Focus not returning to beginning with Canon 100 f2.8L IS

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brentbristol
Posts: 62
Joined: 15.12.2011 18:23

Focus not returning to beginning with Canon 100 f2.8L IS

Post by brentbristol »

When using the Canon 100 f2.8L IS on a 7D at mid to long range distances Remote correctly commands the focus plane back to the first location. When one or both of the points is in the close macro range, Remote does not return the lens back to the first plane. In that circumstance I have to click on the arrow button that is supposed to return the focus back to the first plane prior clicking the "start shooting" button. Prior to clicking the "start shooting" button I have to manually adjust the stating position using the lens focus ring. It has no trouble going from near to far, but can't seem to correctly return from far to near. Again, this only seems to be a problem with close focusing, not mid-range to long-range focusing.
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Stas Yatsenko
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Joined: 06.05.2009 14:05
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Re: Focus not returning to beginning with Canon 100 f2.8L IS

Post by Stas Yatsenko »

This seems to be a mechanical issue. I would try the same test but with lens pointed up and then down. One more point. Does it happen with small focusing steps? We found that big steps are generally more reliable, it is worth testing too.
brentbristol
Posts: 62
Joined: 15.12.2011 18:23

Re: Focus not returning to beginning with Canon 100 f2.8L IS

Post by brentbristol »

The AF zone setting on this lens has 3 settings. Even though I turn AF off and the lens is being adjusted tethered the thing seems to work best if the closes focusing AF zone is set on the lens. It returns nearly to the beginning this way. If I leave some buffer steps at the near point it's return from far back to near is close enough to avoid further manual fussing with the focus.
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Stas Yatsenko
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Re: Focus not returning to beginning with Canon 100 f2.8L IS

Post by Stas Yatsenko »

You mean that lens has Macro/Tele/AF Off switch and it works properly in AF Off mode? You want us to add an option to add some steps after stack to compensate for mechanical drift?
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