly, the pixels themselves are larger than what you'll find on a smaller sensor. Larger pixel size means better signal-to-noise ratio, which means images with better color, less noise, and potentially better detail, sharpness, and low-light performance.
There's another significant advantage to a 35mm sensor, though, and that has to do with lenses. Because these cameras are designed to work with lens systems that were developed for 35mm film sizes, using the same lenses with a smaller sensor means that your image gets cropped in a way that effectively changes the field of view of the lens. So, if you stick a 50mm lens on a Canon 20D, it gives you the same field of view as an 80mm lens on a 35mm camera, or on a full-frame digital camera.
Though this focal length multiplier is a boon to people who want telephoto lenses, for wide-angle shooters it presents a serious drawback. Stick a 28mm lens on your 20D and you're stuck with an almost "normal" 44mm lens.
Obviously, high-end pro cameras - which can cost upwards of $6000 more than their smaller-sensored brethren - pack other "pro" features such as faster shooting rate, weather proofing, finer control of image processing, better light meters, and so on.
In the end, though, it's the sensor size - and its effect on image quality and focal length - that separates the high-end digital pros from those who can't justify $10K on a digital camera system.
Same sensor, different lens
Some vendors argue that there are other drawbacks to the current "let's stick a smaller sensor in a body engineered for 35mm film" strategy. Olympus has completely eschewed this approach in favor of developing a completely new body/lens system. According to Olympus, compatibility with 35mm lens systems has an inherent disadvantage because, basically, it's a hack. They claim that a more sensible approach is to design a camera/lens combo with a particular sensor in mind. To that end, they support the 4/3 Consortium that specifies sensor sizes and shapes. Though Olympus' theory is interesting, they have yet to produce a digital SLR with interchangeable lenses that proves their advantage.
Canon has taken a different approach. With the release of the Digital Rebel, a camera that packs an APS-sized sensor, Canon introduced a new lens mount, the EF-S.
Canon recognized that, with the smaller sensor size, you can get away with a smaller mirror and pentaprism system, which means you can free up some space inside the camera's body. With this extra space to exploit, it's possible to build lenses with rear elements that protrude farther into the camera. The EF-S lens mount, while fully supporting Canon's entire line of EF and L lenses, also supports the mounting of special S lenses, with these deeper rear elements. (The "S" actually stands for "short back focus.")
This new mount accomplishes two things. First, it allowed Canon to design a mount that's more appropriate for the APS-sized sensor used in the Rebel, 20D, and any other "mid-range" SLRs they choose to produce. In theory, this should answer the claims of those who find cramming a small sensor into an existing 35mm lens system to be somehow nauseating. More importantly, it allows for the creation of smaller, less expensive lenses without sacrificing quality.
When engineering a lens, it's optically advantageous to have the lens as close to the focal plane as possible. As you position the lens closer to the image sensor, the lens itself can become physically smaller. What's more, it's much easier to engineer a lens that can focus onto a small area than a large area. Since EF-S lenses only have to cover an APS-sized area, eliminating aberrations and flares is much easier than with a lens that has to cover a 35mm-sized area.
This is one reason that tiny point-and-shoot cameras deliver such good images. Their sensors are tiny, so it's easy to engineer a good lens for them. The EF-S lens system allows Canon to exploit the small sensor advantage of an APS-sized sensor. With easier lens engineering, extremely wide-angle lenses (a type of lens that is usually difficult to engineer and therefore very expensive) are suddenly easier, and therefore cheaper, to build.
Such is the case with Canon's new 10-22mm EF-S lens, a $799 (list) lens for the Canon Digital Rebel and EOS 20D. With a 35mm equivalency of 16-35mm, this lens effectively answers the "but how can I shoot wide angle with an APS-sized image sensor" problem that has been frustrating many digital photographers.
The lens itself is excellent, and you can read a full review of it here, but the lens is also interesting for what it implies about the digital SLR market.
How much would you pay? Well don't answer!
Many pro and semi-pro digital photographers have been waiting for full-frame digital SLRs to come down in price. The attitude is that the current generation of cameras is a somewhat "stop-gap" measure, while we wait for full-frame sensors to become cheap enough for everyone to afford. So, the idea goes, it shouldn't be too long before we have full-frame digital SLRs at the $1500 price point.
Given the rapid progress of digital SLR development, in terms of resolution, performance, and improvements in image quality, this isn't an entirely unreasonable assumption. After all, we're all used to Moore's law cropping up in all digital devices, so it should only be another year or so before we have the equivalent of a Canon 1DS Mark II 14-megapixel full-frame camera for under $2000, right?
Canon's 10-22mm lens makes this assumption less certain. When Canon released the Digital Rebel, they also released two EF-S lenses. Then the 20D came along, the Rebel's slightly bigger brother with a $1500 price tag. One of the core improvements that the 20D had over its predecessor, the 10D, was support for EF-S lenses. With the 20D came the announcement of 2 new EF-S lenses, the 17-85 IS and the 10-22mm.
In other words, with the 20D came the assertion that the S lens system is something Canon is taking seriously. In addition to expanding the system across their mid-range market, they've proven that they're taking active steps to shore up the lens selection for their new mount, offering an image stabilized "walk-around" lens, and a lens that provides an excellent solution to the problem of shooting wide-angle on small-sensor digital SLRs.
So, those photographers who've been holding out for a full-frame sensor camera to appear at the current price point of something like the 20D, might have a very long wait ahead of them.
With the EF-S mount and current selection of lenses, Canon has answered the problem of how to shoot wide angle with an affordable digital SLR. They've also addressed the claims of those who believe lenses should be engineered for a particular sensor size. Since Canon's excellent L-series lenses work fine on the Rebel and 20D, the S lenses serve to shore up the more difficult wide end. In other words, Canon has done everything they need to do to assure a full range of high-quality lenses for their mid-range cameras.
That's not the attitude of a company that's aiming to shift everyone toward full-frame digital cameras.
With the D30, Canon invented the "affordable" digital SLR market. (Granted, that camera was $3000, but that price was significantly lower than the $5000 SLR that Nikon was offering.) From there, they moved very quickly to push the SLR entry price down to $2000, then $1500, and finally with the Rebel, $899.
At the same time, they did an excellent job of building a high-end line-up. It seems obvious that their goal has not been to push everyone toward full-frame pro cameras, but to develop and exploit the obviously large mid-range market.
Selling cameras is great, but the real money is in lenses, and now Canon has three separate lines of lenses that they can market to very specific, vertical niches. That's a great position to be in.
What's more, there's no reason for them to eliminate this market. Just because we always shot film of a particular size doesn't mean we need to use digital sensors of that size. Canon and Nikon have proven that you can get excellent, perfectly usable images from an APS-sized sensor, and with Canon smartly addressing the lens selection question, the drive toward full-frame seems far less pressing.
From this perspective, it's obvious that the sensor-size line that separates high-end pros from everyone else is here to stay. Yes, there will be improvements in both areas, but the market will remain thusly delineated.
So, if you've been putting off going digital, or moving to a digital SLR, because you're hoping for an affordable full frame camera, look again. You may not need full frame, and the big camera companies may not want to sell you one at the price you're hoping to pay.
http://www.creativepro.com/story/feature/22468.html
The semi-pro/pro digital camera market is divided fairly cleanly, right now, along a very simple
line: sensor size. Yes, resolution is also a factor, with hardcore pros using SLRs with high-res 12 to 14 megapixel image sensors, while serious hobbyists and less-moneyed pros are using 6-8 megapixel SLRs, but the coveted "full-frame sensor" is the mark of a true high-end digital professional.
What's the big deal with sensor size? First and foremost, of course, is image quality. Though less-expensive, smaller-sensored cameras like the Canon EOS 20D and the Nikon D70 offer excellent image quality and high-end features, but they use an image sensor that's roughly the same size as a piece of APS film. High-end, pro cameras that pack more pixels, such as the Canon 1DS Mark II use an image sensor that's the same size as a piece of 35mm film.
This difference in physical size has a tremendous bearing on image quality. Obviously, more pixels can be crammed onto the bigger sensor, but more importantly, the pixels themselves are larger than what you'll find on a smaller sensor. Larger pixel size means better signal-to-noise ratio, which means images with better color, less noise, and potentially better detail, sharpness, and low-light performance.
There's another significant advantage to a 35mm sensor, though, and that has to do with lenses. Because these cameras are designed to work with lens systems that were developed for 35mm film sizes, using the same lenses with a smaller sensor means that your image gets cropped in a way that effectively changes the field of view of the lens. So, if you stick a 50mm lens on a Canon 20D, it gives you the same field of view as an 80mm lens on a 35mm camera, or on a full-frame digital camera.
Though this focal length multiplier is a boon to people who want telephoto lenses, for wide-angle shooters it presents a serious drawback. Stick a 28mm lens on your 20D and you're stuck with an almost "normal" 44mm lens.
Obviously, high-end pro cameras - which can cost upwards of $6000 more than their smaller-sensored brethren - pack other "pro" features such as faster shooting rate, weather proofing, finer control of image processing, better light meters, and so on.
In the end, though, it's the sensor size - and its effect on image quality and focal length - that separates the high-end digital pros from those who can't justify $10K on a digital camera system.
Same sensor, different lens
Some vendors argue that there are other drawbacks to the current "let's stick a smaller sensor in a body engineered for 35mm film" strategy. Olympus has completely eschewed this approach in favor of developing a completely new body/lens system. According to Olympus, compatibility with 35mm lens systems has an inherent disadvantage because, basically, it's a hack. They claim that a more sensible approach is to design a camera/lens combo with a particular sensor in mind. To that end, they support the 4/3 Consortium that specifies sensor sizes and shapes. Though Olympus' theory is interesting, they have yet to produce a digital SLR with interchangeable lenses that proves their advantage.
Canon has taken a different approach. With the release of the Digital Rebel, a camera that packs an APS-sized sensor, Canon introduced a new lens mount, the EF-S.
Canon recognized that, with the smaller sensor size, you can get away with a smaller mirror and pentaprism system, which means you can free up some space inside the camera's body. With this extra space to exploit, it's possible to build lenses with rear elements that protrude farther into the camera. The EF-S lens mount, while fully supporting Canon's entire line of EF and L lenses, also supports the mounting of special S lenses, with these deeper rear elements. (The "S" actually stands for "short back focus.")
This new mount accomplishes two things. First, it allowed Canon to design a mount that's more appropriate for the APS-sized sensor used in the Rebel, 20D, and any other "mid-range" SLRs they choose to produce. In theory, this should answer the claims of those who find cramming a small sensor into an existing 35mm lens system to be somehow nauseating. More importantly, it allows for the creation of smaller, less expensive lenses without sacrificing quality.
When engineering a lens, it's optically advantageous to have the lens as close to the focal plane as possible. As you position the lens closer to the image sensor, the lens itself can become physically smaller. What's more, it's much easier to engineer a lens that can focus onto a small area than a large area. Since EF-S lenses only have to cover an APS-sized area, eliminating aberrations and flares is much easier than with a lens that has to cover a 35mm-sized area.
This is one reason that tiny point-and-shoot cameras deliver such good images. Their sensors are tiny, so it's easy to engineer a good lens for them. The EF-S lens system allows Canon to exploit the small sensor advantage of an APS-sized sensor. With easier lens engineering, extremely wide-angle lenses (a type of lens that is usually difficult to engineer and therefore very expensive) are suddenly easier, and therefore cheaper, to build.
Such is the case with Canon's new 10-22mm EF-S lens, a $799 (list) lens for the Canon Digital Rebel and EOS 20D. With a 35mm equivalency of 16-35mm, this lens effectively answers the "but how can I shoot wide angle with an APS-sized image sensor" problem that has been frustrating many digital photographers.
The lens itself is excellent, and you can read a full review of it here, but the lens is also interesting for what it implies about the digital SLR market.
How much would you pay? Well don't answer!
Many pro and semi-pro digital photographers have been waiting for full-frame digital SLRs to come down in price. The attitude is that the current generation of cameras is a somewhat "stop-gap" measure, while we wait for full-frame sensors to become cheap enough for everyone to afford. So, the idea goes, it shouldn't be too long before we have full-frame digital SLRs at the $1500 price point.
Given the rapid progress of digital SLR development, in terms of resolution, performance, and improvements in image quality, this isn't an entirely unreasonable assumption. After all, we're all used to Moore's law cropping up in all digital devices, so it should only be another year or so before we have the equivalent of a Canon 1DS Mark II 14-megapixel full-frame camera for under $2000, right?
Canon's 10-22mm lens makes this assumption less certain. When Canon released the Digital Rebel, they also released two EF-S lenses. Then the 20D came along, the Rebel's slightly bigger brother with a $1500 price tag. One of the core improvements that the 20D had over its predecessor, the 10D, was support for EF-S lenses. With the 20D came the announcement of 2 new EF-S lenses, the 17-85 IS and the 10-22mm.
In other words, with the 20D came the assertion that the S lens system is something Canon is taking seriously. In addition to expanding the system across their mid-range market, they've proven that they're taking active steps to shore up the lens selection for their new mount, offering an image stabilized "walk-around" lens, and a lens that provides an excellent solution to the problem of shooting wide-angle on small-sensor digital SLRs.
So, those photographers who've been holding out for a full-frame sensor camera to appear at the current price point of something like the 20D, might have a very long wait ahead of them.
With the EF-S mount and current selection of lenses, Canon has answered the problem of how to shoot wide angle with an affordable digital SLR. They've also addressed the claims of those who believe lenses should be engineered for a particular sensor size. Since Canon's excellent L-series lenses work fine on the Rebel and 20D, the S lenses serve to shore up the more difficult wide end. In other words, Canon has done everything they need to do to assure a full range of high-quality lenses for their mid-range cameras.
That's not the attitude of a company that's aiming to shift everyone toward full-frame digital cameras.
With the D30, Canon invented the "affordable" digital SLR market. (Granted, that camera was $3000, but that price was significantly lower than the $5000 SLR that Nikon was offering.) From there, they moved very quickly to push the SLR entry price down to $2000, then $1500, and finally with the Rebel, $899.
At the same time, they did an excellent job of building a high-end line-up. It seems obvious that their goal has not been to push everyone toward full-frame pro cameras, but to develop and exploit the obviously large mid-range market.
Selling cameras is great, but the real money is in lenses, and now Canon has three separate lines of lenses that they can market to very specific, vertical niches. That's a great position to be in.
What's more, there's no reason for them to eliminate this market. Just because we always shot film of a particular size doesn't mean we need to use digital sensors of that size. Canon and Nikon have proven that you can get excellent, perfectly usable images from an APS-sized sensor, and with Canon smartly addressing the lens selection question, the drive toward full-frame seems far less pressing.
From this perspective, it's obvious that the sensor-size line that separates high-end pros from everyone else is here to stay. Yes, there will be improvements in both areas, but the market will remain thusly delineated.
So, if you've been putting off going digital, or moving to a digital SLR, because you're hoping for an affordable full frame camera, look again. You may not need full frame, and the big camera companies may not want to sell you one at the price you're hoping to pay.
http://www.creativepro.com/story/feature/22468.html
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