@Msmoto

You are probably right, off to Nikon it will go, and thanks, the D90 is the wife's, I bought it for her a few years back. My collection has grown, I love my D3, and the D300s's are such good versatile bodies that I use all the time. The D3 kind of replaced the D700

I checked with Nikon and its a $199 charge without parts(if needed)

@tcole1983
It will just keep running(motor), running the focus in and out but never lock on. It does work in Manual and I can get a sharp image using M. That lens is kind of a staple on that body, I usually only use that lens and a 50mm f1.4(rare occasion the 70-200mm f2.8 gets mounted to that body). I know it's a less expensive lens but I try to take care of all o my equipment an it's just frustrating.

@ VITAL277

Nice collection of bodies....unfortunately as has been suggested it would appear to be a lens issue. My guess is something has come loose internally or some other internal issue.

And, as one can find some used ones for about USD $200 on eBay. the cost of repair may be too high to be worth it. On the other hand, if Nikon refurbishes it, you will have a new lens.

No idea...sounds like it needs to be sent in though. Does it actually try to focus? As in it tries to focus and just never locks? And this always happens...no matter what? When you manually focus can you get a sharp pic?

I have the Nikkor lens listed above. I will not lock on to anything, the motor will run the focus to both ends of the spectrum until you release the button. The AF Switch is set to M/A and not to M. The Focus Mode Selector on the front of the camera body is set to S, (I have tried in C as well). I have read some other threads on the net that state the retainer clip for the front glass may be loose, mine is tight. I have also seen that they have stated that one of the 6 screws may be loose, mine are tight. Just curious if anyone may have a fix or may have had this issue?

Contacts have been cleaned on the Lens, this lens stays on a Nikon D300s, I have tried it on my D90, D700 and D3 and it does the same thing on all bodies. Lens/Camera have not been dropped/Banged on anything(I'm sure it has been bumped across something).

Any thoughts?

When fully extended ,this lens is quite fragile and the internal focusing easily damage by a knock

so it may be a trip to your local repair station

@msmoto, thank you, I had already searched the forum and read this thread. It didn't pertain to the issue I was having as it didn't matter if I was at 24mm or 160mm it still won't find focus. Still doing research on it looking for info.

Thank you for the quick reply :)

18-200mm f/3.5-5.6

VITAL277 said:
I have the Nikkor lens listed above. I will not lock on to anything, the motor will run the focus to both ends of the spectrum until you release the button. The AF Switch is set to M/A and not to M. The Focus Mode Selector on the front of the camera body is set to S, (I have tried in C as well). I have read some other threads on the net that state the retainer clip for the front glass may be loose, mine is tight. I have also seen that they have stated that one of the 6 screws may be loose, mine are tight. Just curious if anyone may have a fix or may have had this issue?

I had this lens out shooting some pictures at a cookout this weekend. The people were far away and to me it seemed like there was plenty of contrast between the people and the background and it wouldn't shoot. It is weird because it only happens every so often. A picture I took right before and after with similar conditions were fine.

I have thought about sending it into Nikon to have them look at it. Might be something they could calibrate or whatever. I hate to spend the money on it though.

I had this issue before. But I don't think I could focus OT manually either to infinity. Basically the fix was to take a micro fiber cloth and press firmly against the front element and then turn to basically tighten it back into place a bit. Then I could autofocus to infinity again. Seems this lens is just not built as well as some of them...

Funny coincidence but I had a frustrating time with my 18-200 and D60 about three weeks ago - could not get it to autofocus for 15 frustrating minutes trying to snatch images of dragonflies at the 200mm setting. The answer ? Remove and refit the lens. This lens practically lives on the camera so i expect a little oxidation built up on the contacts that needed to be wiped away. All back to normal. Your problem sounds more involved sorry to hear.

Best of luck.

I never really fixed it...I just deal with it. I just know that every once in a while I have to manually focus it a little to get it to shoot. I don't notice as much now and I did back then, but I have started using other lenses more and more. I will say I never have the same problem with any other Nikon lens...it seems unique to this lens.

Hi there,

My Nikon 18-200mm has exactly the same problem like yours since the past weeks. What did you do to fix it? Please advise. Thank you!

Coug

PB PM said:
Your camera does not seem to fall under the list of cameras Nikon has listed as having problems with the 18-200mm VRI. To be honest I'm not sure what is wrong with the focus in the picture you posted, it looks fine, even in the larger version on flickr.

Every AF-S lens I've ever used allows some space beyond infinity. This happens because infinity focusing distances is supposedly effected by temperature.

The problem I had was I could not get it to take that picture for anything unless I manually moved the AF ring myself. It would not lock in AF mode to let me take the picture. Once I manually move the ring past the infinity mark (while it is still in AF mode) then it turns red and lets me take the pic. I don't think it is out of focus, but it is annoying and frustrating when I think it should be AFing by itself and even when recomposing and trying it again it still won't lock. It doesn't bother me that the AF ring moves past infinity, but it does bother me when the came won't AF and lock so that I can take the pictures without manually moving it.

So basically the camera knows where it wants the focus to be, but it can't get to that slightly past infinity without me manually moving it to that point. Once I move it there it locks and lets me take the picture.

PB PM said:
50mm F1.4G is an example.

Hmm... ;)

50mm F1.4G is an example.

PB PM said:
That doesn't explain AF-S lenses that go passed the infinity marker that don't have ED glass.

Do any exist? I honestly don't know off the top of my head.

ED glass has a higher expansion coefficient than non-ED glass,thus changes shape more as the temperature rises and shifts focus.

the 14 f/2.8 is an example of a AF-D lens with ED and w/o an infinity stop.

That doesn't explain AF-S lenses that go passed the infinity marker that don't have ED glass.

PB PM said:
Every AF-S lens I've ever used allows some space beyond infinity. This happens because infinity focusing distances is supposedly effected by temperature.

Every ED glass lens, not AF-S.

Your camera does not seem to fall under the list of cameras Nikon has listed as having problems with the 18-200mm VRI. To be honest I'm not sure what is wrong with the focus in the picture you posted, it looks fine, even in the larger version on flickr.

Every AF-S lens I've ever used allows some space beyond infinity. This happens because infinity focusing distances is supposedly effected by temperature.

Here is an instance when this happened...there was plenty of features that the auto focus should have worked just fine.

Has anyone had problems with their 18-200 not being able to autofocus? I was looking on the net and here http://support.nikonusa.com/app/answers/detail/a_id/13924
Seems to match my problem pretty well. I realize backgrounds need to have contrast and stuff, but in many cases if I bump the af ring manually it will move slightly past infinity and then it will lock. It has happened in cases through the zoom range, but if I can recall it only happens when the picture should be focusing at infinity. When I get home I can post an example of when it wouldn't lock and there was plenty of lines and contrast for it to. It is just this lens. I have tried other Nikons, Sigma and Tamron lenses and they all focus and locked flawlessly, but just my 18-200 has this problem. Is it possible is the problem the af ring moves slightly pass the infinity mark? Maybe because it doesn't stop on infinity the focus needs to be adjusted.

Anyway I know some on here have lots more experience and I wanted some opinions before I sent it in or anything.