Your professional camera probably has multiple settings for RAW compression. Changing how your camera compresses RAW files can be useful for saving space while shooting, but it may have some unfortunate effects, particular if you are using an older camera with an older sensor. You may not notice it in every image, but there may come a time when an important image suffers due to how your camera handles RAW compression.
RAW Compression Settings
Whatever you do, don’t bother with Compressed RAW images, as they will sometimes give you an unfortunate dithering or gradient in your sky shots (or any shots that contain large areas of solid color) that you can’t easily remove in post processing.
As you might be able to see in the above photo, compressed RAW files give “arc banding” with some lenses. This happens when the camera has to deal with the natural vignetting of the lens and tries to compress the gradual changes from dark to light. It does a poor job of this and the result is banding in the image.
There’s also no need to set your RAW files to Uncompressed, that’s a waste of space for all but the most extreme shooting conditions.
The “just right” setting is Lossless compressed. It will keep your files relatively small but you won’t deal with any compression artifacts such as color banding.