I'm fascinated by long exposures. Created with the "bulb" feature on most modern SLR's. I started experimenting with it and am getting the hang of the camera through trial and error and study.. Since the shutter is opened as long as you have the button pressed what do you do about aperture? How do you use it for something like the "bulb" or does it really matter? Also some quick questions... Is depth of field simply how sharp point A to point B are in the shot? And the aperture is the amount of light that reaches the film? I'm still trying to get the hang of shutter speed and aperture and how they work together...is there any easy way to understand this? And in fully manual mode, you can set both manually, but I do know that they go hand in hand to create exposure...is there some kind-of formula that you would od in fully manual mode to get proper exposure? I might just experiment to see what works and what doesn't... Thanks!