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Photography Question 

Tony Peckman 		 

Problem with Canon AF 28-105mm lens.


I have a Canon 28-105mm f/3.5-4.5 lens on my Digital Rebel. It used to work fine but now at the extended zoom range (approx. 90-105mm) it hunts wildly and won't focus on still subject at all. Even in manual focus, for some reason it acts like AF at that range, it will try to focus and messes it up.
Has anyone had that problem? In the roughly 28-90mm range it works fine.


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October 23, 2004

 

Jon Close 		  I own that lens and have never had that kind of problem.

>>"Even in manual focus, for some reason it acts like AF at that range, it will try to focus and messes it up."<<

???
If you have switched the MF/AF switch to MF and the lens still attempts to autofocus, then that switch and/or some other electronics in the lens are broken.

Otherwise the lens can hunt focus if (a) you are trying to focus closer than its minimum focus distance - probably not your situation since it has the same minimum focus distance for all focal lengths;
(b) if light levels are too low for the camera's af sensors to function reliably - this could be your situation since the maximum aperture at 90-105 is smaller than at shorter zoom settings;
(c) if there is not enough contrast in the subject for the camera to confirm focus.


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October 25, 2004

 
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