Today digital cameras come in all shapes and sizes. I even was recently visiting family and saw a commercial on TV about a camera for toddlers that even after being dropped down a flight of stairs was still fully operational; which would not be the case with mine… trust me I know. And one of the biggest buzz words in regards to digital cameras is Megapixels, how many of those teeny tiny sensors are on the device you are using to take a picture. While the number of pixels is important, the onboard circuitry and file type also play important roles in the difference in quality of the final image. So what is a RAW image?
A RAW image file is the equivalent of a 35mm (film) negative. Now each camera manufacturer does have their own version of a RAW image file; Nikon (NEF), Canon (CR2), Pentax (PEF), Sony (SR2) and so on and so on, as there is no standardized file format. When you press the shutter it records all the available information that the camera is designed to without discarding or compressing any of the data being collected. Each pixel records an amount of luminosity and translates that into color using what is know as the Bayer Filter (a matrix of blue, red and green colors). At the time the picture is taken the camera is also writing to the photo’s file information known as Metadata. This Metadata includes the camera model, date and time, camera settings (exposure, ISO, white balance, focal length and shutter speed to name a few) and even GPS on some cameras. With a RAW image all of this information is what is being saved to your memory card… hence the large file size. JPGs are preferred by some people because of file size alone and that more of them can be stored on a memory card. Why are JPGs smaller?
With JPG, or JPEG (Joint Photographic Experts Group – the committee that standardized the file type) images the initial stages are identical. In fact even if your camera doesn’t allow you to save in JPG format it is still capturing the image in the same way. But the difference is that while a RAW image retains all the luminosity recorded per pixel, a JPG (using algorithms (calculations made by your camera)) determines the most prominent color of the three (red, blue, green) and records the levels of only that color. In RAW format the files retains the information for all three colors per pixel. Another important factor is also the file structure type. Without getting too complicated a RAW image is a 12- to 14-bit image, whereas a JPG is an 8-bit image. So your camera (based on the settings you have made) is discarding some information and compressing the rest. What does this mean to you? Well the smaller more compressed files loose a lot of the fine details of a photo and sometimes inaccurate colors.
Now some people will argue that their JPG images are just fine, in fact look much better than RAW if they are shot simultaneously, which a lot of cameras allow. But you have to take into consideration what those files are. Again a RAW image is a digital negative, where a JPG is what your camera has determined the image should look like according to the settings at the time the picture was taken.
The above image is a screen shot of a mountain top in Colorado taken with my Nikon DSLR camera, in ‘NEF+JPG’ mode. The camera wrote two image files to my memory card after only pressing the shutter once for this scene. While the JPG image clearly shows the cameras white balance and color settings, the NEF reverts the image back to its truest (digital negative) version.
One of the advantages of taking a RAW image (which is what I only shoot) is the ability to manipulate the photo in post editing. For most my photos, if I had the correct white balance, color saturation and other in camera settings correct for the shot) just simply saving the image to a JPG format is all I need to do. But on occasion I’ll have missed a setting, exposed the image wrong, or if I’m looking to digitally enhance the photo a RAW file is better to work with since all the information that was collected at the time I pressed the shutter is still available. If you shoot an image in JPG say with high contrast settings or increased color saturation; and once you get that image up onto a full size screen and realize you don’t like the outcome, it can be extremely difficult if not impossible to go back and fix the image. Even if you work on a RAW image, your program is saving your changes as a separate file… so you can always return the image to it’s original state if you make a “whoops.”
Photography programs, such as Photoshop, these days do allow you to change exposure, saturation, temperature, etc. on JPG files (using sometimes complicated conversions) but again you are only changing what was recorded in the original file based on the settings at the time. With a RAW image your changes are more detailed and exact in post editing, and you retain many of the details of the photo. You also can get artifacting in JPGs, which is the distortion you see sometimes in lines on a photograph where it will resemble the exterior of an Egyptian pyramid. Some of the information I change in editing RAW files aren’t available in JPGs. For example… my dogs are often with me when out taking photos, and white balance and ISO are two settings that I change quite frequently. Say I’m out shooting a landscape sunset and suddenly a Bull Elk emerges from the forest behind me. Before I know it two dogs are going usually in two separate directions and as I suddenly find myself being tangled up in their leashes, the last thing I’m thinking about are camera settings before the Elk runs off into the distance. Shooting in RAW allows me to go back into the file and adjust those fine details to produce the perfect image. No, I still haven’t learned my lesson and just leave the dogs at home.
Aside from file size, the amount of time in post editing work can be another drawback to shooting in RAW format. But with today’s software there are ways to batch convert those images to JPG format as well as apply similar adjustments to a series of photos in batch processing as well. This for me is a huge time saver. For my landscape photography I examine each photo individually, but when I shoot sporting events, those batch processing options can be set and the process can run all on its own while I can be doing something else.
So is one file format better than the other? Well that is up to you!
