shutter/focusing problem question

[Cathrine]

Hi, I'm hoping someone can help me. If this is the wrong area, I apologize. I bought a Canon t1i a couple of months ago and I love it. I have a question/problem that I need help answering about it.

A few nights ago I attended a firework show. Obviously it was dark and I wanted to take some nice pictures of my kids watching it. My mother's boyfriend is a professional photographer and he told me to stay at the ISO 100 as much as possible as well as use the flash. Well, I was boundly determined to stay at ISO 100 and I kept forcing my camera to take pictures. It was making loud shutter (click click click) sounds like it was trying to focus and wouldn't take pictures at times.. I eventually increased the ISO to 1600 and it was better. But, I was still making those shutter noises (click click click noises) at times.

Today, I decided to go outside and take some pictures of flowers. It was late afternoon, ISO 100, 50mm lens, I used varied aperture... I was on AV setting. As I was focusing on a particular flower among a bunch of flowers, I got those shutter clicking noises again like it was trying to take or focus but couldn't. I changed my metering to spot metering and it didn't really help much.

What am I doing wrong?

Thanks so much!!

[Nicole]

If it was dark, your camera might have been having a hard time figuring out what to focus on. With the flowers, it could be that there wasn't enough contrast for the lens to easily focus or you were too close to the flowers for the lens to be able to focus.

Things to check would be:
-Check to make sure you aren't closer than the lens can focus
-Check to make sure that there is enough light that your camera can tell what you're trying to focus on (e.g. try shining a flashlight on a subject in the dark and you'll see how much easier it should be to focus)
-Check to make sure there's enough of a contrast for the camera to figure out what you're trying to focus on (e.g. if you're trying to take pictures of white flowers on white snow, your camera might have a hard time figuring out the focus)

This article might help a bit too: Understanding Camera Autofocus

Changing your metering won't help with getting things in focus, rather it tells your camera how bright / dark a scene is.

[wmdjameson]

Try flipping your lens to manual focus and see if it still does it. If so, it's more than likely a camera issue. Alternatively, put on the 18-55 and see what happens. Also, try moving a few feet back and test it out again. Another question, what do you have your AF set to in the camera? Try setting it to AIServo

[Vagebond]

You didn't mention it, so have you tried changing your autofocus point selection from all points in the grid to a single point?

I read somewhere that the centre AF point is the most sensitive to light/contrast, so I suppose that would be the one for low light.