I've been trying to take some long exposure shots at night with my Canon 450D. The problem I'm having is that I can't seem to get a shot in focus. The low light conditions prevent AF from working at all, nor is there enough light for me to get the focus correct by hand. I've tried through the viewfinder and the LCD, but they're both so dark I can't tell if I'm in focus or not.
Perhaps this is a lens issue? I have the 18-55mm ƒ/3.5 kit lens and the 50mm ƒ/1.8 EF lens; neither of them have focus markings, so I'm not sure if I'm hitting ∞ or if my lenses are even capable.
Thank you very much for the suggestions. I’m not able to shine a light, as I’m hoping to get landscapes and night sky shots, and I don’t have anything powerful enough to reflect back. I tried focusing with the 50mm ƒ/1.8 wide open, but I couldn't see anything. I don't think lens speed is going to make a difference.
It sounds like trial and error is my best shot here, which is unfortunate.
Side note: It sucks that the 450D has no way to display the focal length. This info is recorded in the image metadata, so it would seem like it should be available.
I have two more options that I came up with:
Set up during the evening, when there is enough light to focus, then take the shot at night. Potentially impractical due to time, but I see no reason it wouldn’t work.
Use another camera. I tried again with my PowerShot S90, and got significantly better results. I was able to manually set the focus to infinity, and the wider angle / smaller sensor meant that I didn't have to worry as much about depth of field causing blur. While the S90 only allows for 15s exposures, CHDK removes that limitation.