Autofocus problems

[dmatsui]

This problem has occured quite recently. Basically my nikon d80 fails to focus properly with an assortment of lenses. What happens is that it hunts allot when it shouldnt and occasionally studders. Its like a rapid focus stop focus stop focus stop. If that makes any sense. I've also had the problem that the focus locks on a subject when it is quite clear that the subject is nowhere close to being in focus. So far i've noticed this problem on the 18-55 kit lens aswell as the 105mm f2.8. I've tried removing the lens and putting it back on the camera which has mixed results. Sometimes it works sometimes it doesnt.
This leads me to believe that the problem lies within the contact points in the dslr itself.

For the record my nikon d80 is about a year and a half years old as is my kit lens and my 105mm is a little less than a year old. None of the equipment has been dropped or been in situations where the gear could have malfunctioned.

should i let a shop look at it or is it as simple as cleaning the contact points? (If so how would i go about doing this?)

 

[Big Mike]

Did you accidentally adjust the focus on the viewfinder eyepiece?

 

[craig]

Try moving the focus points or changing focus modes. Sometimes if you are too close the lens will have trouble focusing.

Love & Bass

 

[Joves]

I would try cleaning the contacts first. I use QED from NAPA I spray it on a Q-Tip and then run it through the mount all the way around, I like to get any dust out of the mount as well while Im at it. Then use the dry end and, see if it comes up clean. Then you do the lens contacts.
Also as was said you may either be too close to the subject or, the subject amy not be defined enough, also are you using Continuous Focus or, Single Focus. Try changing that.

 

[toooldtowait]

I had this problem once on my D300. The auto focus kept searching. Then I noticed the little lever on the front of the camera had moved to M (manuel) from S. No problem after switching it back.

 

[dmatsui]

i'm pretty sure its not a problem to do with focus points nor with continous or single focus modes, i've tried all of those before. I'll try adjusting the viewfinder eyepiece focus but i'm 99% certain that that isnt the problem. My issue is mostly with the focus studdering.
I've also tried focusing on various different subjects but have had the same problem nomatter what they where.

 

[Garbz]

I would try cleaning the contacts first. I use QED from NAPA I spray it on a Q-Tip and then run it through the mount all the way around, I like to get any dust out of the mount as well while Im at it..

Wow that's a lot of effort. We electrical engineers just scribble on the contacts with a pencil.

No need to even rub it off afterwards, since graphite is very conductive.

 

[Moglex]

i'm pretty sure its not a problem to do with focus points nor with continous or single focus modes, i've tried all of those before. I'll try adjusting the viewfinder eyepiece focus but i'm 99% certain that that isnt the problem. My issue is mostly with the focus studdering.

Can you describe this 'studdering'? It isn't something I've ever heard of.

It does sound very much like a contact problem or a loose connection somewhere in the camera.

 

[dmatsui]

its very hard to describe the studering. Put it this way the autofocus doesnt focus smoothly. It focuses more in jumps (at times). Sometimes the camera works perfectly fine, at other times it will "studer" or simply not focus at all.

Do you think i should bring it in? Problem with that is i dont know how much it is going to cost me so if its something that can be fixed i would like to try it myself.

 

[Moglex]

its very hard to describe the studering. Put it this way the autofocus doesnt focus smoothly. It focuses more in jumps (at times). Sometimes the camera works perfectly fine, at other times it will "studer" or simply not focus at all.

Do you think i should bring it in? Problem with that is i dont know how much it is going to cost me so if its something that can be fixed i would like to try it myself.

If you've carefully cleaned the contacts and (if you know what you're doing) the inside of the camera (in case dust is interfering with an autofocus sensor) there's probably not much more you can do. If you have a good local camera shop that you trust you could ask for a repair estimate.

Somewhat OT but I'm still intrigued by this word 'studering'/'studdering' which I can't find in the dictionary. The action you describe sounds like 'juddering' ?

 

[table1349]

I had the same problem with my Canon 24-70 f2.8L. Now I realize that this is a Canon lens with internal focus, but bear with me. Not sure if you are using in body focus or in lens focus with you D80 and the lenses that you mention. Since it is happening on both lenses, I would suspect in body.

The problem for my lens turned out to be a simple problem. The motor mount ring had broken. The motor had some play in it and when operated the torque caused it to shift slightly, causing the motor to bind. This caused my lens to stutter and hunt.

A week at Canon factory service and $175.00 later it is better than new, as they replaced the broken mount ring, checked and recalibrated the lens. If you are using an in body focus motor I would suspect that something is allowing that motor to move or is jamming it in some way causing the stuttering problem.

 

[dmatsui]

its possible studdering is a dutch word i mis translated to english. My first language is english but i get confused on occasion. Actually dont i mean Stuttering?

At any rate it sounds like i'll probably have to send it in. Thanks for the help though

 

[Andrew Boyd]

Sorry, you definitely have to send this one in for repair. When it replicates the same issue with several lenses, you know the problem is with your camera body.
Andrew Boyd
TheDiscerningPhotographer.com

 

[Garbz]

Not so much repair as much as cleaning. AF works using a small CCD in the bottom of the camera body. If that gets dusty which can happen then the camera will hunt and refuse to focus properly. On the upside this is a cheap fix.