D200 AF problem

Hi All,

I experience a problem with the AF of my D200. When i use my 105 VR or 50 mm Sigma and try to focus on a subject it starts to hunt. If it doesn't find anything on it's way it just focusses closer untill it reaches its closest focus. When that happens it just refuses to focus backwards and it blocks completely, the only way to unblock it is by switching the focus to manual and release it by hand. I was allready in the camera shop and i tried it with a 60 mm Nikon as well and the problem still persisted. Also switching from 'S' to 'C' doesn't make any difference. Switching 'on' and 'off' the camera also doesn't solve the problem. With my 105 i fortunately have a focusgear but my 50 mm is pretty useless UW now....

When i try the same with my 10-20 mm WA or 10.5 mm FE there isn't any problem at all: i can get it to the closest focus and if i then aim at something further away there is still enough contrast for the AF sensor and it just focusses normally.

In the shop they initially thought it was problem for Mr Sigma, but since it does the same with my 105VR and also with a brand new Nikon60 mm they suspected it to be a D200 body problem. They never heard about this problem and they recommended to contact Nikon support for this problem.

Is there anyone in the forum that has experienced this (or something similar) as well? Off course I'll contact Nikon but off course they won't reply before monday... I'll keep you people informed, when there is news

Udo

Udo,

don't know if it'll help but I had a similar problem with my Fuji S2 and my 80-400 where the focus would get locked at minimum forcing me to manually release it. I tried the lens on my D200 the next day after pulling it out out of the housing and the same thing happened which led me to believe it was a lens problem.

However, it only happed for a few days while on vacation in Florida after dema and hasn't happened again since. The only variable I could come up with was that the weather was quite cold and humid at the same time. It was florida so it wasn't snowy winter temps, but it was surprisingly chilly and moist. Perhaps this caused the problem, but I haven't had it since, so I havn't sent any gear off (and doesn't get so cold here in Bermuda). Yours sounds much more serious though.

The only thing I would suggest is to give the gear a good cleaning - optical elements, lens contacts, sensor etc. first before sending it off. Hope it works out. Cheers,

Chris

Use 3yr old 105 and 60mm on two D200s and never had this problem. The 105 in dark conditions does spend time hunting but works much better than it did on my D100 bodies. Good luck.

The only thing I would suggest is to give the gear a good cleaning - optical elements, lens contacts, sensor etc. first before sending it off. Hope it works out. Cheers

Hi Chris,

It seems that you experienced something similar. But with you it was in humid conditions etc. Over here it was raining yesterday but not extremely or so. Nevertheless i followed your advice and cleaned all contacts of the lenses and the camera body. And guess what: it worked again for a while. But later the problem was back... ... So i cleaned again and the problem persisted. I decided to remove the battery and the CF card and leave everything open for a while close to the heater (not too close off course). And guess what: it worked again... Today i went diving with it (with 105 +6T) and i didn't experience any problem. I don't know how long it will keep on working but at the moment things seem to be fine, keep fingers crossed... Let's see what the service people of Nikon will tell me..

Udo

Hi Udo,

Fantastic. Sounds like the culprit may have been some sort of humidity or moisture getting into the camera. Makes sense, cause the air was very moist when it happened to me. fingers crossed indeed...

Cheers,

Chris

OK, here's an update on how the story continues:

After the first dive i described before everything worked fine, but once back at home the troubles started again. Sometimes it all of a sudden stopped working. Switching on and off a few times, waiting for a few minutes and replace lenses a few times and then sometimes it worked again. So i decided to send my camera to the Nikon Service Repair centre, just before my body wasn't having warranty anymore (i have it for almost a year now).

It turned out that my AF sensor was dirty so they cleaned it. I have my camera back since last monday and so far i didn't experience any problem with it anymore. Keep fingers crossed!!!

But my question is: How can a AF sensor become dirty? Where is it positioned in the camera? Can i probably clean it myself next time? And if the AF was dirty, why was it covered with the warranty, because i suppose that it wasn't dirty when i bought my D200? Not that i complain about that BTW!!

Best, Udo

Hi Udo,

what kind of AF-Measuring mode did You use, single, dynamic, AF-groups or dynamic with short distance priority (don't know the correct english terms ). Or did You already tried them?

I don't know the problem You decribed (Camera completely blocked after AF hunting).

But I also have AF problems when I try to take short ditance shoot's of low contrast objects with my D200.

And in these situations I have the best results with dynamic AF with short distance priority.

Regarding dirt on the AF sensor ..... no idea. But fine when it works now.

Stefan

Hi Udo,

 

what kind of AF-Measuring mode did You use, single, dynamic, AF-groups or dynamic with short distance priority (don't know the correct english terms ). Or did You already tried them?

 

I don't know the problem You decribed (Camera completely blocked after AF hunting).

 

But I also have AF problems when I try to take short ditance shoot's of low contrast objects with my D200.

 

And in these situations I have the best results with dynamic AF with short distance priority.

 

Regarding dirt on the AF sensor ..... no idea. But fine when it works now.

 

Stefan

Hi Stefan,

I had the problem in all AF modes and both in S-focus and C-focus. But normally i use my D200 allways in S mode. But fortunately, i didn't experience anything like it anymore. Yesterday i even used an 1.4X teleconverter with my 50 mm in very bad visibilty concentration (<1 m) and it still worked! So the cleaning of the AF sensor worked.

Is there really no one who knows where to find the AF sensor in my camera?

Best, Udo