Mastering
Digital SLR Photography

Format Proliferation

It’s no secret why there are so many “standard” image file formats. Vendors always think they can do something better than their competitors, or, at the very least, hope that you’ll think so. As a result, they invent a new file format with a few extra features that tweak the capabilities a tad. There’s the possibility that you’ll be locked into a particular set of tools because you want those extra features.

In some respects, it’s a wacky approach. Digital images consist primarily of rows and columns of pixels arranged in a bitmap. Each pixel might store 8 bits, 15 bits, 16 bits, 24 bits, 32 bits, or 48 bits of information. Some of those bits might be set aside to represent selections within an image. You also need the ability to store overlay-like layers, data about fonts used, and other information. Once you begin working on an image in an image editor, not a lot more data is required. You’d think that a single format would do the job. Yet, we’ve had many variations on TIFF, more than a few Photoshop PSD varieties, plus, in the olden days, proprietary formats like .IFF (Amiga), .TGA (Targa), .PXR (Pixar), .PX1 (PixelPaint), .PIC (SoftImage), or .RLA (Wavefront.)

The latest version of PSD is the closest thing we have to a standard file format, and that’s only for image editing. Your digital camera can’t read or produce PSD files at all. PSD can’t handle the kinds of information that digital cameras can record, such as a specific white balance, sharpness, variable tonal curves, and other data. When you take a picture, a host of this kind of picture information is captured in a raw form, and then immediately processed using settings you’ve specified in your camera’s menus. After processing, the image is stored on your memory card in a particular format, such as TIFF or JPEG. Once that’s done, any changes must be made to the processed data. If you decide you should have used a different white balance, you can no longer modify that directly, even though color balance changes in your image editor might provide a kind of fix.

So, digital camera vendors provide an alternative file format, generically called RAW, but in practice given other names, such as NEF (Nikon), CRW (Canon), or MRW (Minolta). The different names reflect the fact that each of these RAW formats is different and not compatible with each other. You’ll even find differences between RAW formats used by the same vendor. For example, while the RAW files produced by the Canon 20D and 1D Mark II both have a .CR2 extension, they each need their own RAW converter to import the files into a standard TIFF format. To date, there are more than 100 different “RAW” formats.

You’ll also find references to EXIF (Exchangeable Image File Format) specifications, which are part of the larger Design Rule for Camera File systems (DCF) that most vendors adhere to. Unfortunately, while EXIF and DCF provide standard methods for transferring information, camera vendors add on bells and whistles of their own in constructing the actual file formats that they use.

Of course, the reason for individual RAW formats is not to lock you into a particular camera system. The vendor has already done that by using a proprietary lens mount design. Ostensibly, the real reason is the one I outlined earlier: to do the job better than the other folks. Of course, in some cases, a particular RAW format is a thinly disguised TIFF file with a new file extension and some extra features, but in others RAW provides an unadulterated copy of the unprocessed data captured by the CCD or CMOS imager.

I don’t expect to see any massive reduction in the number of digital camera file formats in the future. It’s more likely that we’ll see even more formats down the road, but that in addition to the software provided by the camera maker, import filters for Photoshop will follow, and other third-party RAW file handlers, such as BreezeBrowser, Capture1, Irfanview and Bibble, will keep pace.

Image Size, File Size, and File Compression

Here’s a quick explanations:
■ Image size. This is the dimension, in pixels, of the image you capture. For example, if you have a 6MP camera, it may offer a choice of 3008 × 2000, 2560 × 1920, 1600 × 1200, 1280 × 960, and 640 × 480 resolutions. Each reduction in resolution reduces the size of the file stored on your memory card. A TIFF file at 2560 × 1920 pixels might occupy 4MB; a 1600 × 1200 pixel image, 1.7MB; a 1280 × 960 pixel image, 1.3MB, and a 640 × 480 pixel image less than 1MB.
■ File size. This is the actual space occupied on your memory card, hard disk, or other storage medium, measured in megabytes. The size of the file depends on both the image size (resolution) and quality/compression level. You can reduce the file size by reducing the image size or using a lower-quality/higher-compression setting.
■ Image quality. This is the apparent resolution of the image after it’s been compressed and then restored in your image editor. The TIFF format can compress the image, somewhat, with no loss of image quality, but JPEG compression does reduce the image quality, for reasons that will become clear shortly.
Keep the difference between image size, file size, and image quality in mind as we continue our discussion.

Image Compression Revealed
The next thing to clear up is the idea of compression. Compression comes in two varieties: lossless compression, like that provided with the RAW and TIFF formats, and lossy compression, like that afforded by the JPEG format. Understanding a little about how compression works makes these terms a little more understandable. Note that not all RAW and TIFF files are compressed. For example, Nikon’s original NEF format was uncompressed, producing 6 megapixel images that topped 11 megabytes in size, while its latest version is actually compressed, reducing the average size of these NEF files to about 5.7 megabytes. TIFF files can be stored uncompressed, too, either by the camera or by your editing software.

Bitmapped images, like all other computer code, are stored as a series of binary numbers, which are the only values a computer can handle. A string of 64 bits might look like this, but probably wouldn’t because I’ve simplified it for the sake of this illustration:

0000000000000011100000000000000001111110000000000000000000000001

You probably know (although not by choice) that computers can store eight bits in a single byte. So, the computer would need 8 full bytes to store that string of 64 binary numbers. If the image is a standard 24-bit full-color image, those 8 bytes might represent basic information about a mere two (and a fraction) pixels. Clearly, a megapixel image is going to occupy megabytes of storage space unless we can squeeze the information somehow.

That’s possible because any string of computer numbers contains redundant information. There are bits that aren’t needed to reproduce the original string precisely and with no loss of data. Suppose you were doing an inventory for your miniature golf course and lined up 64 of your golf balls as shown in the string above, with the 0s representing red golf balls and the 1s representing green golf balls. If you wanted to describe your lineup, would you say the row consisted of “red, red, red, red, red, red, red, red, red, red, red, red, red, red, red, green, green, green, red, red, red…?” Of course not. You’d say you “had 14 red balls, then 3 greens, 16 reds, 6 greens, 24 reds, 1 green…” as shown below.

When describing numbers rather than golf balls, the savings are even more dramatic. A lossless compression scheme, like that used to squeeze a TIFF file, could record a value that would designate how many times a particular set of bits (rather than golf balls) is repeated, so, instead of storing all 64 bits, a code would be used that meant “14 zeroes, followed by 3 ones, followed by 16 zeros, followed by 6 ones…” and so forth. That information would allow reconstructing the string of bits used in the example. Techie types call this kind of abbreviation “run length limited” because it records the lengths of the runs of the same number consecutively.

It gets better. As the compression algorithm worked, it would notice that certain strings of numbers began to repeat. Instead of enumerating only the number of runs of ones and zeros, the code would indicate where to find a string of numbers identical to the one that needed to be recorded next. The second time the line of numbers above turned up, a short code representing where that line is stored in the file would be substituted. In effect, the encoder/decoder would say, “go to location x,y in the table I’ve put together, and use the number you find there”. Obviously, the coordinates in a table can be expressed using a very small number, which allows squeezing the size of the file more and more as the size of the cross-referenced strings of numbers grows.

To represent a string such as 111101011110001111111111110001001000100100010010001000, you’d need only to list the addresses in the table of those numbers.

The larger the file becomes, the fewer actual numbers the compression scheme has to record. More and more of the code consists of pointers to strings of numbers. This method, called Huffman encoding, builds a frequency table of the number strings in a file, and assigns the shortest codes to the strings of numbers that occur most often.

Even though all the redundant numbers are eliminated from the file, the decompression algorithm can use the information to reconstruct the original file precisely. Today, more-advanced algorithms, such as the Lempel-Ziv Welch (LZW) algorithm used to compress TIFF files, are very efficient.

LZW was originally developed by Israeli researchers Abraham Lempel and Jacob Ziv in 1977 and 1978. The Lempel-Ziv algorithm was further developed by a Unisys researcher named Terry Welch, who in 1984 published and patented a compression technique that is now called Lempel-Ziv Welch (most often with no second hyphen, although even Unisys isn’t consistent in its use) or, simply, LZW.

Moreover
While the compression scheme used with TIFF files works well, TIFF files can still be massive. As transfer of images files over telecommunications lines became popular (this was even before the public Internet), a consortium called the Joint Photographic Experts Group (JPEG) developed a compression scheme particularly for continuous tone images that is efficient, and still retains the most valuable image information. JPEG uses three different algorithms: one called discrete cosine transformation (DCT), a quantization routine, and a numeric compression method like Huffman encoding.

JPEG first divides an image into larger cells, say 8 × 8 pixels, and divides the image into a special color space that separates the luminance values (brightness) from the chrominance (color) values. In that mode, the JPEG algorithm can provide separate compression of each type of data. Because luminance is more important to our eyes, more compression can be applied to the color values. The human eye finds it easier to detect small changes in brightness than equally small changes in color.

Next, the algorithm performs a discrete cosine transformation on the information. This mathematical mumbo-jumbo simply analyzes the pixels in the 64-pixel cell and looks for similarities. Redundant pixels—those that have the same value as those around them—are discarded.

Next, quantization occurs, which causes some of the pixels that are nearly white to be represented as all white. Then the grayscale and color information is compressed by recording the differences in tone from one pixel to the next, and the resulting string of numbers is encoded using a combination of math routines. In that way, an 8 × 8 block with 24 bits of information per pixel (192 bytes) can often be squeezed down to 10 to 13 or fewer bytes. JPEG allows specifying various compression ratios, in which case larger amounts of information are discarded to produce higher compression ratios.

Finally, the codes that remain are subjected to a numeric compression process, which can be similar to the Huffman encoding described earlier. This final step is lossless, as all the information that is going to be discarded from the image has already been shed.

Because it discards data, the JPEG algorithm is referred to as “lossy.” This means that once an image has been compressed and then decompressed, it will not be identical to the original image. In many cases, the difference between the original and compressed version of the image is difficult to see.

Compressed JPEG images are squeezed down by a factor of between 5:1 and 15:1. The kinds of details in an image affect the compression ratio. Large featureless areas such as areas of sky, blank walls, and so forth compress much better than images with a lot of detail. Figure below shows an image (a close-up of a goose’s eye) at two high compression settings (top) and two low compression settings (bottom).

This kind of compression is particularly useful for files that will be viewed on Web pages and sent as e-mail files. It’s also used to squeeze down digital camera files. However, more quality is lost every time the JPG file is compressed and saved again, so you won’t want to keep editing your digital camera’s JPEG files. Instead, save the original file as a TIFF file, and edit that, reserving the original as just that, an original version you can return to when necessary. In fact, it’s a good idea to save this digital negative on a CD or DVD so you can go back to your original file at any time in the future, no matter how much you’ve butchered (or improved) the image since.

About Those Formats

This section will list each of the important file formats available for use both with digital cameras and image editors, including a few that you should avoid when working with images. I’ll discuss their advantages, disadvantages, and the types of image compression used. First, we’ll look at the file formats that are not used with digital cameras.

Formats Used for Image Editors/Display/Printing Only
Of course, digital cameras are far from the only application for digital image files. You’ll commonly work with these files to display them on Web pages (generally JPEG and GIF formats), to show text and graphics in a standardized way for viewing, printing or reproduction (PDF format), or for image editing.

GIF
GIF, or Graphics Interchange Format, was developed as one of the original “squeezed” file formats suitable for distribution online, back in 1987, even before the public Internet. The goal in developing this format was to create a way to share compressed graphics between different computer platforms. That’s a bigger deal than you might think. In those days it was tricky to create image files on one computer that could be readily viewed on another computer, and with 300 to 1200 baud modems, even small image files could take many minutes to upload or download. The online service CompuServe was the first big user of the GIF format.
The GIF format converts images into files with a maximum of 256 colors. Few video cards in those days could display more than 256 colors, anyway, so that sufficed. GIF achieves its small file size by first reducing the colors available in an image to 1 to 256 different hues, then squeezing the file further by applying LZW compression to the indexed color tables that remain. So, GIF can be considered both a lossy and lossless file format. It loses picture information when the number of colors are reduced (but if the number of colors in an image is already 256 hues or fewer, no colors are discarded), but the remaining information is preserved 100 percent.
GIF has some other features that are useful chiefly for Web display, such as interlacing (which allows an image to be displayed progressively as it downloads), transparency (which makes it possible for a GIF image to show the page background in its transparent parts), and animation (several images embedded in one file and shown consecutively, like an animated cartoon).
Because it can handle no more than 256 colors, GIF is a poor choice for digital camera images (which look posterized when converted to 256 tones), and is best used for logos, dialog boxes, line art, charts, and other graphics that don’t involve continuous tones. Its compression scheme works great with images that have few colors, producing files that can be even smaller than those afforded by JPEG.

JPEG 2000
JPEG 2000 is a relatively new file format, supported by Photoshop CS and some other image editors, but not universally by the applications that we’d find the most useful: Web browsers.
At this time, no digital cameras produce files in this format. JPEG 2000 uses a compression scheme called wavelet compression (for roughly 20 percent smaller files), which provides better image quality, but still discards some information. JPEG 2000 files may have extensions like .jpx, jpc, or .jp2.
JPEG 2000 offers the ability of downloading a lower-resolution image first, so you can preview the image in your Web browser and decide whether to continue to download the page.
While conventional JPEG works only with RGB images, this new version is compatible with RGB, L*a*b color, and CMYK (cyan, magenta, yellow, black) color models. It can also include color profile information, as well as informational tags such as the owner of the image. JPEG 2000 also offers a lossless compression mode, which reduces the file size by roughly 50 percent, while not discarding any information.
JPEG 2000 has a very cool feature called Region of Interest, which you can use to designate the most important parts of an image. When you’ve done that, image compression will be concentrated in other areas of the photo, preserving more detail in your Region of Interest. Keep in mind that anyone trying to read your JPEG 2000 image must have a compatible application or plug-in.

PDF
PDF (Portable Document Format) is a format originally developed by Adobe to store PostScript files for printing on PostScript printers. Its advantage is that it preserves the original layout, fonts, and appearance of the file. PDF is often used with Adobe Reader or with browser plugins to display documents. I download instruction manuals, IRS tax forms, and other documents in PDF format. You don’t need a PostScript printer to print out PDF files, either.
More recently, PDF has gained some favor in the pre-press environment as a way of prepping documents for printing, and in the Macintosh world as a replacement for the PICT format.
Because PDF files consist of PostScript text instructions, they can be compressed highly using any lossless compression method.

PICT
PICT is a file format that was developed in 1984 by Apple Computer as the native format for Macintosh graphics. PICT can include both bitmap images and vector (line-oriented) graphics.
Although PICT is used primarily to exchange graphics between Mac applications, many PC programs, such as the Windows version of Photoshop, support it. Apple has elected to replace PICT with PDF, beginning with Mac OS X.
PICT supports grayscale images as well as up to 24-bit color images (it also can use 32-bit images, but the extra 8 bits are used for selections as an alpha channel). PICT uses a Huffmanlike run-length encoding (RLE) compression scheme.

BMP
BMP was developed by Microsoft as a standard bitmap file format for computers running the Windows operating system. The intent was to produce device-independent bitmaps (DIB) that Windows can display on any type of device. BMP files can include color depths up to 24 bits.

PNG
The PNG (Portable Network Graphics) format was designed as a replacement for GIF, because the compression algorithm used in GIF was patented by Unisys, and developers supporting the GIF format were theoretically required to pay Unisys a royalty. The patent expired in June, 2003 in the United States, and in Canada, Japan, and Europe in 2004, so royalties will be charged only in countries in which the patent has not fizzled out (in other words, virtually nowhere).
That leaves PNG, a format that never saw much favor, even further in limbo than it was before. Even though PNG has some advantages over GIF or even JPEG, it’s unlikely to flourish in the future. PNG uses optimized preprocessing filters that improve lossless compression efficiency, particularly in 24-bit images. Unlike GIF, PNG can specify any combination of 256 colors for transparency, embed gamma values so the image displays well on both Macs and PCs (which use different gamma settings), and beats both GIF and TIF for compressing images.

PCX
PCX is an early graphics file format established by Zsoft for its PC Paintbrush software. It supports 24-bit color, and provides decent lossless file compression, but is now used only as a backup format. I sometimes save files in PCX format when the recipient is having trouble reading my TIFF files. Unlike TIFF, PCX doesn’t have a wide variety of options and is thus more “standardized” and compatible with a wider variety of software on Mac, PC, and Linux platforms. No digital cameras use PCX, but most image-editing software supports it.

Formats Used in Digital Cameras
There are three formats used in digital cameras: JPEG, TIFF, and the various types of RAW. There are advantages to each, as well as a few pitfalls to avoid.

JPEG
JPEG is the most common format used by digital cameras to store their images, as it was designed specifically to reduce the file sizes of photographic-type images. It provides a good compromise between image quality and file size, and produces images that are suitable for everyday applications. Those who work with point-and-shoot digital cameras may use nothing else but JPEG, and even many dSLR owners find that the default JPEG settings offer quality that’s good enough for ordinary use. Indeed, on a sharpness basis, it can be difficult to tell the difference between the best-quality JPEG images and those stored in RAW or TIFF formats. But, as you’ll see, there are additional considerations that come into play.
As you probably know, JPEG allows dialing in a continuous range of quality/compression factors. In image editors, you’ll find this range shown as a quality spectrum from, say 0 to 10 or 0 to 15. Sometimes, very simple image editors let you choose only from Low, Medium, or High quality. Those are just different ways of telling the algorithm how much information to discard.
Many digital cameras, on the other hand, lock you into a limited number of quality settings with names like Standard, Fine, Extra Fine, or Super Fine, and don’t tell you exactly which JPEG quality settings those correspond to. The names for the quality settings aren’t standardized, and a particular setting for one camera doesn’t necessarily correspond to the same quality level with another camera. For example, Super Fine may be the highest lossy JPEG setting with one model, and the lossless TIFF setting with another vendor’s camera.
You’ll usually find no more than three JPEG compression choices with any particular digital SLR. Some Nikon cameras, for example, offer Fine, Normal, and Basic. If you’re concerned about image quality, and want to use JPEG, you should probably use the best JPEG setting all the time, or alternate between that and the TIFF or RAW settings. Your choice might hinge on how much storage space you have. When I’m photographing around the home where I have easy access to a computer, I use RAW. When I travel away from home, I switch to JPEG if I think I’m going to be taking enough pictures to exceed the capacity of the 2 to 3 gigabytes of memory cards I carry around with me at all times.
That might be the case when shooting many sports sequence shots. It’s easy to squeeze off a burst of 6 to 8 shots on any given play, and a dozen plays later notice you’ve used up 512MB or more of RAW photos in a relatively short period of time. Although memory cards are relatively inexpensive, even if you carry 4GB or more of digital film, you’ll find that Parkinson’s law applies to digital photography: Photos taken expand to fill up the storage space available for them. Some cameras are able to store photos to the memory card more quickly in JPEG format rather than TIFF or RAW, so that is another consideration for sequence shots. If quality isn’t critical, then use lower-quality JPEG settings with your camera to fit more images on the available storage.

TIFF
Pure TIFF, one of the original lossless image file formats, is on its way out in the digital camera world. In the past, many of the higher-end point-and-shoot cameras offered JPEG, with TIFF as a higher-quality option. I can’t recall the last time I used a brand-new non-dSLR camera that used TIFF, and I test 8 to 10 of these every month. TIFF is even dying out among dSLR cameras. Many of the latest models offer only JPEG and RAW, or, perhaps, a JPEG+RAW mode that stores the same image in both formats. A few still offer TIFF, but their numbers are small.
The original rationale for using TIFF at all was that it provided a higher-quality option in a standard format, without the need for the vendor to develop a proprietary RAW format. Today, the additional advantages of RAW when it comes to tweaking images make RAW well worth the trouble.
TIFF, or Tagged-Image file Format, was designed in 1987 by Aldus (later acquired by Adobe along with Aldus’ flagship product, PageMaker) to be a standard format for exchange of image files. It’s become that, and was at one time supported by virtually all high-end digital cameras as a lossless file option, even though its use has diminished today. However, because TIFF supports many different configurations, you may find that one application can’t read a TIFF file created by another. The name itself comes from the tags or descriptors that can be included in the header of the file, listing the kinds of data in the image. TIFF can store files in black/white, grayscale, 24-bit, or 48-bit color modes, and a variety of color models, including RGB, L*a*b, and CMYK. If you’ve used Photoshop, you know that TIFF can store your levels and selections (alpha channels) just like Photoshop’s native PSD format. It uses a variety of compression schemes, including no compression at all, Huffman encoding, LZW, and something called Pack Bits. Most applications can read TIFF files stored in any of these compression formats.

RAW
As applied to digital cameras, RAW is not a standardized file format. RAW is a proprietary format unique to each camera vendor, and, as such, requires special software written for each particular camera. Each RAW format stores the original information captured by the camera, so you can process it externally to arrive at an optimized image. You’ll learn more about RAW in the next section.

Use JPEG, TIFF, or RAW?

Of the three file formats, which should you use? JPEG files are the most efficient in terms of use of space, and can be stored in various quality levels, which depend on the amount of compression you elect to use. You can opt for tiny files that sacrifice detail or larger files that preserve most of the information in your original image.

Some cameras also can save in TIFF format, which, although compressed, discards none of the information in the final image file. However, both JPEG and TIFF files have been processed by the camera before they are created. The settings you have made in your camera, in terms of white balance, color, sharpening, and so forth, are all applied to the image. You can make some adjustments to the image later in an image editor like Photoshop, but you are always working with an image that has already been processed, sometimes heavily.

The information captured at the moment of exposure can also be stored in a proprietary, native format designed by your camera’s manufacturer. These formats differ from camera to camera, but are called Camera RAW, or just RAW for convenience. You might think of RAW as a generic designation rather than a specific format, just as the trade name Heinz applies to all 57 varieties instead of just one.

A RAW file can also be likened to a digital camera’s negative. It contains all the information, stored in 12-bit, 14-bit, or 16-bit channels (depending on your camera), with no compression, no sharpening, no application of any special filters or processing. In essence, a RAW file gives you access to the same information the camera works with in producing a 24-bit JPEG or TIFF file. You can load the RAW file into a viewer or image editor, and then apply essentially the same changes there that you might have specified in your camera’s picture-taking options.

Figures below provide an illustration. Right figure shows a scenic shot as stored in JPEG format by the digital SLR. It’s a difficult image to expose properly, with inky shadows and very bright highlights in the sky. The processed image is much too dark and too contrasty. Center figure shows what happens when you try to salvage such a picture by manipulating curves in Photoshop. The shadows are easy enough to brighten, but there was no detail in the sky area in the JPEG version, so there’s not much that could be done.

Because my camera stored both JPEG and RAW versions of the same image, I was able to manipulate the RAW image to arrive at the results in the left figure. Not only could I improve the contrast, but I tweaked the white balance and boosted the saturation at the same time. Clearly, working with the RAW image was the way to go.

Some RAW formats, such as those deployed by Nikon and Canon for their high-end cameras, are actually TIFF files with some proprietary extensions. That doesn’t mean that an application that can read standard TIFF files can interpret them, unfortunately. Usually, special software is required to manipulate RAW files. If you’re lucky, your camera vendor supplies a special RAW processing application that is easy to use and powerful. For example, Nikon offers Nikon View to read and manipulate its .NEF files. Canon provides a viewer for its .CRW format. Minolta includes a DiMAGE Viewer for its RAW files.

If you’re not so lucky, you’ll get a less capable utility, be asked to pay extra for it, or find that none at all is available. Photoshop CS now includes a Camera RAW plug-in (which was formerly an extra-cost option with Photoshop 7) that works quite well. It can be used only with the particular digital cameras that Adobe has elected to support. The list is long, and includes many popular cameras from Nikon, Canon, and Minolta. You’ll find that third parties also provide RAW decoders for specific camera models, such as YarcPlus and BreezeBrowser for Canon, and Bibble Pro for Nikon, Canon, Olympus, Pentax, Minolta, Fuji, Kodak, and other dSLRs. The great Windows freeware utility IrfanView can handle many RAW files such as Canon’s .CRW format.

As I noted earlier, I sometimes shoot JPEG images when I think it is likely I may exceed my memory card capacity, or when I’m taking test photos that don’t really matter. For most dSLR shooters, using JPEG format exclusively may be false economy. You never know when that “unimportant” snapshot might develop into an important photo that you wish you could manipulate in RAW form. JPEG may be “good enough,” but if you’re using a digital SLR, you probably aren’t willing to settle for “good enough” most of the time.

For that reason, many digital photographers, myself included, shoot nothing but RAW images or, sometimes, RAW+BASIC (with a second copy of the image in JPEG format). Here’s the rationale as it relates to workflow:
■ Some newer cameras take no longer to store RAW files on digital media when in burst mode, so you can shoot sports and other action in RAW without slowing down the camera.
Some are even able to store a pair of RAW/JPEG files quickly enough to maintain burst mode. It all depends on the size of the digital SLR’s buffer, and how well the camera can multitask: shooting pictures while storing the previous shot on the memory card.
■ Because they are several times larger, RAW files will take longer to transfer from your camera or memory card to your computer. If you’re in a big hurry, the extra wait can be frustrating. So, you’ll want to use the fastest transfer method available, such as a card reader that is USB 2.0 compatible.
■ When you shoot RAW exclusively, you may end up with files that cannot be collected by your favorite image management/cataloging/albuming program. My own preference is for an older application that doesn’t read RAW files, so when I transfer my RAW files I have no way of reviewing them quickly.
We have two solutions. If in a particular hurry, just shoot RAW+BASIC so we are able to catalog the JPEG versions quickly for immediate review. If we are in less of a hurry, just use a conversion program to duplicate each RAW image in TIFF format, in batch mode. The TIFFs can be catalogued and reviewed, and are sometimes good enough to work with directly in Photoshop. If not, always have our RAW original.
■ As one of the last steps in your workflow, you should archive a copy of the original RAW files to CD-R or, more common today (because a CD-R may hold only 100 RAW images), to DVD. That will preserve your original negative so you can return to it any time in the future.

RAW Applications

Your software choices for manipulating RAW files are broader than you might think. Camera vendors always supply a utility to read their cameras’ own RAW files, but sometimes, particularly with those point-and-shoot cameras that can produce RAW files, the options are fairly limited. Most Canon dSLR users have gone beyond the Canon File View Utility to something better from third parties, such as Capture1. Other vendors, such as Nikon (with its Nikon Capture) offer RAW file handling that is much more flexible and powerful.

Because of the spotty capabilities among proprietary RAW converters offered by digital camera vendors, there is a flourishing market for third-party solutions. These are usually available as standalone applications (often for both Windows and Macintosh platforms), as Photoshopcompatible plug-ins, or both. Because the RAW plug-ins displace Photoshop’s own RAW converter, I tend to prefer to use most RAW utilities in standalone mode. That way, if I choose to open a file directly in Photoshop it automatically opens using Photoshop’s fast and easy-to-use Camera RAW plug-in. If I have more time or need the capabilities of another converter, I can load that, open the file, and make my corrections there. Most are able to transfer the processed file directly to Photoshop even if you aren’t using plug-in mode. This section provides a quick overview of the range of RAW file handlers, so you can get a better idea of the kinds of information available with particular applications. I’m going to include both high-end and low-end RAW browsers so you can see just what is available.

Converters Offered by Camera Vendors
As I mentioned, the file converters offered by camera vendors is a mixed bag. Some are great, some are acceptable, and some are abominable. The best part is that they are generally bundled with the camera and offered at no cost. Nikon offers a basic RAW converter with its cameras, but if you want the real thing, you’ll have to pay $99 for Nikon Capture. Here are some of the utilities available from camera vendors.

Kodak Professional DCS Photo Desk
This is the viewer used with Kodak’s 14MP DCS Pro 14n and its variations. (n is the Nikon model; Kodakalso offers a similar camera based on the Canon system.) As you might guess, the amount of information at your fingertips is astounding. For example, look at the sorts of data you can discover in the Image Info window, shown in figure below. It includes things like the camera serial number (useful if you’re working with several digital cameras and want to know which was used to produce the image), resolution, file size, ISO setting, type of metering used, flash sync mode, the focal length of the lens, and the exact time and date the photo was taken. If you annotated the image with a sound bite at the time you took the picture, you can play that back through your computer’s speakers.

Professionals will love the Job Tracker dialog box, which lets you enter more information, including caption and credits, in an approved International Press and Telecommunications (IPTC) format. Anyone shooting digital pictures for publication will find this capability useful.Other controls, allow you to compensate for exposure, change the white balance and lighting, add noise reduction, or improve sharpness, exactly as you could with the camera.

Nikon Capture
First introduced in 1999, Nikon Capture is an extra-cost RAW converter/editor application that works with JPEG, TIFF, or NEF (Nikon’s RAW format) files. You can make modifications to a RAW format file, and then resave it as a RAW file with adjustments, while retaining the original information in case you want to revert to an earlier state or make additional changes later on.

One handy feature is the ability to “defish” images taken with fisheye lenses, producing a non-distorted rectilinear image that no longer has the fisheye qualities. Supported lenses include the DX Nikkor 10.5mm fisheye, which produces an image equivalent to a 16mm lens on a 35mm film camera. When such images are defished, they produce super-wide rectangular photos with some loss of sharpness in the corners, but which are still quite usable. Nikon Capture gives you direct control over curves, levels, brightness/contrast, color balance, unsharp masking, optional color noise reduction, and exposure compensation.

Most settings are accessed by expanding the Tool Palette to produce controls. These include the LCH Editor, which lets you make adjustments to lightness, chroma, and hue separately. There’s also an Image Dust Off feature: Take a dust reference image with your camera, and Nikon Capture will remove dust spots from a batch of images.

Batch processing lets you convert a whole folder of images using the same settings. A folder can be set on “watch” status, and Nikon Capture will process any new images dropped into the folder as they arrive. Those who want to control their camera remotely can use the application’s Remote Capture feature to take pictures on cue or on a regular schedule in timelapse mode.

Canon EOS File Viewer Utility/EOS Capture/Digital Photo Professional
Canon provides these software utilities for viewing/converting images taken with Canon cameras, and for controlling the camera remotely. The File Viewer Utility is not highly regarded by Canon users, who often opt for a third-party solution. Or, Digital Photo Professional is preferred for those Canon dSLR cameras that are supported by it.

DPP, shown in figure below offers much higher-speed processing of RAW images than was available with the sluggardly File Viewer Utility (as much as six times faster). Canon says this utility rivals third-party standalone and plug-in RAW converters in speed and features. It supports both Canon’s original .CRW format and the newer CR2 RAW format, along with TIFF, Exif TIFF, and JPEG.

You can save settings that include multiple adjustments and apply them to other images, and use the clever comparison mode to compare your original and edited versions of an image either side by side or within a single split image. The utility allows easy adjustment of color channels, tone curves, exposure compensation, white balance, dynamic range, brightness, contrast, color saturation, ICC Profile embedding, and assignment of monitor profiles. A new feature is the ability to continue editing images while batches of previously adjusted RAW files are rendered and saved in the background.

Other Proprietary RAW Converters
There isn’t room in this chapter to provide even these brief overviews of the similar software available from the manufacturers of the other dSLRs. You’ll find that Olympus, Pentax, Minolta, and other vendors of digital SLRs provide similar programs with the same types of features. If your particular camera’s RAW converter doesn’t do everything you like, you’ll want to explore one of the third-party solutions discussed next.

Note that most of the products with a price tag can be downloaded for 30-day free trials, including the likes of Bibble and Capture One. The URLs for these downloads change frequently (Phase One, for example, is based in Denmark, but makes its products available for download through other distributors), so if you’d like to try one of these out, do a search engine search for the latest link.

Third-Party Solutions
You’ll find that RAW file utilities are available from a wide range of suppliers and can cost you nothing (in the case of IrfanView) or be included in the cost of other software (which is the case with Photoshop). Or, you can pay $129 for a sophisticated program like Bibble Professional, or as much as $500 for a top-of-the-line program like PhaseOne’s Capture One Pro (C1 Pro).

IrfanView
At the low (free) end of the scale is IrfanView, a Windows freeware program you can download at www.irfanview.com. It can read many common RAW photo formats, like the Minolta format. It’s a quick way to view RAW files (just drag and drop to the IrfanView window) and make fast changes to the unprocessed file. You can crop, rotate, or correct your image, and do some cool things like swapping the colors around (red for blue, blue for green, and so forth) to create false color pictures. The price is right, and IrfanView has some valuable capabilities.

Phase One Capture One Pro (C1 Pro)
If there is a Cadillac of RAW converters for Nikon and Canon digital SLR cameras, C1 Pro has to be it. This premium-priced program does everything, does it well, and does it quickly. If you can’t justify the price tag of this professional-level software, there are “lite” versions for consumer, serious amateur, and cash-challenged professionals called Capture One dSLR, and Capture One dSLR SE.

Aimed at photographers with high-volume needs (that would include school and portrait photographers, as well as busy commercial photographers), C1 Pro is available for both Windows and Mac OS X, and supports a broad range of Nikon and Canon digital cameras. Phase One is a leading supplier of megabucks digital camera backs for medium and larger format cameras, so they really understand the needs of photographers.

The latest features include individual noise reduction controls for each image, automatic levels adjustment, a “quick develop” option that allows speedy conversion from RAW to TIFF or JPEG formats, dual-image side-by-side views for comparison purposes, and helpful grids and guides that can be superimposed over an image. Photographers concerned about copyright protection will appreciate the ability to add watermarks to the output images.

Bibble Pro
One of my personal favorites among third-party RAW converters is Bibble Pro, which just came out with a new version as I was writing this book. It supports one of the broadest ranges of RAW file formats available, including NEF files from Nikon D1,D1x/h, D2H, D100; .CRW files from the Canon C30/D60/10D/300D; .CR2 files from the Canon 1D MKII; .ORF files from the Olympus E10/E20/E1/C5050/C5060; .DCR files from the Kodak 720x/760/14n; .RAF files from the Fuji S2Pro; .PEF files from Pentax ISTD; .MRW files from the Minolta Maxxum; and .TIF from Canon 1D/1DS.
The utility supports lots of different platforms, too. It’s available for Windows, Mac OS X, and, believe it or not, Linux.

Bibble works fast because it offers instantaneous previews and real-time feedback as changes are made. That’s important when you have to convert many images in a short time (event photographers will know what I am talking about!) Bibble’s batch-processing capabilities also let you convert large numbers of files using settings you specify without further intervention.

Its customizable interface lets you organize and edit images quickly, and then output them in a variety of formats, including 16-bit TIFF and PNG. You can even create a Web gallery from within Bibble. I often find myself disliking the generic filenames applied to digital images by cameras, so I really like Bibble’s ability to rename batches of files using new names that you specify.

Bibble is fully color managed, which means it can support all the popular color spaces (Adobe sRGB, and so forth) and use custom profiles generated by third-party color-management software.
There are two editions of Bibble, a Pro version and a Lite version. Because the Pro version is reasonably priced at $129, I don’t really see the need to save $60 with the Lite edition, which lacks the top-line’s options for tethered shooting, embedding IPTC-compatible captions in images, and cannot also be used as a Photoshop plug-in (if you prefer not to work with the application in its standalone mode).

BreezeBrowser
BreezeBrowser, has long been the RAW converter of choice for Canon dSLR owners who run Windows and who were dissatisfied with Canon’s lame File Viewer Utility. It works quickly, and has lots of options for converting CRW files to other formats.
You can choose to show highlights that will be blown out in your finished photo as flashing areas (so they can be more easily identified and corrected), use histograms to correct tones, add color profiles, auto rotate images, and adjust all those raw image parameters, such as white balance, color space, saturation, contrast, sharpening, color tone, EV compensation, and other settings.

You can also control noise reduction (choosing from low, normal, or high reduction), evaluate your changes in the live preview, and then save the file as a compressed JPEG, or as either an 8-bit or 16-bit TIFF file. BreezeBrowser can also create HTML Web galleries directly from your selection of images.

Photoshop CS
The latest version of Photoshop includes a built-in RAW plug-in that is compatible with the proprietary formats of a growing number of digital cameras, both new and old. This plug-in also works with Photoshop Elements 3.0. The list of supported cameras at the time this book was published is a long one, shown in table below.

To open a RAW image in Photoshop CS, just follow these steps (Elements 3.0 users can use much the same workflow):
1. Transfer the RAW images from your camera to your hard drive.
2. Choose Open from the File menu, or use Photoshop’s File Browser.
3. Select a RAW image file. The Camera RAW plug-in will pop up, showing a preview of the image, like the one shown in the figure below.
4. Rotate the preview image using the Rotate Preview buttons.
5. Zoom in and out using the Zoom tool.
6. Adjust the RGB levels using the Histogram and RGB Levels facilities.
7. Make other adjustments (described in more detail below).
8. Click OK to load the image into Photoshop using the settings you’ve made.

Photoshop’s Camera RAW plug-in lets you manipulate many of the settings you can control within your camera. Here are some of the most common attributes you can change. This is an overview only. Check your Photoshop HELP files for more detailed information on using these controls.
■ Color Space.
It’s possible your digital camera lets you choose from among several different color space profiles, such as Adobe RGB or sRGB. The RAW file will be saved by the camera using the camera’s native color space. You can change to another color space using the Space drop-down list shown at lower left in Figure 5.19.
■ Depth.
Here you’ll choose 8 bits or 16 bits per color channel. Photoshop CS now supports more functions using 16-bit channels, so you might want to preserve the full depth of information available.
■ Pixel Size.
Usually, you’ll choose to open the image at the same resolution it was recorded at. If you plan to resample to a larger or smaller size, you might find that carrying out this step on the RAW file yields better results because of the new algorithm incorporated in this version of the plug-in.
■ Resolution.
This is the resolution that will be used to print the image. You can change the printing resolution to 300 or 600 pixels per inch (or some other value) to match your printer.
■ White balance.
You can change this to a value such as Daylight, Cloudy, Shade, Tungsten, Fluorescent, or Flash, or leave it at As Shot, which would be whatever white balance was set by your camera (either automatically or manually). If you like, you can set a custom white balance using the Temperature and Tint sliders.
■ Exposure.
This slider adjusts the overall brightness and darkness of the image. Watch the histogram display at the top of the column change as you make this adjustment, as well as those for the four sliders that follow.
■ Shadows.
This slider adjusts the shadows of your image. Adobe says this control is equivalent to using the black point slider in the Photoshop Levels command.
■ Brightness.
This slider adjusts the brightness and darkness of the image, similarly to the Exposure slider, except that the lightest and darkest areas are clipped off, based on your Exposure and Shadow settings, as you move the control.
■ Contrast.
This control manipulates the contrast of the midtones of your image. Adobe recommends using this control after setting the Exposure, Shadows, and Brightness.
■ Saturation.
Here you can manipulate the richness of the color, from zero saturation (gray, no color) at the –100 setting to double the usual saturation at the +100 setting.

Additional controls are available on the Detail, Lens, and Calibrate tabs, shown in three figures below.
■ Sharpness.
This slider applies a type of unsharp masking using a sophisticated algorithm that takes into account the camera you’re using, the ISO rating you used, and other factors. If you’re planning on editing the image in Photoshop, Adobe recommends not applying sharpening to the RAW image.
■ Luminance Smoothing/Color Noise Reduction.
Both these sliders reduce the noise that often results from using higher ISO ratings. Each control works with a different kind of noise. Luminance noise is the noise caused by differences in brightness, while color noise results from variations in chroma.
■ Lens Tab settings.
These are technical adjustments you can use to compensate for weaknesses in your lens’ design. Most of us don’t have the slightest idea what these are, and can safely ignore them.
■ Calibrate Tab settings.
These settings let you make calibrations in the way the Camera RAW plug-in adjusts hues, saturation, or shadow tints. If you consistently find your images end up too red, blue, or green, or have a color cast in the shadows, you can make an adjustment here.