Canon xsi will not take photo in too low of light, help

Hi, I have an XSI. I am wanting to take 5-20 second photos of the stars, and other low light subjects. If the light Is too low the camera will not snap the photo. My settings are:
Manual
5" shutter
F5.6
ISO 100
White balance on auto

Your help to greatly appreciated.

Steve

do you have auto focus on?

Yes, switch the lens to manual focus.

Thanks for the help. I switched to manual focus and that solved the problem. Can anyone explain why the camera will not take a low-light photo in AF mode?

Yes, it won't take a picture if it can't focus, it's just how they are set up. In low light the camera can't always see enough contrast to be able to focus, so won't trip the shutter. Switching off the AF means that it no longer tries to focus and accepts that you know what you are doing and have focused where you want.

At the risk of sounding patronising (which I don't mean to be) these sort of things are well covered in the manual, and reading it will give you the heads up on how your camera will behave in situations like this. That way when something happens (or as in this case, doesn't happen) you are more likely to understand why. In addition, you are likely to find new and cool features that are hidden in the menus somewhere that you didn't know your camera had, and get a better grasp on the different modes as well.

sandpiper wrote in post #16955443
Yes, it won't take a picture if it can't focus, it's just how they are set up. In low light the camera can't always see enough contrast to be able to focus, so won't trip the shutter. Switching off the AF means that it no longer tries to focus and accepts that you know what you are doing and have focused where you want.

At the risk of sounding patronising (which I don't mean to be) these sort of things are well covered in the manual, and reading it will give you the heads up on how your camera will behave in situations like this. That way when something happens (or as in this case, doesn't happen) you are more likely to understand why. In addition, you are likely to find new and cool features that are hidden in the menus somewhere that you didn't know your camera had, and get a better grasp on the different modes as well.

Reading the manual...good advice which I have done myself, however I also find that if I don't use the function very often, or at all I may forget how to access it. Sometimes it is easier to ask the question then dig thru page after page to find the info, then again I would probably learn more and retain it by doing so. JMHO

From my days in the Navy ('70-'77): 'RTFB'.