Nikkor 18-200 VRII autofocus issue

[tcdev]

I've had my gear for about 4 weeks now and as I become more familiar with it, and a little more practised in the using it, I think I've found a problem with the above-mentioned lens on my D90. :(

I first noticed a problem with AF a few days ago, and today my colleague - a D40 & D90 owner - confirmed and characterised the problem further. Furthermore, he says his 18-200 VR (I) doesn't (mis)behave like this!

To re-create the problem, we zoom out to 200mm and focus on an object 20-30m away. Then we turn the manual focus ring so that it is (maximally) out of focus, and then half-press the shutter button to engage AF. Trouble is, it generally won't re-focus at all, and simply beeps as if it is in-focus. If you press the shutter button again a couple of more times, it will eventually "get the hint" and manage to focus correctly.

The camera is to set P mode, AF-Auto and we've tried both single-point and area focus. The lighting is a bright sunny day, and the frame has plenty of contrast.

We tried to repeat indoors (obviously at closer distances) but could not reproduce the problem nearly as readily; only managed to when all the contrast was towards the left of frame rather than in the middle. I also tried again at home tonight, but couldn't reproduce the problem.

My question is this - is this "expected" behaviour? Should I expect the autofocus to simply "give up" at times when it is horribly out of focus? My instinct tells me there is something wrong here...

I should also add that initially I was having problems focusing on a very high contrast sign some 50m away. If the focus just happened to be close, but not perfect, then the AF wouldn't engage at all. But re-framing on something about half the distance, focusing, then re-framing on the sign would bring it into perfect focus.

I've given the store a heads-up but they say they have to send it away for testing to their technicians, which I'm loathe to do because (a) I won't be on hand to explain the issue and (b) I bought the camera for an OS trip in 4 weeks. Also, it's a gray import which means I don't have an Australian Nikon warranty... :(

[ricktas]

Sounds like a cpu connection issue maybe. Take lens of and give the cpu contacts both on the lens and the body an inspection and possible a wipe with a soft cloth (microfibre).

[I @ M]

Couple of points to think about.

Did you do the identical test with your mates D90?
Did you swap bodies / lenses to replicate the problem on each others gear?

My (non expert) thoughts are that the contrast detect AF system expects to have some contrast to start working with. A radically out of focus target may not provide any or enough contrast to start the system working. As I understand it, along with the VR2 update and the much maligned zoom creep modification, Nikon also worked on the lens to get rid of "hunting" in the focus system.
I think they figured that having a lens and camera body that needed a clear indication of somewhere to start focussing was better than a combination that just kept on zipping in and out searching for the focus point.

I am not totally familiar with the D90 settings but I would be sitting down with your mate and comparing the various menu choices to see if something on your camera isn't set to something odd.
Another thing to try with any Nikon camera and AFS lens combination is to clean the electrical contacts on both the lens and the body with a microfibre cloth. The cleaning seems to help a lot especially with new lenses and cameras, I think they may use some sort of protective coating on new gear that prevents contact a little bit until the gear is "worn in".

[Wayne]

If you have a second D90 or other Nikon body, I would use the lens on that other body and try to replicate the problem, this will identify if the lens or your D90 is the issue.

[tcdev]

Did you do the identical test with your mates D90?
Did you swap bodies / lenses to replicate the problem on each others gear?
He is bringing his gear in today so we can try exactly that!


A radically out of focus target may not provide any or enough contrast to start the system working. As I understand it, along with the VR2 update and the much maligned zoom creep modification, Nikon also worked on the lens to get rid of "hunting" in the focus system.
What you hypothesize does make some sense. I guess I would be a lot happier if I had some official confirmation from Nikon that it was normal behaviour for the VRII. Or even confirmation from another VRII user would go some way to putting my mind at ease.

Any other VRII users able to do this experiment for me?


The cleaning seems to help a lot especially with new lenses and cameras, I think they may use some sort of protective coating on new gear that prevents contact a little bit until the gear is "worn in".
Interesting that you mention that. A few days ago, my mate saw the dreaded "F---" issue when he picked up my camera. We played with the connection, re-attached the lens, and haven't seen it since, despite trying my best to (gently) misalign the connectors.

My instinct was telling me that a brand new body/lens combo shouldn't have a contact problem, but if I read you right, you're saying that it is not uncommon for these issues with new equipment - right?!?

Thanks to all that responded to this thread! I'll give your suggestions a workout before I return the camera for testing/repair. :th3:

[I @ M]

The terminal contact problem is not rare and can show itself (the dreaded F issue) seemingly any time.
I have had it happen with various lenses and a couple of times was when they were pretty well straight out of the box. I have also seen it show up on lenses that are attached to the camera after sitting in their case for some time.

Several causes of the problem to me,

new lenses have a protective coating that needs a quick polish and old lenses develop a slight coating due to electrical conductivity and then very very slight surface corrosion from sitting around without any protective coating.
The actual contacts are by their very nature required to be a fairly low pressure connection between camera and lens as opposed to a very tight push on pull off type connection that you would find for instance in a car or computer wiring loom. Most people will know what happens when a battery terminal in a car is loose, arcing occurs at the loose points and a greasy grey coating develops and eventually the terminal refuses to let electricity through. That is an over simplified way of looking at it and rather a dramatic example but it is similar to the way the "loose" contact in the camera works.

Regular gentle cleaning of your camera's and lens's terminals with a microfibre cloth is probably something that should be done as part of general maintenance. I forget as well and mostly only do it when one particularly sensitive Sigma lens we have starts having a focus hissy fit. :D

Do a quick google maybe and see if anybody else on the www is having similar problems.
I haven't seen your problem being howled about by anybody else so I am hoping a simple clean will help you out.

[maccaroneski]

Interesting that you mention that. A few days ago, my mate saw the dreaded "F---" issue when he picked up my camera. We played with the connection, re-attached the lens, and haven't seen it since, despite trying my best to (gently) misalign the connectors.

My instinct was telling me that a brand new body/lens combo shouldn't have a contact problem, but if I read you right, you're saying that it is not uncommon for these issues with new equipment - right?!?
:

I had the F-- issue with my Tamron 17-55 and D90 - my research indicated that it is probably a D90 issue rather than a lens issue, as it occurs across a variety of lenses, including the original kit 18-105. The best resolution I could find was to wait and see what happens after the lens has been mounted and dismounted a couple of dozen times after normal usage, and my experience was that it seemed to go away after this sort of time frame.

[fillum]

Coincidentally I thought I was having a similar problem yesterday with my "series I" 18-200 (on D300). The object I was focusing on was moving a bit but when I re-pressed the shutter halfway the lens didn't seem to refocus. However given the settings and distance to subject (f/5.6, lens @200mm, subject at 40-50m) the movement may have still been within the focused depth-of-field so the behaviour was probably correct. I haven't processed the images yet but they (embedded jpegs) look ok. I just did a few tests at short range in the back yard and couldn't create any behaviour similar to yours.

If the test camera has an AF-ON button try using that to test - there could possibly be an issue with your shutter button, although given that you are getting the in-focus beep I doubt this would be the cause.

I wonder if, as you say, that the background is so blurred that the AF doesn't know where to start? Perhaps it has something to do with the focus being at the end of its range? Maybe retry the tests by moving the lens obviously out of focus but not all the way and still with enough detail for the AF to work with - not sure how much this really helps though. I know that in the past I haven't been able to get focus on things that I thought would have had plenty of contrast (but can't remember camera / lens combinations).

I guess it comes down to how the lens performs in actual shooting situations. Maybe try some more 'realistic' tests (shooting moving traffic for example).





Cheers.

[tcdev]

Coincidentally I thought I was having a similar problem yesterday with my "series I" 18-200 (on D300). The object I was focusing on was moving a bit but when I re-pressed the shutter halfway the lens didn't seem to refocus.
This was the "problem" I was seeing/imagining on Saturday when I was trying to photograph the sign across the road (except it wasn't moving, I had initially focused on something else at almost the same distance). I'm still not 100% convinced that there isn't a problem with my lens in this case, but I'd be very happy to be shown/proven wrong. :confused013

In any case, I will do some more experimenting until I've satisfied myself either way.

As for the completely out of focus scenario - my colleague was playing with his D90/18-200 VR (I) this morning in an attempt to re-create the "problem" and managed to succeed without too much trying. I guess it confirms that the contrast in such extreme circumstances is insufficient. I'm happy to accept that and move on. :food04:

I guess these issues together with the unexpected "F---" error the other day has made me paranoid that something is wrong... :o

[fillum]

...my colleague was playing with his D90/18-200 VR (I) this morning in an attempt to re-create the "problem" and managed to succeed without too much trying...I wonder whether the AF firmware 'knows' that you made a manual adjustment and consequently doesn't refocus immediately? That would be pretty clever I think. The main thing to ensure is that when you focus on things at different distances (without manual override) that the lens jumps into focus straight away without multiple hits of the shutter button.


Cheers.

[arthurking83]

First thing I thought was what fillum referred too with the manual override feature.

The M/A setting on the focus switch is apparently a manual focus priority over ride switch as opposed to a purely Auto mode with manual over ride ability.

From the lens specs on Nikon's site:


* Two focus modes available — M/A (manual-priority autofocus) and M (manual focus)

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my assumption would be that once you reset the focus distance, the CPU in the lens knows this, and probably doesn't try to refocus automatically.
While it may seem like a bad thing to you now, it is in fact a good thing, where you have better control over focusing.

I'm going to assume that the way in which to over ride the manual priority behaviour is to half press the release, let go, and do it again. I would assume that the half press you attempt the second time around would release the lens from the previously 'held' position, as it would now assume that you want to focus on something else/entirely different.

AFAIK, the VRI version of this lens doesn't have that feature, and not many of Nikon's lenses do, it's a new feature.

of course I have no experience with this lens, so I'm only assuming, and there's another test to try out.
Just be sure to have something very contrasty to focus on, like a door knob or corner of a picture frame or whatever, but it has to be prominent, so as to eliminate the problem that Andrew(I@M) described.

[aurora]

I had the same problem with my new D90 bought 2 weeks before going overseas. The camera would freeze and would not focus. I tried all settings and it wouldn't shot. It would then shot after turning on and off, taking battery out etc. It started when o/s so couldn't find out the problem till returned. The guys at the shop said the f-- code is a lens contact problem and cleaned the contacts for me, they then took over 400 shots without the message. I haven't had a chance to see if it sorted the problem. But it looks ik now.

[ozphotos]

I agonised for weeks over buying a grey market Nikon 70-200/2.8 VR II lens or getting one with a full Nikon Australia warranty. Since this lens has had a controversial start, I am going to use it for many years and the price diffence was 10% I chose the latter.

Looking at the problems people seem to be having I feel it was the right decision.

[hank]

I have had similar problems but not worked out what the issues were exactly and now I have great information to work with...Thanks heaps