[milobars]

Hi there ... I have had a D70 for about a year now ... and overall it is an excellent camera, except in one regard (which I think is the most important) it's auto-focus. Is the focusing done by the camera body or the lens attached? It doesn't seem to matter which lens I have on the camera, but in dim light the autofocus has a horrible time trying to get a fix. Sure the new software does improve on this ... but it's got nothing on my first F60. Has anyone got any thoughts on this.

(I'm not shooting white walls or blank backgrounds ... just ugly faces at parties)

Milobars.

[Petographer]

Hi milobars. Welcome to Shuttertalk. I haven't got the D70 but even my Drebel will have difficulty focusing in very low light conditions. I think it may just be the nature of the beast.

[adam]

Hi Milobars.
I, like Petographer, am not a D70 user, but I guess that autofocus would work in the same way between cameras.
This website explain how it generally works:
http://electronics.howstuffworks.com/autofocus3.htm
And explains why "Passive autofocus must have light and image contrast in order to do its job."

I think focusing is done by the camera body, which then will drive the lens.

[slejhamer]

In my experience, the lens makes a very large difference in the camera's ability to autofocus. On my 10D, I've found the Canon 50mm f/1.4 does much better than the 50mm f/1.8, my Sigma 18-50 f/2.8 does much better in low light than the Canon 17-40 f/4L.

Which lenses are you using?

[adam]

From this, I deduce that larger aperture lenses allow more light in thus assisting the autofocus (which requires light).

['S']

Hi, I just got back to this forum from elsewhere amazing how these things happen, a few changes since my last visit, but thats good. Anyway spotted this thread and it reminded me that a friend was having a similar problem with her Fuji S2, she was about to upgrade, but it turned out she had the focussing set on continuous and when it was put back to the default focus priority all was well. Frankly if you are using it at parties with flash, I would have thought the focus assist light would have helped, but maybe you have only been using available light

[Petographer]

Hi Stephen. I don't believe I've had the chance to welcome you yet. So, welcome! Anyway, I'd have to agree with you in regards to the assist light. I personally never use the cameras built in flash. Sometimes I wonder why cameras even have one.

[shuttertalk]

Milobars - you could try setting the AF zones to use only the centre zone, and place your subject dead centre when pre-focusing. I found that helped with the accuracy with my SLR, as you eliminate the possibilities for other subjects in the frame competing for focus.

Hey 'S'... welcome back! Don't make it too long between visits!