I have a d7000 and a d90. The d7000 seems to exhibit what I call intermittent AF. It seems to have problems when it is zoomed in and I move from something far away to something near. On the other hand it seems to not follow any set pattern as sometimes it will have a mind of its own.
I have tested in a Sigma 18-200.
I had the entire AF part changed and the camera was given a once over. The same problems have surfaced as they were before the so called repair. I was thinking I bringing back to them but am not sure if there is a problem.
Maybe I am just asking too much of the AF.
I put the Sigma on my d90 and it was pretty much flawless.
So what is going on?
I have a job coming up and would like to use the d7000 as my main body but if this is not fixed I can keep it as my backup until this mystery is solved.
#1. "RE: intermittent AF" In response to Reply # 0
Port Charlotte, US
You didn't mention how you have your AF set up. It may be that your AF settings are not optimal for they type of photography you are attempting. While there could be a problem with the camera, a good starting point would be to understand how your D7000 AF is currently configured. AF-S or AF-C, how many sensors, 3-D, etc?
"Red is gray and yellow white, but we decide which is right ....and which is an illusion"
#2. "RE: intermittent AF" In response to Reply # 0
I have a D7000 as well. I have not experienced this issue, but recently read a thread on this site about others that have. Best I figured from the read, the trouble was concluded to be a very slight bump of the lens release button. I have not played with it, but as I understand, even the slightest touch of the lens release button can disable AF. I guess I either have a D7000 that is not that sensitive or I just happen not to touch that button during normal use. Search for that thread and see what you think. There are also discussions in the thread of non Nikon lenses and contact cleaning and other related ideas to resolve issue. If I get time, I will look for it and reply with link.
#4. "RE: intermittent AF" In response to Reply # 0
Have you checked with Sigma re: compatibility of the lens with the D7000? I know that there's several folks here who have needed to get Sigma lenses "rechipped" to work with newer model bodies.
(I have no knowledge about this lens - please forgive me if that's an obviously wrong suggestion.)
Do you have other lenses that work fine on the D7000?
As mentioned, some have had problems bumping the lens release button; others have had to clean contacts on the camera (use a dry micro-fiber cloth first, then try DeOxit); others have figured out that they need to twist the lens into position just a bit more firmly.
#5. "RE: intermittent AF" In response to Reply # 4
Port Charlotte, US
Many of the auto focus issues raised were the result of using the wrong type of auto focus for the required photography. That may be the case or it could be a problem with either the body or lens.
Changing the auto focus type is easy. You need to locate the focus mode (AF/MF) switch on the side of the camera. Inside the switch is a button to change the AF type. Push the button in while rotating the rear command dial to change from AF-S to AF-C, etc.
Here's a decent article that explains the why and when to use the various AF options.