Most people think that it doesn't matter which flash, lens, or film you use. But it does. Here are two pictures, with the same lens and film. The only thing we changed for the second one is we turned off the flash. And the difference is amazing.
Flash-red eye gel
Result: a dark, shadowy, yet bright photo, good for taking pictures of rock bands.
Result: still dark, yet colorful, and dreamy, good for taking photos of the night sky, or a beautiful horizon.