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Flektogon 20/2.8 Infinity setting
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PostPosted: Wed May 14, 2008 4:42 pm    Post subject: Flektogon 20/2.8 Infinity setting Reply with quote
Hi all,

I was wondering how to change the infinity setting of thid lens ?

Do you know how to do it ?

Many thanks


PostPosted: Wed May 14, 2008 4:57 pm    Post subject: Reply with quote
If I remember as well Peterqd now it.


PostPosted: Wed May 14, 2008 5:13 pm    Post subject: Reply with quote
Attila wrote:
If I remember as well Peterqd now it.

Give me a minute - I was just looking for it! Smile

I think this big lens has a tendency to go out of infinity adjustment through gripping the focus and filter rings to unscrew it. My lens was focussing "beyond infinity" - it hit infinity at about the 4m mark on the dial. The filter ring should be firm, but I found it could be turned through about 30° with some force, and moving it altered the infinity focus point.

This is how I re-calibrated it. With the lens actually focussed on infinity (i.e. with the 4m mark on my lens roughly lined up with the index mark) I made a mark with a pencil on the filter ring in line with the infinity symbol on the scale, and another mark on the focus dial in line with the index mark. Then I turned the filter ring to line up the two pencil marks - simple.

This link shows how to dismantle and clean the lens, bit I didn't need to go that far.
http://www.flickr.com/photos/architect/sets/72157594225107955/

I hope this works for you too Flor.


PostPosted: Wed May 14, 2008 5:15 pm    Post subject: Reply with quote
Quote:
Give me a minute - I was just looking for it! Smile

Laughing Laughing


PostPosted: Wed May 14, 2008 6:25 pm    Post subject: Reply with quote
Many thanks Attila and Peter !!

Actually I plan to convert this Flek from Praktica B mount to EOS, so I will need to adjust infinity focus.

Cheers !


PostPosted: Fri Mar 27, 2009 12:20 pm    Post subject: Reply with quote
I had the same issue with my CZJ Flektogon 4/20. It reached infinity already between the 2 and 4m mark. So, I took it and the other M42 lenses [Tessar 50/2.8, Biotar 58/2 and Pentacon 135/2.8] to a trusted repairman for CLA. Received a lot of good knowledge about these lenses and in particular the Flek, which in particular according to him is good to have adjusted every few years if you want it to perform to its normal quality standard.

I got them back today, 2 weeks later. They've all been cleaned, removal of old lube and re-lubed with new as well as adjustment in the case of the Biotar and Flektogon.

They now focus as smoothly as can be wished, even in moderately cool temperatures (-2C). The weather forecast spells bad weather for the weekend but I do look forward to the first sunny day that arrives Cool


PostPosted: Fri Mar 27, 2009 1:24 pm    Post subject: Reply with quote
Great info!

Know i can adjust my PB Carl Zeiss Jena to focus infinite with my current PB adapter!


PostPosted: Fri Mar 27, 2009 1:26 pm    Post subject: Reply with quote
Flor27 wrote:

Actually I plan to convert this Flek from Praktica B mount to EOS, so I will need to adjust infinity focus.



just wondering ... converting or adapting ?


PostPosted: Fri Mar 27, 2009 5:03 pm    Post subject: Reply with quote
peterqd wrote:
This is how I re-calibrated it. With the lens actually focussed on infinity (i.e. with the 4m mark on my lens roughly lined up with the index mark) I made a mark with a pencil on the filter ring in line with the infinity symbol on the scale, and another mark on the focus dial in line with the index mark. Then I turned the filter ring to line up the two pencil marks - simple.

I have a bit more info on this since last year. The infinity adjustment on my lens went out again twice more, so the last time I decided to dismantle the lens and find out why.

The filter ring (which adjusts the infinity) is held in the correct position by friction, using a large screwed clamping ring with two notches. The notches are just visible behind the front element when the engraved front decal ring is removed. The filter ring should be held firm by this ring, but it becomes loose very easily if the filter ring is turned - rather a poor design I think, it would be better if there was some way of locking it. Tightening the clamping ring requires a lens spanner with offset flat tips - I'm saving up for one! Smile


PostPosted: Sun Apr 12, 2009 2:03 pm    Post subject: Reply with quote
I am bumping up this thread.

how much adjustment is possible? Could i modify the registration distance with 1~2mm? This is for easy nikon conversion?
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