lens repair, modification and disassembly guide thread
/forum/topic/1159122/7

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Edgars Kalnins
Registered: Mar 09, 2007
Total Posts: 708
Country: Latvia

In the previous page I posted some samples with sonnar, here are two simple pictures with Tessar 35mm f3.5


Tessar 35mm f3.5 from Yashica T5 by lowlightlove, on Flickr


Tessar 35mm f3.5 from Yashica T5 by lowlightlove, on Flickr



ZoneV
Registered: Nov 20, 2008
Total Posts: 886
Country: Germany

For my experiments with flares I used UV filters, sometimes 5 stacked filter, but one big filter hand held in front of the lens worked better.
But I thought about removing lens coating as a better way. Furthermore this could be good for infrared and ultraviolet photography too.

I searched what people wrote about coating removal, but found most times chemical based ideas (Armour Etch and hydrofluoric acid for example). So I searched more for polishing agents, and found and bought several polishing abrasives.

For a first fast test I used this on a complete lens - for front
lens scratch repair - worked fine:



After this I disassembled a Helios 44 lens and uncoated this lens:



This works fine, I plan to do some further improvements - for example a cheap wide-angle lens, or probably even a zoom lens (those bad ones like 28-80 or such) for more of the effect:




mMontag
Registered: Dec 15, 2008
Total Posts: 2071
Country: United States

Markus - yeah, dig-it - nice use of that lens for that image!

I have some 50+ year old lenses that are mildly single coated - I've always wondered what a non-coated lens could render - I'll have to try this though I have a few other mods to do first.

The more you "play" with it the more you'll learn how to render with such a tool.....exploiting the aberrations.....

Thanks for posting!



triplelatte
Registered: Oct 27, 2012
Total Posts: 27
Country: United States

For anyone interested in Sebboh‘s G28 conversion, I have had some Solidworks and Catia design files made based on measurements Derek kindly provided.

I have printed the rings with a 3d printer and can confirm that the measurements are correct (although I still have to drill the mounting holes on the M adapter I got, and adjust for infinity).

If anyone has access to a CNC machine or connections to have these made cheaply in aluminum, I would be happy to buy a set..

https://dl.dropboxusercontent.com/u/24112177/FRONT_RING.zip
https://dl.dropboxusercontent.com/u/24112177/REAR_RING.zip



dkerins
Registered: Sep 19, 2012
Total Posts: 56
Country: Canada

Using the specs, I got a quote from a local firm for CNC machining.

It is not cheap for a one off but goes below $100 per adapter ring with quantities of 5 each. Any one interested?

P.S. Any opinions about the cost competitiveness of this machinist?







triplelatte wrote:
If anyone has access to a CNC machine or connections to have these made cheaply in aluminum, I would be happy to buy a set..


Commonbeing
Registered: Aug 05, 2013
Total Posts: 1
Country: United Kingdom


Commonbeing says:

I am busy cleaning my Olympus OM 50mm Zuiko MC 1.4 lens, but I am struggling to open up the front set of lenses, I have taken the front set out, but the inner ring that holds the set together won't budge. It does not have any cuts for a tool and I'm beginning to think it is glued in or something.

Does anyone have any ideas as to how to unscrew it? I have tried using a ring of the same diameter with double sided tape on the edge.

Some pictures of the ring/lenshttp://www.flickr.com/photos/99880435@N06/



sebboh
Registered: Nov 02, 2009
Total Posts: 10182
Country: United States

Commonbeing wrote:

Commonbeing says:

I am busy cleaning my Olympus OM 50mm Zuiko MC 1.4 lens, but I am struggling to open up the front set of lenses, I have taken the front set out, but the inner ring that holds the set together won't budge. It does not have any cuts for a tool and I'm beginning to think it is glued in or something.

Does anyone have any ideas as to how to unscrew it? I have tried using a ring of the same diameter with double sided tape on the edge.

Some pictures of the ring/lenshttp://www.flickr.com/photos/99880435@N06/


no experience with that particular lens, but it looks like the sort of ring that a rubber ring would work well on. in my experience such rings work well even if the manufacturer used a bit of glue to secure it. unfortunately if the threads are rusty they don't seem to be much help. i have a swamped canon FL 55/1.2 that i can't seem to open either.




ZoneV
Registered: Nov 20, 2008
Total Posts: 886
Country: Germany

I think it depends on how much of the glue is between the threads of ring and housing. I have some optical assemblies I could not open, front cell of a tokina 60-300 and some of my macro teleconverter lenses. Interessting part here some others from the same brand could be opened. Not sure wheter I tried to heat them a bit to get the glue softer (dangerous cause lens could break or get delaminated).



triplelatte
Registered: Oct 27, 2012
Total Posts: 27
Country: United States

What you found was pretty much the same as what I was quoted at some local shops for the rings.

I found a Chinese CNC shop that did small orders, and have a set of 5 each on their way now. Cost was much less than what I was quoted by anyone here in the States. They should be here in a few days -- I'll check measurements and quality when they arrive..

If they are good I'll put the remainder out for sale here. Should be on the lines of $50/pair if it works out.



dkerins wrote:
Using the specs, I got a quote from a local firm for CNC machining.

It is not cheap for a one off but goes below $100 per adapter ring with quantities of 5 each. Any one interested?

P.S. Any opinions about the cost competitiveness of this machinist?




alundeb
Registered: Nov 06, 2005
Total Posts: 4243
Country: Norway

Just stumbled across this extensive list of DIY references:

http://www.4photos.de/camera-diy/index-en.html



alundeb
Registered: Nov 06, 2005
Total Posts: 4243
Country: Norway

If anybody knows how to adjust/tighten the front barrel on the C/Y 35-70 it would be much appreciated.

http://www.fredmiranda.com/forum/topic/1161928/0



triplelatte
Registered: Oct 27, 2012
Total Posts: 27
Country: United States

Good news on the aluminum rings I had made in China for the G28 conversion. The dimensions are spot on and the holes all line up properly -- I did have to thread the holes myself as they forgot to do that part of the process -- but all in all it works; everything went together nicely and I'm hitting infinity focus. I still have some slight adjustments to make on the focusing and aperture linkage, but I'm happy with where its at right now.

I have three sets of the rings remaining -- pm if interested.







sebboh
Registered: Nov 02, 2009
Total Posts: 10182
Country: United States

triplelatte wrote:
Good news on the aluminum rings I had made in China for the G28 conversion. The dimensions are spot on and the holes all line up properly -- I did have to thread the holes myself as they forgot to do that part of the process -- but all in all it works; everything went together nicely and I'm hitting infinity focus. I still have some slight adjustments to make on the focusing and aperture linkage, but I'm happy with where its at right now.

I have three sets of the rings remaining -- pm if interested.



excellent! how much did you need to adjust the infinity stop with those measurements out of curiousity? also, can you post a pic of the finished lens?




triplelatte
Registered: Oct 27, 2012
Total Posts: 27
Country: United States

I got pretty close to using up all of the available adjustment room to get it to infinity. I'll post a few more pics later on..



triplelatte
Registered: Oct 27, 2012
Total Posts: 27
Country: United States

Here are some pics of the final G28/Rokkor conversion using the rings I had made, along with a side by side comparison with the W.Rokkor 28 2.8.





























sebboh
Registered: Nov 02, 2009
Total Posts: 10182
Country: United States

triplelatte wrote:
I got pretty close to using up all of the available adjustment room to get it to infinity. I'll post a few more pics later on..


looks good! glad to hear my measurements were accurate enough, mine uses pretty much all the available adjustment to reach infinity as well. out of curiosity, did you ask if it was possible to have the pieces made of chromed brass or have them anodized?



triplelatte
Registered: Oct 27, 2012
Total Posts: 27
Country: United States

sebboh wrote:
out of curiosity, did you ask if it was possible to have the pieces made of chromed brass or have them anodized?



They would have anodized them, but there would have been a significant delay since the shop I used would have to send them to a second factory to do the anodizing. I think it would have run a couple dollar more per ring, and I recall they wanted a bigger order to do it. In the end I decided not to do anything extra until I was sure the rings were of good quality and fit properly.

I didn't ask about chrome plated brass, but I did see on their materials list that brass was an option.



LightShow
Registered: Aug 03, 2009
Total Posts: 4960
Country: Canada

This may be usable for someone.
http://www.surplusshed.com/pages/item/m2607.html

MOUNTED WOLLENSAK IRIS ASSEMBLY F/2.5 TO F/16






There are lots of lens elements and groups etc for tinkerers, just have to browse.
This is where I found raw Canadian balsam to cement elements.
http://www.surplusshed.com/pages/item/b1077.html
Also have liquid version for slides, don't know if its good for optics.
http://www.surplusshed.com/pages/item/m3386.html


sebboh
Registered: Nov 02, 2009
Total Posts: 10182
Country: United States

for those interested in a converted contax g 45/2, i believe that one of them is available on the auction site from the member who gave me the idea that it was possible (m-a-x).

it's smaller than my conversion and focuses closer (though it's also fuji x-mount rather than m-mount).



dkerins
Registered: Sep 19, 2012
Total Posts: 56
Country: Canada

Thanks to triplelatte for the aluminum adapter rings and sebboh for the guidance, I have brought a new FrankenZeiss to life. I used a ribbon of tin from a coke can to make the aperture control on the lens body connect to the aperture ring. Seems to work well.

I found if the back aluminum adapter ring is tightened too much against the aperture ring that the aperture ring binds. Anyone else experience that? If they are lightly tight then is it fine.

I am keen to do my G45 now but need to get the one (or is it two) aluminum rings from somewhere (someone). Anyone have a lead for me to get them?



























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