I took the above photo a couple of weeks ago on a day when the water was fairly stirred-up. It's a pretty good action shot of an octopus "jetting" from one coral head to another. This is a hard shot to get as it's impossible to anticipate when the octo is going to demonstrate this behavior. So, I have a decent shot of an animal doing something that is difficult to capture. But the photo is seriously compromised by all the white blobs of backscatter. Plus, there is quite a bit of "dead" space above the octopus.
Now here is the photoshopped version after tediously removing the backscatter as well as cropping, sharpening and adjusting contrast. I think it's a big improvement. Some people would argue the "integrity" of using a computer program to enhance a photo. But, back in the days of film, photographers would regularly employ darkroom techniques to manipulate their images for more pleasing outcomes. I see no difference except photoshop is easier and produces better results. Also, I don't use photoshop to add things that weren't there or to give a false or exaggerated impression of the marine life I see. I merely use it to "clean-up" a messy image. It's been said that photoshop can make a good photo better but it can't make a bad photo good. I agree.