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Archive 2013 · 100 macro f2.8 L is usm intermittent focus on 7D
  
 
Yukonica
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p.1 #1 · 100 macro f2.8 L is usm intermittent focus on 7D


Recently I noticed my macro autofocus seemed to be inconsistent when set to full.
I don't use the lens for long work on a regular basis and don't recall problems before upgrading the 7D software.
Contacts are clean, focus works on macro, when focused on Full it is spot on accurate... it just hunts and doesn't always find the focus (especially if there is a big range between targets)
Has anyone else seem this problem?
Full disclosure: the lens did hit the floor once after rolling off my couch while changing out a different lens.
Thanks.



Jan 11, 2013 at 04:57 PM
Paul Mo
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p.1 #2 · 100 macro f2.8 L is usm intermittent focus on 7D


Without being able to physically compare your copy with mine, I think that is perfectly normal.

There are a few variables and you may just find it is the nature of the beast (100mm f2.8L IS).



Jan 11, 2013 at 06:17 PM
scalesusa
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p.1 #3 · 100 macro f2.8 L is usm intermittent focus on 7D


A lens that is dropped has a 90% probability of some internal damage. It will likely decenter some of the elements, and possibly crack or break the small nylon bushings that guide the focus helix.

Always send it to be checked out after dropping it, otherwise, it will finally fail just when you need it most.



Jan 12, 2013 at 01:42 AM
Yukonica
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p.1 #4 · 100 macro f2.8 L is usm intermittent focus on 7D


Thanks to both of you for your replies.
I have LensAlign data from when I purchased the unit. A day of fiddling about will verify the situation.
It may well be it has always been slow at focusing over distances or it could be hooped.
The lens is likely slated for a return trip to Canon Canada along with my 100-400 for precautionary service.
Servicing a lens from Yukon isn't quite the same as couriering it across the cityscape. Call it a commitment.



Jan 12, 2013 at 05:12 AM
skibum5
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p.1 #5 · 100 macro f2.8 L is usm intermittent focus on 7D


scalesusa wrote:
A lens that is dropped has a 90% probability of some internal damage. It will likely decenter some of the elements, and possibly crack or break the small nylon bushings that guide the focus helix.

Always send it to be checked out after dropping it, otherwise, it will finally fail just when you need it most.


I'd say 90% is rather overplaying it. It's certainly possible, but many lenses hold up remarkably well, without a hint of image damage after a drop. But it does depends, of course.

For porro prism binoculars you are sadly closer to the mark, a great many of those do not handle drops well at all!!



Jan 12, 2013 at 06:50 AM





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