Problem with auto-focus

[gumchain]

Hello, I'm hoping you can help me. My Nikon 18-200mm VR I lens is acting up. Sometimes, when in single auto-focus mode, the lens seems to focus on the subject, but will not allow the camera to take a photo with pressing the shutter button. The only way I seem to be able to get around this is to focus, then change to manual focus, then take the photo. Or, i have my camera settings set so that in continuous focus, the camera will fire whether or not the image is in focus. However, I've been getting poor quality images now using one of these two methods with the shot being out of focus. Also, it's just very frustrating to keep pressing the shutter button and the camera refuses to take the photo.

Any thoughts? I'm curious if this is something I should get Nikon to repair or if I should just replace the lens at this point.

Oh, and this problem occurs on more than one camera body. I've had issues with both the D300 and the D70. And no other lenses have this problem.

Thanks,
Joanna

[stephenpinn]

Joanna, how close are you too the subject?

[ualymerej]

you may have been too close to your subject and the camera was not locking the focus because it can't focus that close. in AF-S mode, the camera usually defaults to not taking the picture unless it locks focus. AF-C allows the camera to take pictures even if it's not in focus.

[gumchain]

No, no, it's nothing like that. I've used this lens for the past 4ish years without this problem. I'm having problems at infinity focus, at 10 feet focus, and anywhere in between. Actually I haven't had any problems at ranges too close for the lens.

[tc95]

I posted this here too... D300 AF issue

Another suggestion is to turn off the focus from the shutter button....I always use the AE-L/AF-L button to control the focus you can find that in the menu area....

Just in case here is the steps:

Menu - Setup (the picture of the wrench) - the item is F6 - then AF-ON needs to be selected...Now your AE-L/AF-L button controls your focus and your shutter button is just for the shutter....

I have had that problem...before...and just don't like using the shutter button for the AF of the lens...try this and see if it works...if it does not you probably have an issue with the camera body...otherwise the lens would not focus...

Hope this helps out...

[gumchain]

Thanks for the reply. I'll have to see if using the AE-L/AF-L button fixes it. if it does at least it'll remove some of my frustration while i decide if i'm replacing the lens or paying for a repair. It has to be the lens because as I stated, using this lens on another camera body has the same issues. And using a different lens on the same camera body fixes my problem entirely.

[jfoureyes]

I know on my D80 the shutter will not release unless the subject is in focus using AFS mode..have you tried it in AFC mode?

[gumchain]

Yes, AFC works, but I'm just not happy with the quality of the photos and not being able to focus exactly where I want to.

[shnitz]

Maybe the contacts between the body and lens are dirty? I've had lenses act up from that. Use rubbing alcohol to clean. Maybe your lens is just messed up, and you need to send it in for repair though. Go ahead and send it in.

[Rson]

Can we have a sample with Exif intact?