D90 metering issue with 18-200mm HELP!

[richardrash]

Hi all, I just bought a used D90 and I have a very very very weird issue with it.

When I switch to Aperture priority or Shutter priority, using my 18-200mm VR II (a few months old), and I shoot a few shots at the exact same thing in similar lighting condition over a period of few seconds, I start getting differential metering. I was using area autofocus, shooting the brick fence wall of my house at 3pm in the afternoon. I was at f 3.5, and for the first shot it auto meters at 1/60 sec. After I take that shot, I noticed the viewfinder dims a little bit, and all of a suddenly it meters at 1/30 of sec. I take that shot, and then I have 1/15, and then to 1/10, then to 1/5. Then it stops pretty much at 1/5. This strange thing happened even if I go to S, and the shutter speed just keep increasing as I take more shots to compensate for more lighting.

I dont have bracketing turned on, my battery is full, I have cleaned my sensor, I have reset, I dont have multiple exposures, I dont have any sort of exposure compensation turned on, i cleaned the battery contacts, I cleaned the len contacts.

Now I thought it could be my used D90 right? So I test it with my 35mm f1.8, Sigma 10-20mm f4, Tamron 28-300mm VC, Tamron 17-50mm f2.8, Nikkor 18-105mm f3.5 and no such thing happened!!!

Now I thought it could be my 18-200mm VR II right? So I head out to a local camera store and bought the exact same lens and the same thing happens at home!

Ok so if my camera works and my len works, what the h**l is happening?

I take out my D5000 and test all the lens again. It works perfectly and no such problem exist, even for the 18-200mm

I think it over and over again, and there is 1 thing that I did yesterday which might be the issue. I updated the firmware from 1.000 to 1.002 properly shortly after I bought the used camera. But I am surprised I cant find any such problem online, especially I am sure many D90s use 18-200mm VR II and they have updated firmware? I am so very frustrated because the used camera is out of warranty obviously, but yet it seems to work with everything else.

Please please help if you heard of such an issue before. To make things worse I am heading off vacation in a week ....oh and yes I've sold or going to sell off my D5000 and most of the lens online

Thanks for your time for reading through all this

[kirbinster]

I can think of two possible issues. First there is "A" and "B" firmware, did you update just one or both. IF just one the camera can do strange things.

The other is do you have the meter set to spot or matrix. If spot you might be just metering slighly different depending what the spot is on.

If none of those two then it must be micro gremlins, they will cause problems at times

PS - I would keep the D5000 if you can manage the bucks. I have a D700 and a D300 but love my D5000 for many applications because it is so small and lightweight.

[richardrash]

Thanks for the reply...
really..there is a A and B firmware? Well I only downloaded the only one available on nikon's support website, and the camera is reading A 1.000 B 1.000 L 1.002

Yeah actually Nikon had me tested like a dozen or so scenarios, and still they cannot find the problem with it. They are asking me to send in my camera + lens..great. I am glad I still have my D5000 to take onto vacation. And who knows how much they are going to charge, maybe it's cheaper buying another camera.

They had me tested using every single mode available, Auto A S M Auto/flash off, had me tested interior lighting and exterior lighting, different metering and different focus mode etc.
The results all came out the same. Turning off Active D-lighting, Noise reduction, and have me uploaded like over 20 image samples. There is always problem with 18-200mm VR II with my D90..and there is no problem with any other lens. And it happened on both 18-200mm VR II that I have...one is 3 days old and 1 is 3 months old. I have a 18-105mm which is broken, and it still auto-focuses and shoots pictures without such a problem. Really frustrated

Yeah now i am seriously considering selling off the D90 and keeping my D5000 and wait for D7000 to drop to a sensible price range. Hopefully whoever buys it will not get a 18-200mm VR II sigh

[Almond.Butterscotch]

Before you send it in, try rubbing the electrical contacts on the lens with the pink eraser on the back of a pencil. See if that helps.

[Azaki]

The op said he was outside. Are you sure a cloud didn't float by, and cast a shadow on you. that would change the amount of light and metering value.

[richardrash]

Hmmm..I am pretty sure that didnt happen. We dont get much clouds in los angeles lol
Also a lot of test sample shots were taken indoors under fixed lighting conditions, with a center point metering on the same object...

i did rubbing the contacts with the erasers but doesnt seem to help, thanks for bringing it up

[richardrash]

Brought camera to local store and found the problem.
It's a bent diaphragm lever from lens attaching/detaching, and accidentally bending the lever.
So whenever the camera takes a shot the lever is unable to return to its original position, thus metering less and less.
Need to disassemble the entire camera and carefully bend the lever to be perfectly straight without breaking it...