NIkon D70s and D100 autofocus not focusing properly

<p>Hi-<br>

I have had both by D70s and D100 for serveral years. The auto focus appears to be inconsistent,(i noticed it the first time I used the D70 new, and with both bodies, and figured it was a characteristic of auto focus) and is getting worse lately. Typically on a shoot, with the D70, the focus is fine for the first 30 shots or so, and then quits focusing. I have tried the different focus settings. I am shooting mostly portraiture ASA 200. It either won't fire (when set to autofocus), or sometime focuses on the wrong part of the subject. Manual focus is fine, but I have come to rely on the autofocus mode. I tried to get the lens, I use the most time (18-70), serviced, and they could not find a problem. It happens with different lens. Any ideas?</p>

<p>thanks<br>

BA</p>

<p>Couple of quick thoughts, I had a similar problem with my 70s a while back, I sent the body to Nikon for a cleaning a calibration. This for me seemed to solve the problem. I have also noticed on my D300's when the battery starts to get low (well before the indicator indicates low) the autofocus starts to drift and the images become less sharp. I change out batteries now when the indicator moves to the right just one bar and that issue is gone. Maybe thats why your first 30 pics seem to be fine...</p>

<p>Yes, it could be a battery issue. If your batteries are as old as your cameras, their discharge profile will have deteriorated, and voltage will start to drop more quickly instead of holding up right to the "battery discharged" indication. This could affect the autofocus operation, especially on the D70. It might be worth investing in a new battery.</p>