Tips and Tricks for focusing at night?

[89coupe]

Can anyone give me some advice for focusing at night? Last night I was shooting that pano of the city skyline and about half my photos were out of focus.

The first round I just used the center point and F11

The 2nd round I decided to use AF and F11, I seemed to have better luck with this, but still some were out of focus?

Any tricks to getting it tack on everytime?

[Mitsu3000gt]

Have you tried live view and manual focus?

Are you still hand holding? Is your shutter speed high enough? If not I'd suggest a tripod.

The selected aperture shouldn't have any affect on AF performace as the camera keeps the lens wide open for AF and doesn't stop down to your selected aperture until you take the shot. That said, unfortunately the 50D only has f2.8 support using the center focus point so if you are using a f2.8 lens, focus performance will be improved only by using the center point.

I also assume you are not using continuous AF, but this wouldn't matter if you're using a tripod.

[89coupe]

Originally posted by Mitsu3000gt
Have you tried live view and manual focus?

Are you still hand holding? Is your shutter speed high enough? If not I'd suggest a tripod.

The selected aperture shouldn't have any affect on AF performace as the camera keeps the lens wide open for AF and doesn't stop down to your selected aperture until you take the shot. That said, unfortunately the 50D only has f2.8 support using the center focus point so if you are using a f2.8 lens, focus performance will be improved only by using the center point.

I also assume you are not using continuous AF, but this wouldn't matter if you're using a tripod.

I'm using a tripod, and a 2.8 lens. I haven't tried live view or manual focus. I find it very difficult to manual focus at night.

These are long exposures, around 25sec.

[quazimoto]

It wasn't by chance where the saddledome was in the picture was it? What I do for long exposures, and I mean long exposures, aka 2-5 minute exposures is let the camera autofocus on the given spot you want, then switch it into manual focus. For the buildings it should work pretty good. You might need to play around a bit when doing pano shots though since the focus might change ever so slighly on some shots.

I've had to do this for a number of landscape shots where the neutral density filter I use is something like 20+ F stops and its always worked well for me. The big key is not touching the focusing ring at all though