I'm a photographer

It's called HDR (High Dynamic Range). I'll copy/paste what I wrote in reply for every time someone asks me lol:
HDR refers to High Dynamic Range. It basically allows you to photograph a subject as it truly appears, or BETTER in many cases.
The basic principal behind it... I use a Nikon D70s. It allows me to use "Bracket" shooting. I set my bracketed shots for 3 shots, each 2 stops different from the other. This basically creates three photos: -2, 0, and +2. You then use a program, Photomatix in my case, to merge them together. Once merged, it's still nothing special. You then need to use that program to "Tone Map" the new single image. This is what brings out the final product.
You can also use just one imagine, ONLY if it's a RAW image. This helps for you to take photos in diverse conditions (moving vehicle traffic, pedestrians, trees, whatever). You then use a RAW editing program to change the stops manually as with the 3 photo routine. You then save 3 versions of that original RAW. -2, 0, and 2 EV as before. Make sure the RAW editing program does NOT save file info, and if it does delete it. If this is not done, it will not work properly and will look like poop. At this point, you then go ahead and Tone Map as before, and you get a similarly good final product.