Not just Nikon

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zoom nikkor 20-35 f2.8 af-DWanna do it Right....then Do it yerself .

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Posted by novicius: Mon Jul 9th, 2018 18:55

1^st Post

My 20-35 has been with me for over Nine years..traveled with me to many places , Lovely Lens...exept it could not focus past Thirty meters..yet, reviews mentioned that it is a Fantastic Landscape lens, but can not focus close ?!

Mine behaved just the opposite , Great at Close-focus , terrible past 30 mtrs., How..??

Did try the AF fine tune which could Not handle the problem.

As I have other lenses in that Focal range ( 20 f2.8 ..PC-E 24 f3.5..PC 28 f3.5...PC 35 f2.8..zoom 28-45 f4.5..all Nikon ) , I did not do anything about it.

And yet , it is not the same , for it is much quicker to zoom than to change lenses , and takes less place , which is important when traveling.

During my Long Haul in Far-East where I had the absolute minimum in lenses ( 20 f2.8..PC 28 f3.5..55 f1.2..TC 201 ..Bessa L with Heliar 15 f4.5 ) made me long for that 20-35 f2.8.

So upon my return ,I called Nikon in Danmark , to have that 20-35 fixed ,only to be told that there are No Spare parts available No longer , as the lens is too old.

So I opened it up...now, I would Never fiddle with an Electronic Marvel that modern lenses are , but what could I loose , it could not do the job as it was..so with my heart throbbing in my throat I rolled up my sleeves and went to work.

I loosened two screws that held the contacts, then unscrewed the black insert , and then the flange, removed the Aperture rings and...

That`s when I saw Three shims , removed Two of them , put it all together and....Lo & behold , Flawlessly ,It Focuses to Infinity !!

Suffice to say I am a Happy camper .

Has Anyone of You experienced / heard of something like this ??

____________________
Back in Danmark

I do not use my equipment to make photo`s .. I take photo`s to use my equipment

The better I become at photography,the better my camera gets.

Posted by Robert: Tue Jul 10th, 2018 04:57

2^nd Post

novicius wrote:
Suffice to say I am a Happy camper .

Has Anyone of You experienced / heard of something like this ??
Thanks for posting your experience novicius, and well done with your solution.

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.

Erik Lund, a good friend of mine from Copenhagen is a professional lens repair man in whom I have absolute confidence. He has great experience with older Nikkor lenses and exotics, I am certain be able to service your lens. Perhaps you might consider sending the lens to him for servicing. I very much doubt parts would be needed. If you are interested, I will contact him on your behalf. I just feel the two excess shims may not be the answer, please be sure to keep the shims safe, you may need them in the future.

As for repairing or servicing lenses, I have dabbled, but bad past experiences put me off! My fathers Zeiss Contaflex fell on the floor from a coat hook on the back of his office door, in it's case, the entire lens mount ripped from the body, I managed to re-attach the mount but was unable to re-connect the helix for some reason I still don't understand, I spent hours trying to get it re-conneted but it just wouldn't go back on. The Contaflex had a base lens with interchangeable front sections with alternative focal lengths, 35, 50 and 85mm. It was a very nice camera, a pleasure to use, he made many slides of plants and trees at Kew Gardens, which I am in the process of digitising.

http://www.adamcostelloportfolio.com/mplsDesigner/mplsDesignerBackUp_2-28-08/cameras/cameras/contaflex.html

I read Richard Haw's repair and service write up's when they appear. Richard is a watch repair man and very keen to make sympathetic repairs and servicing of older Nikon cameras and lenses.

https://richardhaw.com/lens-repair-articles/

I find them a good way of improving my understanding of the internals of older Nikkor lenses and cameras.

____________________
Robert.

Posted by novicius: Tue Jul 10th, 2018 07:59

3^rd Post

-: 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:

____________________
Back in Danmark

I do not use my equipment to make photo`s .. I take photo`s to use my equipment

The better I become at photography,the better my camera gets.

Posted by jk: Tue Jul 10th, 2018 14:30

4^th Post

Never heard or used the 20-35mm from Nikon.
Shame it was misbehaving but you seem to have corrected this.
Well done. I hope this lens gives you many great pictures in the future.

____________________
Still learning after all these years!
https://nikondslr.uk/gallery_view.php?user=2&folderid=none

Posted by novicius: Tue Jul 10th, 2018 16:32

5^th Post

jk wrote:
Never heard or used the 20-35mm from Nikon.
Shame it was misbehaving but you seem to have corrected this.
Well done. I hope this lens gives you many great pictures in the future.
Thank You J K...the near future will show and tell.

____________________
Back in Danmark

I do not use my equipment to make photo`s .. I take photo`s to use my equipment

The better I become at photography,the better my camera gets.

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