Shooting the feeding of a walrus at the zoo recently I encountered some really tough light: direct sunlight on the background with dim and very blue lighting from the sky on my subjects. At first I attempted to shoot with natural light, but then gave up and then resorted to the dreaded direct, on-camera flash. But my best frame was an early one, so back at the lab I had to spend about 40 minutes rescuing the frame with PhotoShop work.

Here's the before and after:

These two versions reminded me of other examples of the dramatic improvement that can be wrought. Here's another example where I spent about 40 minutes in PhotoShop rescuing a shot with really bad lighting:

There was no practical way to set up good lighting on the ski slope, and it was just bad luck the the sun had to be upslope.

And here's an example where there wasn't much "heavy lifting" to be done in PhotoShop, but careful use of "shadows/highlights" and "unsharp mask" made a big difference in a shot with easy lighting:

And keep in mind that it isn't the particular program-- Adobe PhotoShop-- that is essential. There are several other photo editing programs that can be used for this kind of work. PhotoShop is merely the Cadillac version (and us news photographers only use about 10% of the features in it).