28-105 f/3.5-4.5: blow likely to limit in-focus range?

[kenneth_logan]

While on an international trip, I knocked my Nikkor 28-105 f/3.5-4.5 AF lens

against something while entering a room. Shortly after, I noticed that it

refused to come into focus at the long end of its range: say, trying to focus

on something beyond approx. 150 or 200 feet from the camera. As I do not

understand the mechanics of the lens well, I'm asking whether it is reasonable

to suppose that the blow caused the focus problem. I'm also wondering WHAT

might be knocked out of alignment or otherwise displaced to cause this problem.

 

These are important questions regarding resolution of the damage, so I'd

especially appreciate having feedback.

[frank_skomial]

"I'm asking whether it is reasonable to suppose that the blow caused the focus problem" - YES.

 

Resolution - send the lens to Nikon for repair, or use it in Manual focus, if it works and you can live with it.

 

"WHAT might be knocked" - whatever, perhaps something that you will not be able to fix yourself ? If you try to fix and fail - the repair cost could double or more.

[User_276104]

Is it ONLY the focusing that is being limited? The reason I ask is that possibly the Normal/Macro switch was bumped. This would limit zooming to the 50-105mm range, but the focus ring would move through its entire range. I know that's not what you descibed, but it's the only thing I can think of.

[titospna]

See if you've somehow tripped it into the Macro setting; perhaps that would prevent you from focusing into the distance.

 

Replacing the lens altogether is the cheaper / most cost effective option, IMO. Used ones can be had for not very much these days on auction sites.

[kenneth_logan]

I've studied the problem more--it is a problem both in the normal setting and in the macro setting. Attempting to focus on a water tower approx. 1/4 mile away, the lens seems not to focus from approx. 24-50 mm. and approx. 85 to 105 mm., but to focus between approx. 50 and 85 mm. at least to the extent that the in-focus green light comes on.

 

Seems there are no other problems possibly related to the accident, beyond the focus issue.

 

Since the lens was insured, the question has to do with whether or not a blow to the lens is reasonably likely to have caused the problem, or whether it was perhaps coincidental that the lens took a moderate blow and showed the focusing problem. Further insights would be greatly appreciated.

[titospna]

Well, the common issue in your last post is the blow to the lens. Whatever way you look at it, the accidental impact has affected the lens. However, I would mount another lens on your camera because there's a chance it's the body (or perhaps both?) that are malfunctioning. Won't even focus manually? Checked the diopter? You are fortunate to have the insurance. Good luck.