Lightning

arctic98z wrote in post #14817722
I do have one question though, what effect does aperture have while in bulb mode? Is it strictly for depth of field or is the amount of light hitting the sensor effected as well? I have a decent understanding of how the camera works in general, so I apologize, I'm not asking the newb 'how does this work question.' I ask mainly because I tried to experiment last night with different aperture settings and didn't really notice a difference.

Aperture, in any mode, sets the depth of field and determines the amount of light hitting the sensor as well (since it is a physical opening). The f-scale tells you how open the aperture is. For example, f/2.8 is a large aperture for a lens, and hence why they call it a "fast" lens since you can take a very short exposure. On the other end, f/22 is a very narrow aperture and will allow for much longer exposures. In fact, f/2.8 to f/22 is 18 clicks (in standard 1/3 notation), and is hence 6 stops of light (3 clicks=1 stop), or a factor of 2^6=64 in exposure length (depending on whatever aperture you are measuring from). Hopefully this is not more than you were asking for

As for not being able to tell a difference in depth of field, I'm not surprised. Typically, night photography is shot at lower f/#s as to maximize the light. One of those exceptions is lightning photography. You most likely set the focus manually. Where did you set the focus? I would guess at/near the infinity mark on the lens. Depth of field tells you how close to the lens things in your shot are sharp, and then how far beyond your lens objects are acceptably sharp. If you are focusing at/near infinity, your depth of field won't appear to change much no matter what f-stop you choose.

One last thought: the higher the f/#, the more an isolated light source will appear to "starburst". Lightning has a fill-flash effect, so you won't see this happening.

Hope this helps.

John