Help: Focus Problem on 17-35 EDIF AFS Lens

[cd_k]

I have a 17-35 ED-IF AFS lens that develop a focus problem. The lens won�t auto focus to infinity from

the 28 to 35 focal lengths on my F5. When I manual focus on the F3, it is also out of line at the infinity

setting. Could you recommend a repair shop? I live in Washington DC area. Many thanks.

[ShunCheung]

Just in case you have dropped the lens or there has been some kind of impact, the lens mount could be bent or the elements are out of alignment.

 

Obviously Nikon USA in Melville (Long Island), New York can fix it (unless it is gray market) or you can try Authorized Photo Services in the Chicago area.

[Ed_Ingold]

If the lens does not "top out" the focus range at infinity, you probably have nothing to worry about. The lens will move past the infinity mark for a variety of reasons, including more effective servo control. The large number of elements and complex mechanism cause the effective focal length to vary with temperature. Also, zoom lenses do not hold focus exactly when the focal length is changed. The focal plane is constant only to a 2nd or 3rd order approximation. Constant focus is (I suspect) less an issue with AF lenses than with MF lenses, so more attention can be directed to issues of sharpness and distortion. Lens design is a series of compromises, as is life.

 

Your lens can be tested for alignment very quickly (and inexpensively) if you walk into a Nikon repair facility. Exhaustive tests take at least overnight. If the zoom/focus mechanism must be replaced, it will cost about $400 (re Nikon Authorized Service, Morton Grove, Illinois).

[cd_k]

Thank you, Shun and Edward, for your input. The lens has never been dropped or damaged.

I notice that it will focus passing the infinity mark. The lens works fine with distance scale up

to 10 ft at all focal lengths. But it clearly didn�t focus correctly beyond 10 ft on 35mm setting

in both manual and auto focus modes. I�m just wondering if anyone had similar problems.

[victor_tache]

Hello.

 

The infinity point is the closest point the lens gets to the focal plane (film or CCD or whatever). If something dropped inside and prevents the lens reaching that point. If a guide is borken - they are made of plastic so that there will be no metal on metal on the guides + if the lens drops the guides are cheap to replace if they break easily while a guide is pricey to replace.

 

If you tilt the lens and you hear stuff moving inside than this is probably the case. If not- then perhaps a guide ( the guide is a round little plastic thing - more or less 4 mm wide) is broken and the lens do not get to the proper position. Guides can break because of use - not neccesarily because the lens was dropped

 

Hope this helps.

 

Victor.