New * Vintage* Lens - The Focus Off by a Foot. Ideas?

[johnloumiles]

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Hi Jan

 

Your so called ramblings definitely make sense;) but I do have one question; if the lens needs to be moved closer to the plane wouldn't I need to remove shims rather then add to them? Are there shims in the lens when it comes off the factory floor or are they added by people later on when calibrating the lens to their specific camera body? If there are no shims then I am in definite need of a anti-matter beam, isn't that what the Large Hadron Collider is for? I'll have to book some time with it! Haha

[doubice]

John,

 

Yes, there was a flaw in my ramblings.... The optical unit indeed has to be moved closer to the plane of focus to remedy your situation.

 

This can be achieved two ways: if there are shims in the lens already, remove some (or make one thinner). The other way will come into play if there are no shims and will involve a trip to Switzerland and an appointment with the Hadron Collider.

 

From what I recall, removing the optical cell from your lens is quite simple - just undo the retaining ring at the rear and the entire cell drops out - just like your 50mm f:1.8 lens. Again - going by memory, with the optical unit out, you will see immediately whether there are shims and if so, how many. The shims should be at the mating point between the optical unit and the focusing mount.

 

All this applies if the rangefinder image is correct at infinity, with the lens physically set to infinity. If the RF image is off at infinity, you have a more complex problem which would require 'professional' help. The above recommendation of John van Stelten is excellent - he worked on a couple of my lenses and his expertise is first class.

 

Cheers,

 

Jan

[johnloumiles]

Hi Jan

 

Well unfortunately there was only one shim in there and I think that might be part of the original unit. Either way it's not thick enough to make a difference ( i tried). I guess it's out of my hands. Jon must be really good, his turnaround time right now is two months. Here's a couple pics from the disassemble, it's a gorgeous lens on the inside and in pristine condition.

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