Failure to focus...???

[cab]

Trying my hand for the first time to do some very low light shots of a harbor/bay with city lights reflecting off the water. The D50 (and 10-12 Sigma) on occasion would appear to be having problems focusing (using auto focus). In trying to focus it would also stop me from taking a photo. Its failure to focus would appear to be quite random i.e. taking the same pic it would sometimes be fine and then subsequently ignore me no mater how many times I pressed the shutter button!! ;-)

So what am I doing wrong - never head this problem before in regular conditions

Thanks CAB

PS - In retrospect I guess I could have used the manual focus option....

[mneame]

i've noticed this with my 30d with my canon lenses in low light. always just switched to manual mode. would be interested to hear if there's a method to keep the auto focus in use.

[EmmaP]

The auto focus needs to find something to focus on. In the dark it cannot make out an edge, that's all. I often use manual focus in normal conditions if I'm focusing on something that lacks texture.

[bramley]

I think all cameras will struggle in low light? I carry a torch in my bag and have sometimes pointed the torch at the area covered by the AF point I want to use, and this has allowed the camera to focus. Once I know I've got focus, I switch the lens to MF so that it doesn't try unnecessarily to re-focus.

[m3evo2]

bramley said:

I think all cameras will struggle in low light? I carry a torch in my bag and have sometimes pointed the torch at the area covered by the AF point I want to use, and this has allowed the camera to focus. Once I know I've got focus, I switch the lens to MF so that it doesn't try unnecessarily to re-focus.

That sounds like a good plan. I also use a torch to illuminate the subject but hadn't thought abbout changing to manual focus.

[Mr Noble]

Just read the topic name and though that it sums up my current state perfectally!

[VxDuncan]

Are you using a remote? I had the same issue with the D80 and a cheap IR remote off ebay. Was fixed by using bulb, Manual focus and a new wired remote. the IR remote worked fine in daylight...

[cab]

remote had exactlty the same impact as pressing the button.....