I’m a RAW-only shooter, no JPEGs for me in terms of what I keep.
But yesterday I was reviewing images outdoors, zooming in to check focus. I noticed that I could not zoom in all that far, and that there were obvious artifacts visible on subject matter such as small branches against the white background of the wall of my house.
Switching to RAW+JPEG Super Fine, what I found is that not only could I could zoom in about 2X more, there is a complete freedom from ugly artifacts. So from now on, I’m shooting RAW+JPEG (I just throw away the JPEGs when I download).
It’s a big deal because if you are trying to nail a shot, being able to evaluate an image for sharpness is just no good with reduced resolution overlaid with artifacts; it makes it much harder to determine if you nailed focus or not.
The principle here is a general one affecting many cameras: in image review, most cameras show you the embedded JPEG found in the raw file. That embedded JPEG is not only of fairly poor quality (aggressively compressed), it might have less than full resolution too.