Understanding RAW Format

by

Alton Vance


I'll start by explaining where RAW format comes from.

All digital cameras take their original image in some kind of RAW format. RAW files are usually proprietary to the camera manufacturer and sometimes to the specific model of camera. That means, only the camera that takes the picture can understand the information collected on the camera sensors. That information is then translated by means of firmware (software) built into the camera and the usual result is a more user friendly format called JPEG. That is why most cameras produce images with an .jpg extension. JPEG is a compressed format (and has the ability of varying degrees of compression). JPEG has become a fairly universal digital standard for photo images.

What happens is that all digital cameras use firmware to apply various qualities to the RAW format before it is written to the memory card in JPEG form. The firmware in the camera will apply varying degrees of sharpening, varying degrees of saturation, varying degrees of contrast, etc. Most cameras have facilities to change these settings to the photographers liking. The only hint you have of what that photo will look like is the small LCD on your camera. This is usually too small to tell enough to make changes until it is too late. Often the photographer doesn't want to mess with those changes on the field anyway. So you set your camera based on the last experience. Many people never experiment with changing these settings anyway.

Thus enters the advantage of shooting RAW. The RAW information settings can be set in the software after you get the image home or downloaded to your computer where you can see the image on your large computer screen before you develop it into JPEG. There are two RAW software publishers (which I discuss below) that I use and I'm sure there must be others of which I am unaware.

Adobe Photoshop CS (the latest version) now reads RAW format for many late model digital cameras. PHASE ONE publishes RAW format conversion software called C1 for most (but not all, though they continue to upgrade quickly) professional and prosumer cameras.

Many digital cameras still do not give you access to the RAW format so JPEG is your only choice. I prefer C1 for its workflow ability over Photoshop CS. For me C1 is better for mass development (when you have a lot of files to work with). However I use Photoshop CS when I have just one or two files to work on because it is convenient to have the file in Photoshop for further processing if desired. I have noticed that each of these titles give somewhat different results in development. You might prefer one over the other but if you already have Photoshop CS you probably won't want to invest $99 to $500 in C1, (it comes in various version with different features but quality is the same in all versions). However if you are still using an earlier version of Photoshop, a reasonable decision would be one of the lesser versions of C1. http://www.phaseone.com.

Both of the software packages above allow you to adjust exposure settings by plus or minus two stops. This can be one of the biggest advantages of shooting RAW. You can make adjustments, as slight as it may need, as if you were doing it in your camera at the time of exposure. (Although I do recommend an accurate exposure at the time of shooting. That will still result in the best deatail.) Also you can adjust settings for saturation, contrast, sharpness, white balance (another wonderful feature of RAW and perhaps the one that makes the biggest difference) etc. just like the settings in your camera would have done, but now you can adjust it as many ways and as many times as you want for each picture and see what's happening with each adjustment before it is developed.

A RAW file might be considered similar to a film negative with adjustments.

One big disadvantage of RAW files: they are large and take up 2 to 4 or more times the space of JPEG files, depending on the compression choice you use in JPEG. So keep in mind your storage space when making a decision to use RAW.

When making a choice to use RAW files there are three other things to consider.

Number one: RAW files cannot be saved back to RAW once they are converted to JPEG. The advantage of that is your original RAW file is never changed nor is any information lost in compression because you cannot resave to the original file. So your original information is always left intact. I understand that every time you save over an original JPEG file it is further compressed each time you save it. If you loaded, edited, resaved, closed then opened, edited, resaved, and closed a JPEG file 100 times you would see considerable degradation in the resulting file. (The solution to that dilemma is to always rename your file so you do not save over the original JPEG.)

Number two: If you need to save space you can always delete your RAW files after you have arrived at your best settings and converted to JPEG. Personally I like to choose my best shots and keep the best RAW files and save over my JPEGs. If the JPEG gets degraded I can always go back to the original RAW file and develop again from the original information. (However keeping my RAWs may mean buying a larger hard drive or two down the road.)

Number three: It takes considerably more time to develop RAW files than to have the JPEG already finished out of the camera. It has taken my son quite awhile to see the advantages of RAW solely based on this fact alone. It is just too much trouble for some people. For me it lends versatility.

I do not in anyway pretend to be an expert in RAW file development but I am sharing my personal experiences over the past 1 and 1/2 years. Since the day I bought my Canon 10D I have rarely (and then only accidentally) shot in straight JPEG. (I have shot more than 8000 images in that period of time and have developed most of them from RAW.)

There are professionals who shoot in RAW. There are professionals who shoot in JPEG and both do wonderful work. It is somewhat a matter of your preference, your time, your space, and your desire or need to have the extra flexibility of RAW format. My son shoots and works for Michael Shaffer Photography (http://www.schafferphotography.com/) and they still shoot most of their work in JPEG. I am the amateur hobbyist who can take the extra time to work with RAW. I don't have deadlines to meet.

I hope this is helpful. I also hope it is somewhat accurate. Thanks!