You might have heard RAW files being mentioned when you were sold your camera. You probably shoot jpegs. However, many cameras today can shoot RAW files, even some of the most basic compact cameras. Most serious underwater photographers shoot RAW files rather than jpegs, or they shoot both concurrently. So what's it all about?
When you shoot a jpeg, the in-camera processor uses an algorithm to save the picture in a file form that is compressed and doesn't take up much space on the memory card. If you can set your camera to record RAW files, the memory card records everything that is picked up by the camera's sensor. It means that instead of relying on an algorithm written in some far off part of the world, you can manually translate your picture using your home computer later.
On the left is a picture that equates to what would have been recorded as a jpeg at the time. It's not very good, is it? The photographer had his camera set incorrectly and would have had to have adjusted his camera in a suitable way to get a properly exposed shot.
The contrast is too high, the highlights have burnt out and the subject is disappearing into the background.
If you look to the right of the picture you will see some controls. This is the original RAW file displayed on the screen of a home computer (PC or Mac) using a proprietary RAW converter program. The controls on the right have sliders that can be adjusted for colour and hue, exposure, contrast, highlight detail, shadow detail, whites and blacks, clarity, vibrance and saturation.
Now given time and a co-operative subject, the photographer may have been able to adjust his camera and flashgun to get a similarly acceptable jpeg but this is done at home long after the dive is over and without the time constraints caused by being underwater. Here's a close-up view of those controls:
Now you may prefer the instant gratification of getting it right in camera but what if the subject is not co-operative. What if it's a moment in time that you have just managed to grab. Maybe it's an image of a fast-moving shark that happened to come close to your camera for a moment.
You won't have a second chance. You may still have your camera set for the previous picture you took. You just press the button and hope for the best.
If you have shot a RAW file you will have the option to decide on all the camera settings, save for focus, long after the event.
Not only that, but there are layers and layers of controls, some of which are quite advanced, but there is nothing difficult about using them. You just move the sliders about until the result looks satisfactory to you on your computer screen. A histogram helps make sure you don't overdo it. You cannot damage the original RAW file. You have that safely stored.
A good friend of mine shot a picture of two dolphin. He was over-the-moon with the result and sent it to me. I thought it was so blue it was monochromatic but he was happy because it reminded him of the moment. He still remembered the colours and they were still apparent to him. They were not to me.
I asked him if by chance he had also shot a RAW file. Luckily he had although at that time he didn't know what to do with it. He now knows! Once he saw the difference and once it was explained to him how easy it was to convert the RAW file in an adjusted way, provided he had the right software and plug-in to suit his camera file, he too was converted!
As iconic underwater photographer once said, if you are not shooting RAW files you are missing the point of digital photography.