View single post by novicius
 Posted: Tue Jul 10th, 2018 08:59
novicius



Joined: Mon Aug 13th, 2012
Location: Copenhagen, Denmark
Posts: 442
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-: I am aware of the focus limiting shims, it sounds like somebody has been in the lens but didn't know want they were doing. That said, they must have had access to the correct shims???

I would have thought it unlikely it would have made it out of the factory in that condition...

Usually these shims are used to adjust exact infinity focus. One possibility, although unlikely, is that a previous owner needed to make it focus closer but two shims would likely have little effect at the close end. Some cameras and lenses have shims under the lens mount to adjust the flange distance exactly, to ensure infinity focusing.

Given there were apparently extra shims in that position, I am wondering if the real fault might be a another issue, deeper in the lens which was actually causing the lack of infinity focus which the removal of the shims would correct.:-



Thank You for the quick reply Robert, and those Useful links,it is Appreciated.

Yes , I do store those shims in a safe place.( ye never know ) and Yes, they seem factory made, and are of different thicknesses ?!!

There was No tutorial found about the 20-35 , but I had seen some of other (A F) lenses , and about the shimming method.

I had suspected that the distance Focal point / Sensor was Incorrect ( being aware that moving the lens farther away results in Macro-photography) yet, I was Not sure because of the built in chip.

As You used to say that " To err is human , but to mess up things a computer is needed " , I`m sure You understand the butterfly in my tummy when I embarked ( for me ) on unchartered teritory.

As " Surgery " was just done yesterday evening,I am not even sure if the removal of those Two shims are Enough / Too many..

Some Lengthy / Gruelling Testing will be required , tho` I may have to open up the Lens again , as the Aperture is a bit " sluggish " , as I may have bent the Aperture Lever a tad during re-assembly ( it Was a Jiggly affair ), yet so far all seems to be well, at least better than before.

I did purchase the 20-35 2nd. hand and ,as I have read that there are those who are convinced that Wide-angle lenses are meant to do close-ups , unsuitable for landscapes even , I am wondering if it was " doctored " to do Macro, by an authorized repair facility , witnessing the use of what appears to be factory original shims.

So, ahead lies a Lengthy / Torturous period of Nervous break downs and buckets of Strong coffee , yet , the knowledge of having your crafty friend Erik Lund in my part of the world ,is a plaster on the wound.

So if all else fails ( shudder ),I may have to take You up on that .

Thank You Robert.


:cheersduo:

Last edited on Tue Jul 10th, 2018 09:51 by novicius



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