Modern camera sensors are amazing feats of engineering. The enormous amount of detail they can capture is often more than can be displayed; because of this, there is a tendency to think the extra data is redundant.
This is not true, as cameras can save all of that extra information in the RAW file for later use. When saving to a compressed format, such as JPEG, all of this information is discarded, and the RAW file is developed with fixed, and often incorrect, information. With a RAW file, the extra information is kept, allowing you to adjust your images long after you’ve taken them.
(If you’re wondering what RAW is, circle back to this article: 19 Essential Photography Terms That All Beginners Should Learn)
Here are three options RAW files keep open:
1. White Balance
White balance is a notoriously fickle part of photography. Lighting conditions can vary rapidly, and a photograph with the wrong setting can suffer greatly.
The sensor itself, however, only sees light. All the white balance information is applied after the shot is taken, and if one shoots in a compressed format this is baked permanently into the file.
A RAW file, however, is just the raw sensor data: the white balance settings can be freely changed before they are applied. Not only does this mean you can rely on the auto setting for previews only, it means no more ruined images because of mistakes or changing light.
Most editing software allows you to select a point of white in the image, and the white balance is automatically perfect. Failing that, it’s very easy to set by eye. Not to mention the possibility for creative adjustment!
A screen can only display a range of brightness which is far smaller than a camera can pick up. Displaying all of that range on a screen makes most images look flat and boring.
To increase contrast, only a portion of the available information is used: two points are set – one as absolute dark, and one as absolute bright – and the image you see fits in-between. Unfortunately, anything exceeding those points is lost to clipping (large patches of solid white or black on the screen).
All of that ‘invisible’ data is lost on converting to a compressed file, yet it still exists in RAW. This means when an image clips, it can often be rescued. Being able to adjust the contrast after-the-fact makes the photography itself faster and more engaging.
3. Contrast and Sharpening
Contrast and sharpening are also baked into any compressed file. Unlikely many camera settings, correct use of these vary incredibly from picture to picture and often require very fine adjustment.
This is simply not practical with an actual camera in the field, often with a very small preview screen. Someone using a compressed format would have to capture an image, then zoom in, panning about the image, before re-adjusting their settings and trying again. He or she would need to do this for each subject they photograph, for optimal results.
Again, RAW files come to the rescue, rendering both of these options easy to adjust with real-time previews, turning a frustrating experience into a single shot.
RAW files take time to develop – but far less time than setting adjustments in the field. The only point against them is the file-size, a very debatable benefit with today’s memory technology. There really is no reason not to use them…. except when…