D80 with 18-200 VR focusing problem

[mrgjlg]

I want to see if anyone else has experienced this with their 18-200 VR. At the wide end of the zoom – about 18 to 35 mm, it just won’t find and lock focus most of the time. Right at about 35 it tends to lock focus, but not necessarily always – beyond that it’s ok. I’ve tried every mode, including: with and w/o VR, AF-A, AF-S, AF-C, single-spot focus or multi or dynamic – focus light on or not – it happens in both broad daylight and indoors with varying light. It usually doesn’t even attempt to hunt. If I zoom in more on the same subject, then it starts to focus OK, though it’s sometimes slow-ish to do so. It doesn’t matter what the subject is or how much detail it has – and I make sure that the focus point doesn’t cover objects at varying distances, no mirrors or confusing patterns, etc. I’ve jiggled the AF/M switches on the body and lens. In this situation, sometimes it won’t focus at all, and sometimes it finally locks after 5-15 seconds. Out at about 50+ mm it focuses much better. At 18 mm, if I stand within 6-10 feet, it starts to work – but for that same subject, if I step back some it starts to fail to focus. It’s as if it wants the subject to be “large” under the focus point. I have also tried a complete reset of the camera. It's never been dropped.

Under the same conditions and settings and scenery, if I put on my only other AF lens, a 35-135 Nikkor, it’s always focuses ok – but then again, that setting of “35” is that border line where it seems ok on the 18-200.

From this, I couldn’t be sure if it was the body or the lens and neither could the Nikon tech on the phone, though it seems like the lens. So it’s going in for repair.

 

[drip01]

I thought mine was broken but it looks like this is a slow lens that needs plenty of contrast to lock focus. My workaround is by turning the focus ring while pressing the shutter. This will force it to fire. The resulting image always seems to be in focus.

--
Brian
http://www.pbase.com/drip

 

[Terence_T]

I dont understand how would the focus be sharp when you turn the focus ring while pressing the shuttle.

 

[Petruska]

My D80 and 18-200 VR lock focus with ease and fast at any focal length and F stop. Even in dim lighting. I don't think it has ever hunted for a focus lock. How sharp are your pictures when the lens does focus? If they are on the soft side then there is a possiblity that the focus is going to be hard to lock on. Does the lens or body front or back focus? Send the lens back for repair with a good detailed letter explaining the issue.

 

[drip01]

Focus priority instead of FPS Rate priority? The latter will fire regardless of focus lock or not.

--
Brian
http://www.pbase.com/drip

 

[drip01]

I dont understand how would the focus be sharp when you turn the
focus ring while pressing the shuttle.

Lenses with Full Time Manual focus ring allow you to adjust focus manually. The shutter will fire when the focus is locked, therefore, the image will be sharp.

--
Brian
http://www.pbase.com/drip

 

[mrgjlg]

My D80 and 18-200 VR lock focus with ease and fast at any focal
length and F stop. Even in dim lighting. I don't think it has ever
hunted for a focus lock. How sharp are your pictures when the
lens does focus? If they are on the soft side then there is a

possiblity that the focus is going to be hard to lock on. Does the lens or body > front or back focus?

It tends to be sharp for most pictures when it does focus, except at 200 where it can be really soft. But at 200, it alwasy autofocuses anyway. I don't think it is front or back focusing.

I thought mine was broken but it looks like this is a slow lens
that needs plenty of contrast to lock focus.

It doesn't matter what how much contrast there is, it still fails.

Focus priority instead of FPS Rate priority? The latter will fire
regardless of focus lock or not.

I know I can make it fire without focus lock, but that's not the point. It should at least attempt to focus and sometimes it does not even do that. During the conditions I described, I can focus manually faster than anything it does attempt to do - but that defeats the purpose of having an AF lens!

There's no question that something is wrong. I've sent it in with a note.

 

[Movinon]

My d80 and 18-200 always focus just right. I don't think mine has ever had to hunt. I use mine indoors a lot. Low light and in museum no problem. Have your local camera shop check it out.
--
ED..............movinon

 

[mrgjlg]

I'm happy to report that Nikon fixed my problem. It looks like it was the body. They say the replaced the "front body" - though I don't know exactly what constitutes that part. And Nikon adjusted the "auto focus operation" on the body. On the lens (which one could have concluded was the problem initially) Nikon only reports several "checks" - but no adjustments.

The end result is night and day. It (D80 + 18-200VR) now autofocuses quickly and accurately under the same conditions I originally described (i.e. at the wide end of the lens) - whereas before it wouldn't even attempt to focus under those conditions most of the time.

 

[alpshiker]

I have a similar problem with the 18-200 VR on a Fuji S3 body. Although I didn't notice the problem when I first got it, it looks now as if AF focussing is impossible at the wide end of the lens whatever the light intensity if the focus point is at or close to infinity. I have to zoom in and press the release mid way, zoom back and trigger. Or alternatively move the manual focussing ring back ant forth. But this is of course very annoying when a quick response is needed, and aslo modifies the light metering and focus accuracy. On occasions the lens does not focus at all even at longer range and I have to switch the body off and on. Should I send the lens to Nikon? Any further experience?

There is a technical notice on the Nikon website which states that some Nikon bodies require a firmware update to properly use that lens. Maybe I should check Fuji for any remark related to this lens too.

http://support.nikontech.com/cgi-bin/nikonusa.cfg/php/enduser/std_adp.php?p_faqid=13924

 

[mrgjlg]

I thought it was the lens, but Nikon didn't seem to actually make any changes to it. It was the body that they fixed. I don't have any experience with Fuji bodies.

 

[Leonard Shepherd]

AF does not work well with small and relatively featureless AF targets - common with wide angles and distant targets.

Nikon point out in the lens instructions targets smaller than half the viewfinder mark or very lacking in detail may give AF a hard time with wide angle DX lenses.
This is an AF limitation, not a lens issue.

Find some good AF targets at close distance and AF should work fine - even at 18mm. When AF does not start it is usually because the AF target is one which AF cannot detect. Nikon suggest either focus lock on a better target or manual focus as work arounds when needed.
--
Leonard Shepherd

Whilst the camera and lens can be important the photographers skill and imagination are much more important in achieving good pictures.

 

[alpshiker]

Someone pointed to me the free Fuji adjustement call back. They adjust something on the lens mount (?) on the body so that the 18-200 should work properly. It's been discussed there:

http://forums.dpreview.com/forums/read.asp?forum=1020&message=23876423

 

[mrgjlg]

AF does not work well with small and relatively featureless AF
targets - common with wide angles and distant targets.
Nikon point out in the lens instructions targets smaller than half
the viewfinder mark or very lacking in detail may give AF a hard time
with wide angle DX lenses.
This is an AF limitation, not a lens issue.
Find some good AF targets at close distance and AF should work fine -
even at 18mm. When AF does not start it is usually because the AF
target is one which AF cannot detect. Nikon suggest either focus lock
on a better target or manual focus as work arounds when needed.
--
Leonard Shepherd
Whilst the camera and lens can be important the photographers skill
and imagination are much more important in achieving good pictures.

Once Nikon repaired the body the difference is night and day - with the same subjects. The camera and lens now focus virtually instantly where before it would not even attempt to focus. This applied to any of many, many subjects - some "small", some not - before they repaired it, there were very few subjects it could focus on under the limitations I originally described. I'm familer with the various limitations of the AF system - nothing to do with my skill.

I am perturbed that I had to pay to send it in and get it repaired under warranty. But they fixed fairly quickly and appear to have done a good job since it works so well now - and I'm greatful I got it back in time for a big trip I'm taking soon.

 

[maurice h]

I have just purchased 18-200, i use it on nikon D200, i photographed a group in a hall because of the rain, so i was wide angle to get them in and i stood as far back as possible. The camera bleeped 'in focus' but when i got the images home they were not sharp.

I have now worked out that if i zoom in to a face with the 200 end, focus, hold shutter release, zoom out, compose, and then release shutter all works fine.......that cant be right for a nikon... what is going on with nikon, im tempted to take up the canon challenge. Im going back to nikon with this one.

 

[BasilG]

AF does not work well with small and relatively featureless AF
targets - common with wide angles and distant targets.
Nikon point out in the lens instructions targets smaller than half
the viewfinder mark or very lacking in detail may give AF a hard time
with wide angle DX lenses.
This is an AF limitation, not a lens issue.
Find some good AF targets at close distance and AF should work fine -
even at 18mm. When AF does not start it is usually because the AF
target is one which AF cannot detect. Nikon suggest either focus lock
on a better target or manual focus as work arounds when needed.

Come on, it's getting repetitive... they fixed his body, so what you're saying (all the time & in every focus problem post that is posted) doesn't apply here. There are certainly cases where AF fails due to bad AF target, but there are also cases where the camera or the lens are faulty. I wonder why the latter is so difficult to accept.

BG