Here's an example of how Photoshop can rescue a bad image.
Here are three shots of the 765 spotted in Northwestern Station back in 1983. The original film was a 35mm Kodachrome slide. The photographic situation was a difficult one. The sun was shining in the morning sky, but the 765 was spotted in deep shade caused by the nearby buildings. The contrast range (the range from the brightest element in the image to the darkest) was beyond what a digital scan could handle in a single pass, but it was not beyond the range of the film! When I examined the slide with a magnifying glass, I could see that the shadow detail was there. I just had to dig it out. Grant Geist took this shot and he had exposed the film perfectly.
Here is the original scan. In order to properly scan this slide so the bright morning sky was properly exposed, all the shadow detail was lost. You cannot even see the 765. Also note the keystoning of the buildings. Willis Tower appears to be leaning to the right. This is caused by the wide angle lens used to shoot this shot, and the fact that the camera was tilted up slightly to compose the shot.
This is a second scan of the same slide. On this scan I set the scanner to overexpose the slide to bring out the deep shadow detail that was present in the film. But now that gorgeous blue sky is all blown out to white. And the building is still leaning.
Here is the final result. I combined the two scans in Photoshop to make this composite image that shows everything. And, thanks to the Photoshop "Distort" tool, the building is now straight.
This is just one little thing that Photoshop can do. It is an amazing program for photo work. I use it almost every day. I'll see if I can dig up a few more examples.
