Thursday, July 5, 2007

Photography 101 Series

I just bought a new digital camera! I see that my new digital delight can take images in several different formats. There's JPEG mode, TIFF mode, or even a mode called RAW. Is one better than the other? What differences will I see in the final images between the three formats? Which will it be, JPEG, TIFF, or RAW?

The type of photography YOU do weighs heavily on which mode you use. And, you may want to use ALL the formats at one time or another. Since your camera is flexible enough to shoot in multiple formats, you shouldn't be afraid to test them all. There are pros and cons for each of them, and we'll consider each below:

JPEG Mode

The great majority of photographers use the JPEG image as their primary image capture mode. This is mainly for the following reasons:

* Maximum number of images on camera and computer hard drive storage.
* Fastest writes from camera memory buffer to memory card storage.
* Absolute compatibility with everything and everybody in imaging.
* High-quality first use images.
* No special software needed to use the image right out of the camera. (No post-processing)
* Immediate use on websites with minimal processing.
* Easy transfer across Internet, and as e-mail attachments.

If you use JPEG as your primary image mode, just be aware of these facts.

* JPEG is a "lossy" format, which means that it permanently throws away image data from compression algorithm losses as you select higher levels of compression.
* You cannot use JPEG to manipulate an image more than once or twice before it degrades to an unusable state.
* Every time you modify and resave a JPEG image, it loses more data.
* May not be as sharp out of the camera as TIFF or RAW modes, due to initial camera compression.

Other than that, a JPEG image is capable of making marvelous images. The initial image out of the camera is considerably smaller in file size, and yet still yields an excellent image for web use or printing. You simply cannot take the image and modify it over and over again for special effects without the image becoming unusable. Many photographers work within this knowledge, and shoot exclusively JPEG images.

TIFF Mode

Many other photographers select the TIFF image mode of their cameras for primary usage. The list of reasons to select this mode are:

* Very high image quality.
* Excellent compatibility with the publishing industry.
* Is considered a "lossless" format, since the image normally uses no compression, and loses no more data than the initial conversion from 12-bit to 8-bit in the camera's software.
* Can modify and resave the images an endless number of times without throwing away image data.
* Does not require software post-processing during or after download from camera, so the image is immediately usable.

The drawbacks to using the TIFF imaging mode are as follows:

* Very large files in camera memory, so your ability to take a lot of images requires large and expensive storage cards.
* Must have large hard drives on your computer to store these multi-megabyte images.
* In-camera image processing is significantly slower, so you will be limited in the number of fast pictures you can take.
* Unless you have a high-speed Internet connection, don't even consider sending one of these monsters across the Internet. My D100 in RGB-TIFF Large Mode generates a 17.6 megabyte file.

RAW Mode

Camera purists, large print aficionados, and weird website article writers prefer this mode above all others. Here's why:

* Allows the manipulation of image data to achieve the highest quality image available from the camera.
* All original detail stays in the image for future processing needs.
* No conversions, sharpening, sizing, or color rebalancing will be performed by the camera. Your images are untouched and pure!
* Can convert to any of the above formats by using your computer's much more powerful processor instead of the camera processor.
* You have MUCH more control over the final look of the image, since YOU, not the camera are making decisions as to the final appearance of the image.
* 12-bit format for maximum image data.

The drawbacks to using RAW mode are these:

* Not compatible with publishing industry, except by conversion to another format.
* Requires pre-processing by special proprietary software as provided by the camera manufacturer or third-party software programmers. (This is generally included with the camera.)
* Large file sizes, so you must have large storage media. (Although, not as large as TIFF)
* No accepted industry standard RAW mode. Each camera manufacturer has their own proprietary format. Adobe® has recently introduced a new RAW format called DNG (Digital Negative) that may become a industry standard. We'll see!
* 12-bit format not really in use as of yet, since 8-bit is industry standard.

Which do I prefer? Why, RAW, of course. But, it does require a bit of a commitment to shoot in this mode. The camera is simply an image capturing device, and YOU are the image manipulator. You decide the final format, compression ratios, sizes, color balances, etc. In RAW mode, you have the absolute best image your camera can produce. It is unoptimized, and ready for your personal touch. No camera processing allowed!

If you get nothing else from this article, remember this...by letting your camera process the images in ANY way, it is modifying or throwing away image data. There is only a finite amount of data for each image that can be stored on your camera, and later on the computer. With JPEG or TIFF mode, your camera is optimizing the image according to the assumptions recorded in its memory. Data is being thrown away permanently, in varying amounts.

If you want to keep ALL the image data that was recorded in the image, you must store your originals in RAW format. Otherwise you will never again be able to access that original data to change how it looks. RAW format is the closest thing to a film negative or a transparency that your digital camera can make.

That is important if you would like to use the image later for modification. If you are a photographer that is concerned with maximum quality you should probably use RAW mode, and store your images in RAW format. Later, when you have the urge to make another masterpiece out of the original RAW image file, you will have ALL of your original data intact for the highest quality.

Now, to qualify this a bit, the TIFF mode is surely a very capable mode, since only a very small amount of the image data is gone. So you could use TIFF mode to make or remake a great image, and have an image format that is compatible with any image processor out there, or any computer program that is modern. And, a JPEG image is very capable also. When modified only once, is beautiful to behold. JPEG images can only be diddled with to a degree, or your image will degrade. It is a widely compatible image format, since most digital "consumer" cameras default to it and pro cameras have the mode available.

Another consideration in digital imaging is short-term storage on the image card in your camera, or longer-term storage on your computer. The JPEG mode will definitely allow you to store more images. For instance, on my Nikon® D100, with a one-gigabyte IBM® Microdrive, I can store about 330 images in JPEG FINE mode, in RAW mode that drops to 107 images, and in TIFF mode, surprisingly, it drops to only 54 images. Due to how TIFF images store color information, they are nearly twice the size to store than RAW images. And the RAW mode contains more data for later use!

As this article is being written, and is mentioned briefly above, no RAW mode standard yet exists, although one has been proposed. Each camera manufacturer has proprietary RAW formats. If Adobe's new DNG (Digital Negative) standard RAW format is accepted by camera manufacturers, this may change. In the meantime, the software that pulls the image off of the camera is proprietary and will not work with another camera maker's images in RAW format. So this might be a drawback if you need maximum compatibility with the rest of the printing industry. But, with the new Photoshop CS this problem is going away. Most image shops will be using Photoshop, since it is the industry standard graphics program.

So, if you want maximum compatibility and maximum reusable quality, use TIFF mode. If you need maximum storage, and excellent initial image quality, use JPEG mode. If you want maximum quality period, use RAW mode.

Many do as I do, and shoot in RAW mode, store the image in RAW mode, and later make TIFF or JPEG images from the RAW images. I can do that over and over without losing my image quality. In fact, JPEG or TIFF images that have been converted on your computer from a RAW image are noticeably higher quality.

Why not go out and make a bunch of digital images today. Whatever mode you use will give you an excellent image later. You can experiment with the various formats and see which YOU like best. Digital photography makes this easy. Now that you have made the investment in digital camera equipment, you can shoot and shoot until you are satisfied, at no extra cost!

Most cameras will allow you to change formats at any time, and will store all the formats on the same camera image card, so, go and experiment a bit.


http://www.cleanimages.com/Article-AreYourImagesRaw.asp