I am wondering how to go about making one shot into HDR. From what I understand, you are supposed to take multiple shots of something at different f-stops and merge them in photoshop, but I am seeing people come up with HDR shots that are single shots, like action shots and stuff. What do I do to make one shot HDR? Do I play with the levels and save the pic multiple times, then open all the saved files and merge? Please, any help would be great, thank you.