Most Digital SLRs, regardless of the manufacturer, will allow you to shoot in two formats: RAW and best quality, high resolution JPEG. Despite the fact that RAW files use up significantly more camera storage space than JPGs, they are the preferred format choice among many professional photographers.

But what is a RAW file? According to one camera manufacturer “RAW images are extremely high-quality images that are not degraded by compression algorithms when recorded. However, they are not supported by most image editing programs in their native format, so they must be converted before use” (Canon Inc. Software Starter Guide, p. 33).

What is a JPEG? “The JPEG standard was written by the committee known as the Joint Photographic Experts Group, and it was designed for compressing full color or grayscale images (in particular, photographs and similar high-quality artwork). JPEG is a 'lossy' file format; when the JPEG algorithm compresses the image, it reduces the size by chucking bits of the image away. How does it know what to lose? JPEG compression plays on the fact that the human eye can only see so much. We have trouble seeing small color changes, so JPEG loses some of this subtle information" (Una Dooney).

So, which format should you use, RAW or JPEG?

Logically, and for maximum control over the final image, the choice seems obvious—RAW is best. It can be usefully edited in RAW coversion software—contrast, exposure compenstaion, fill light, colour temperature, curve/levels, sharpness and noise—and saved out as a high quality 48-bit (16-bits per colour channel) TIFF file for further detailed work. Software such as Adobe's complex Lightroom takes RAW editing and conversion to an impressive new level and is helping to make the RAW format more popular than ever.

But even with all this support, surely there are other issues for keen amateurs to consider. In fact, shooting RAW images all the time, or even at all, might not be best approach for you. It could be that the additional workload wouldn't suit you. You may ultimately feel that for all the hype the extended flexibility of RAW processing doesn't show its hand clearly enough in your prints.

In time you may conclude that the more typical ideology that exists among accomplished professionals is rarely tempered by common sense. The needs of the average amateur, shooting on a budget while holding down a demanding job perhaps, isn’t particularly well catered for in many photographic publications. Photo forums and pro/semi-pro websites can compound the problem by touting RAW as the obvious choice for "serious" photographers while glibly labelling the humble JPEG as the simple alternative for holiday snaps.

RAW files are often promoted as "digital negatives" because they are the originals you can always come back to and reprocess, but in a sense JPEGs are too. The deliberately underexposed shot on the left is the original JPEG straight from the DSLR and beside it is the JPEG version of the carefully processed TIFF. Layers, masks and the erasure and cloning tools were all used in its creation. The original can be revisited and processed again and again in a variety of ways. JEPGs converted to TIFFs are flexible enough to let you to deal with less severe exposure problems and typical colour casts (see below). A JPEG straight from a DSLR is a camera-processed RAW file, but that processing doesn't need to be excessive. To allow for more possibilities in image-editing software, camera JPEG processing should be kept to a minimum with very little sharpening, reduced contrast and neutral colour.

If you are a DSLR amateur, the most sensible approach is to shoot RAW and JPEG. Then, after careful processing, examine your prints to help you decide if the difference is actually worthwhile to you. You will also need to make decisions about which workflow (method of processing) best suits your lifestyle and photographic objectives. You may be very happy with your digital prints and JPEG slideshows from quality JPEG files.

When all is said and done even serious amateurs don't need be too bothered by those on forums and photographic websites who forever rabbit on about the foolishness of "throwing away" valuable image data. This line of reasoning is too simplistic and on the whole it's not as clear cut as some RAW fans suggest. There just isn't one rule for everybody!

Finally, do remember that whatever you shoot it’s always best to edit images in a format that doesn’t degrade slightly with use—TIFF, for example, or the native format of your preferred image-editing program.

The RAW vs JPEG Debate

The following quotes from professionals and amateur contributors strongly suggest that a photographer’s intelligent choice of shooting format is very much dependant on his or her personal goals and preferences.

“RAW conversion is… defined as the way to interpolate the missing other colors in the RGB image.

"For JPG and TIFF files this interpolation is done by the processor chip in the camera and also, to save processing time, it is done for 8 bits of the available 12 bits of pixel information. In this process the other 4 bits are discarded unused.

“Now we can explain why the RAW file can be compact and still keep all 12 bits of colour information. The RAW file is a dump of the grey scale data that the CCD captures, and it is then compressed by a mostly lossless compression scheme. This is what gives us a compact file and even more colour information than the JPG/TIFF files produced inside the camera” (Digital Outback Photo).

“JPEG has been widely criticized for the fact that every time you save a JPEG image some image data is lost due to compression. There is a cumulative effect since this occurs every time you save the image… It takes repeated saving of the data before any kind of degradation becomes obvious… As a general rule of thumb, low-res JPEGs will show degradation much more quickly than hi-res JPEGs” (Jim McGee, vividlight.com).

“I've had very good results shooting in the JPEG High image quality setting. I like the number of images I can put on my CF card and the results I'm getting making 13x19 prints from digital capture. However, I know that the RAW file (Nikon's NEF file) stores the maximum amount information or data within each photographic capture without losing anything to compression. Compare JPEG's 8 bit per channel or about 256 shades of gray per channel and 16.7 million colors, to the RAW file that allows you to capture the camera's 12 bits, 4,096 shades of gray per channel, the approximate 68.7 billion colors, and you can quickly see how the RAW file can be very useful in capturing the subtle details of an image just as you experienced it. This is also important information should you decide to make large high-quality prints” (Gary W Stanley, vividlight.com).

"RAW can be an essential format in certain situations but it simply isn't for everyone and its value has been overhyped"

Rob Sheppard*

“…you've probably been told that Raw files are 12-bits and JPEG files are 8-bits so they're 'better'. However that is apples vs. oranges. The 12-bit CCD is a linear encoding of light. Each of the 4096 levels represents an equal number of photons. The human visual system's response to light isn't linear though. Humans are sensitive to percentage changes in light, not absolute changes. So at the high end of the 4096 values there is "too much" information (the brightest stop of light is represented by 2048 separate values, from 2048 to 4095) while at the low end of the 4096 values there is 'too little' information (the darkest stop of light is represented by only 2 values, 1 and 2!).

“The camera uses a tone curve (essentially a modified gamma curve) to push that a little further, into an 8-bit (256-value) encoding. Sure there is some small loss of mathematical detail, but if the tone curve is the right one for the image and you don't need to move the exposure after the fact you'll be hard pressed to see the difference. And since essentially every output device in common use is 8-bits or less per color, your software is going to need to convert the image to 8-bits per color at some point in any case. The only advantage of doing it on the computer is that you can change your mind or re-purpose the image after the fact by doing it several different ways.

“A very similar argument is also heard about JPEG compression. There is a gnawing fear that somehow because JPEG is a 'lossy' compression algorithm you'll be throwing away that vital pixel. The truth is that modern JPEG compression – when used with the High quality settings found in modern D-SLRs or Photoshop – is essentially visually lossless if used only once or twice on an image. There is no question that by forcing the choice of exposure, tone curve, and white balance at the time of capture JPEGs limit your options to change your mind after the fact – just like slide film did. But that doesn't mean that slides aren't as good as negatives or that JPEGs aren't as good as RAW files. It means you need to decide on your goals for your photography and about which format fits your shooting needs and style” (David Cardinal, NikonDigital.org).

“While RAW files offer more capacity for change, you can still do a lot with a JPEG file to optimize it for use. I shoot mainly JPEG for professional work because it fits the workflow processes I have developed for myself, and no clients complain about the quality of my images" (Mimi Netzel, Canon EOS 5D, Magic Lantern Guides).

"If anyone tells you that in-camera jpgs are sufficient, tell them to go to the back of the class" (Michael Reichmann).

"Shooting on the RAW setting has become a bit of a status issue, along with ill conceived comments such as, 'only serious photographers shoot on RAW'" (Brian Hall, EOS Magazine).

From the WWW, Forums and Reviews:

"I just noticed the reviewer who was upset that the new Canon G7 does not offer a RAW format. As a professional photographer... just wanted to offer a couple of comments on that subject. In my humble opinion, shooting in RAW format, in many cases, is a waste of time... even in most professional work situations.

"The extra steps in workflow, required by the RAW format, are simply not justified in the majority of photography work situations. I have sold many prints, posters, and stock images produced from jpeg files. I have also been published in magazines and travel books using jpeg images almost exclusively. Many photographers have come to view the jpeg format as the 'amatuer' format and RAW as the 'professional' format, which I believe is really not accurate. I know a lot of professional photographers who make extensive use of the jpeg format (no matter what camera they are using).

"I have not found a photographer or editor, yet, who can actually tell the difference in a print produced from a RAW file and one produced from a high quality jpeg file out of the same camera" (from a review by Joe West, Joe West Photography, with thanks).

“I've also found that for most situations the highest quality JPG is difficult (if not impossible) to pick out from a RAW image on my Fuji S2, EXCEPT under difficult lighting conditions, where the RAW formats options can provide a superior image.”

“There are two primary advantages to raw files. The first is that the white balance has not yet been applied to the image data (on most cameras, at least). If you do not white balance correctly, fixing it later in a raw file is a non-destructive change. In a JPEG you will lose some data as you are actually changing values rather than merely their interpretation. The second benefit, again with many but not all cameras, is that the raw format typically offers more bits to work with than does an 8-bit JPEG. If you need to do heavy Photoshopping on the file, this helps prevent posterization or banding. Otherwise, the formats are similar. A raw file contains no more dynamic range than does a jpeg, just finer resolution within that range.”

“From what I understand, JPEG compresses most over areas of low detail. If you try to pull this detail out or even adjust the contrast over a smooth area, the artifacts will become VERY noticeable. This is much less a problem with higher quality values, but the possibility is still there. Avoid JPEG if you can.”

“…you don't see any easily discernable differences between JPEG and RAW-based images, when seen at a normal viewing distance. JPEG is designed to look just the real thing, where your eye normally doesn't notice all the missing bits.”

“…in my opinion, the greatest value of RAW over JPEG is workflow… BUT the bottom line is, can you really see the difference just by picking the printed pictures up? In other words, you can not walk into a room and say, 'That was shot in JPEG, and that was shot in RAW'."

“[I’m a] photographer professional & semi-professional for 40+ years… unless you examine a finished print at a magnification that no average person would use, it would be very difficult if not impossible to see the difference. I use this as part of an exercise with my students and have yet to find anyone who is able to tell the difference.”

“RAW is the closest practical thing you can get to 'unsullied', when extracting shots from a camera…”

“Shooting RAW allows the educated digital photographer the ability to capture a moment with the most detail and in a way that a jpeg shooter cannot.”

“I photograph 5 to 10 thousand children a year. JPGs make beautiful 16x or 20x . If I want to do portraits I can shoot RAW. If I do schools I use JPGs. I love the versatility. Weddings, JPGs.”

“I just can't seem to get final images that look as good starting with Raw conversions as I can with the JPEGs! ...except for where I have had to rescue one deeply underexposed image, I've been able to make consistently better results from the embedded JPEGs than from the CS Raw conversions!”

“I have several magazines that I work for on a contract basis for doing various assignments. I have also been a press photographer. I use a 10D with a D60 as backup. All I have ever used is large fine JPEG. If the exposure is good, very little work needs to be done to the file. With instant feedback it is a simple process to get a correct exposure. I can see all the RAW purists having fits and leaping forward to denounce me, but I have a pretty good balance sheet showing that my clients are happy.”

“When I first got my 10D I tried both RAW and JPEG and decided that the time factor using RAW far outweighed the gains in quality. Yes there may be gains in quality with RAW, but every RAW converter I used gave different results - none of which were exactly what I wanted anyway.”

“The resultant image from an adeptly edited JPEG can easily look better than a Raw Conversion edited with inferior techniques/tools.”

“…even if you know how to expose your pictures properly, the JPEGs are oftentimes unpredictable in the highlight and shadow area.”

“Another reason for shooting RAW is that a conversion process may be developed sometime down the road that will have the possibility of much better data mining than the current converters, and I'd have the RAW files on disk, waiting to be re-converted.”

“The best reason to use RAW over .jpg is depth of color. You probably know 10D RAW [and 300D] has a color depth of 12 bits, this allows for 4096 shades of red, 4096 green, and 4096 blue. When converted to a 16 bit tiff, it will have 65,536 shades of red, 65,536 green, and 65,536 blue available. .jpg has a maximum of 256 shades of red, 256 green, and 256 blue. There is 16 times the color depth available by using RAW vs .jpg, and another 16 times that once you begin post processing. I feel this is very important if your subject has lots of detail (landscapes for example). RAW compliments but does not replace talent.”

"It is my understanding that there is no such thing as a 'raw image'. The term is an oxymoron. A raw data file can be compared to the latent image on film, after exposure and before development. Depending on how the processing is done (chemistry, time, temperature), contrast and color values in a slide or negative can be changed. But an original JPEG or TIF image file must be compared to a slide in which basic contrast, saturation, color balance, etc. have been set and fixed by development.

"Processing of the raw data by a raw converter like Adobe Camera Raw or Phase One Capture One is to digital raw data as development is to film. Parameters can be changed by manipulating the data before the image is produced. The raw data file only becomes an image file upon conversion, when it becomes a pdf file in Photoshop.

"Ansel Adams was famous for the tonal range of his prints. This was accomplished starting with his exposure of each sheet of film, which was then complemented by manipulation of processing parameters in the lab, all in pursuit of the perfect print. Had he not started with each latent image, his final goals would have been more difficult if not impossible to achieve.

"When you elect to use the camera JPEG option, you preclude the opportunity to make the most of your images because the internal processing parameters are always the same, for better or worse. You may not want or need the extra quality that raw processing control offers, and may consider the advantages of smaller images and quicker results worth the trade. But if quality is your goal, then raw processing is the only way.

“The RAW converters that come with some cameras do nothing but convert; they have no image controls. I would not expect to see noticeable differences between such images and high-quality JPEGs taken at the same time, or find any particular advantage in choosing RAW over JPEG in this situation.

“The current crop of high-end converters include all kinds of image controls. But these are typically set by the user to become the default settings for all images. If these tools are simply used in that manner, the average converted image might be better (or worse) than the average comparable JPEG and the resultant image still does not represent what RAW can do.

“Now, imagine a landscape with bright white clouds on a deep blue sky. Chances are that cloud detail will be burned out if the exposure is averaged across the scene. If underexposed by half a stop (or more), the clouds will be fine but areas in shadow may lose detail. Such shadow details can usually be cleanly recovered with careful use of the RAW controls, before the image goes into Photoshop, and with resultant superiority to a JPEG that can only be corrected in Photoshop. The more adjustments are made in the raw file, instead of in Photoshop, the better the final image can be. This kind of control shows the real advantage of RAW, but it's only as good as the user's willingness to make the effort.

“Finally, overexposed highlights and underexposed shadows can only be saved if the data are still there. Once destroyed, it's lost and gone forever. However, shadows are easier to recover than highlights, so it is better to underexpose (as little as possible) than to overexpose.

“Regarding JPEG quality: The first-generation JPEG that comes out of a good digital camera is probably as good as a RAW file that has been converted without custom adjustment. Such a JPEG can be saved as a reference source file from which infinite copies can be made for correction and printing, just as a RAW file can be saved. The trick is to never save the next generation (a file that has been changed) as a JPEG because it is in the re-saving that compression errors are compounded. If the content of the file is tonally shallow you could probably re-save it as a JPEG numerous times before degradation became visible, but why take chances? Save edited versions in a lossless file format and you won't have to worry about them” (by Leon Vick, with thanks).

“I develop image processing software and have performed in depth studies on both RAW and JPEG formats. Though most would argue that a JPEG is quite limited, using adjustment layers in PhotoShop will allow you almost the same latitude of color, tone, and exposure correction that a RAW image offers. The highest quality JPEG images from most digital cameras (low compression) offer the same quality as RAW images (concerning artifacts).

“You can test this theory yourself by taking a JPEG and a RAW image (same shot) in PhotoShop and setting them on separate layers and using the Difference layer blending technique. Though a JPEG is limited to 8bit and most RAW files have a 12bit depth the tonal range will look quite similar to the human eye (an illusion if you will). A JPEG will posterize faster than RAW (when making tonal adjustments) given similar conditions, but the latitude of the JPEG is much better than most think and the difference between RAW and a JPEG is quite narrow.

“Most people feel that RAW offers a wider range of exposure compensation, but only a 1/3 +- ev adjustment is within reason, beyond that with a standard 12 bit file you are simply compressing dynamic range. The 1/3 +- ev rule can be applied to JPEG images with simple tonal adjustment layers using curves or levels.

“Most prosumer digital cameras hold enough shadow and highlight detail in JPEGs to render this to be true. [If the] truth be told, RAW is nothing more than a purist 'fantasy' if you will. I see nothing wrong with shooting RAW, but in all my research I have found no strong evidence that JPEG is any bit less inferior. Using techniques described above and several other well known and documented procedures I can perform the same workflow on my JPEG that I can with RAW.”