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Is this lens separation?
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PostPosted: Mon Feb 23, 2015 11:51 am    Post subject: Is this lens separation? Reply with quote
what do you guys say, is this lens separation?



if so I 'may' go ahead and try recementing it, which had been described so well here in this forum, I wished someone made it a sticky:
http://forum.mflenses.com/re-cementing-doublet-elements-with-canadian-balsam-t34467.html
( better I gave it a try with a cheaper lens first though..)


PostPosted: Mon Feb 23, 2015 12:44 pm    Post subject: Reply with quote
for those who are curious about how photos taken with this lens look like see 2 samples ( I haven't used this lens much, don't have many samples to chose from, and I must say it only looks that horrible if when lighting a flashlight through the lens )





Can't fault it's performance much, have been thinking that wide open sharpness possibly 'could' be better and that it easily shows PF. Can these be accredited to the fault seen, resp. to lens separation?
and: the lens is a Voigtlaender Color Heliar f2.5/75mm, the fault is in the second to last lens group which is a cemented pair. I can't make out if the fault is on it's surface or in the cementing, but suspect that it looks typical for lens separation

Last edited by kuuan on Mon Feb 23, 2015 1:05 pm; edited 1 time in total


PostPosted: Mon Feb 23, 2015 1:02 pm    Post subject: Reply with quote
From the shape of the yellowed area, I would say it is separation. You will know when you opened the lens.


PostPosted: Mon Feb 23, 2015 1:07 pm    Post subject: Reply with quote
calvin83 wrote:
From the shape of the yellowed area, I would say it is separation. You will know when you opened the lens.


thank you Calvin.
I had opened the lens but looking at the faulty group I can't make out if the fault is on the surface or 'in the middle' of the lens, that is in the cementing


PostPosted: Mon Feb 23, 2015 1:18 pm    Post subject: Reply with quote
kuuan wrote:
calvin83 wrote:
From the shape of the yellowed area, I would say it is separation. You will know when you opened the lens.


thank you Calvin.
I had opened the lens but looking at the faulty group I can't make out if the fault is on the surface or 'in the middle' of the lens, that is in the cementing

Any more photos taken from different angles?


PostPosted: Mon Feb 23, 2015 1:32 pm    Post subject: Reply with quote
calvin83 wrote:

Any more photos taken from different angles?


looking through the lens without flashlight it looks clean. The fault only can seen when using a flashlight and for taking the photo I had to find the right angle. Even when looking at the lens group only, after removing it from the lens, one hardly can make out the fault. I may try to take other photos tomorrow, then of the group only, but I suspect that I can't take any better ones than shown.

oh, I do have more photos that I had taken today:





PostPosted: Mon Feb 23, 2015 1:42 pm    Post subject: Reply with quote
If the damage is in the surface, you should see it when you looking at the lens group alone at an angle under a light source.

Here is the same lens with fog(separation) http://lens-cla.blogspot.hk/2014/02/voigtlander-color-heliar-75mm-f25-mc.html


PostPosted: Mon Feb 23, 2015 1:56 pm    Post subject: Reply with quote
calvin83 wrote:
If the damage is in the surface, you should see it when you looking at the lens group alone at an angle under a light source.

Here is the same lens with fog(separation) http://lens-cla.blogspot.hk/2014/02/voigtlander-color-heliar-75mm-f25-mc.html


ok, I shall see again tomorrow ( won't open the lens now, being tired, at 1 AM Wink )
thank you for the link Calvin! It is the same cemented group shown in the link which is faulty in mine. I'd say that confirms the suspicion that it is lens separation. Are there any tips that you can forward, that can be taken from that blog?


PostPosted: Mon Feb 23, 2015 2:01 pm    Post subject: Reply with quote
calvin83 wrote:
...
Here is the same lens with fog(separation) http://lens-cla.blogspot.hk/2014/02/voigtlander-color-heliar-75mm-f25-mc.html


Thank you for that link! He does professional what I do for my own lenses, separation repair and lens polishing.


PostPosted: Mon Feb 23, 2015 2:27 pm    Post subject: Reply with quote
There is no tips on how to do that in that blog. You may follow the guide from Markus(ZoneV) http://www.4photos.de/camera-diy/Delamination-Separation-Repair.html or http://www.skgrimes.com/library/old-news/old-lenses-can-be-restored-by-re-cementing or http://www.largeformatphotography.info/forum/showthread.php?65756-One-way-to-fix-lens-separation . Different people use slightly different approach.


PostPosted: Mon Feb 23, 2015 2:37 pm    Post subject: Reply with quote
calvin83 wrote:
There is no tips on how to do that in that blog. You may follow the guide from Markus(ZoneV) http://www.4photos.de/camera-diy/Delamination-Separation-Repair.html or http://www.skgrimes.com/library/old-news/old-lenses-can-be-restored-by-re-cementing or http://www.largeformatphotography.info/forum/showthread.php?65756-One-way-to-fix-lens-separation . Different people use slightly different approach.


thank you so much Calvin for the links!
Actually I had seen this very same sites, they had given me confidence that I may be able to to it myself Smile
cheers, andreas


PostPosted: Mon Feb 23, 2015 2:42 pm    Post subject: Reply with quote
ZoneV wrote:
calvin83 wrote:
...
Here is the same lens with fog(separation) http://lens-cla.blogspot.hk/2014/02/voigtlander-color-heliar-75mm-f25-mc.html


Thank you for that link! He does professional what I do for my own lenses, separation repair and lens polishing.


Markus thank you very much for participating in this thread!
I had found your instructions so very helpful, they may make me try out myself!

Most interesting I found that you use 'Uhu Glas' for re-cementing. I guess that by now you must have done this, and used Uhu Glas for some other lenses too, right?

ha, you even do lens polishing! I could use a few tips about that too! There is a number of faulty Canon LTM lenses that I have, typical milky, etched glass and all my attempts of polishing them have not yielded much result. Same with my M-Rokkor 2.8/28. Do I find tips on polishing on your blog? Or can you give me hints here please, point me to where find info, or can I ask you specific questions per PM?

thank you so much, andreas


PostPosted: Mon Feb 23, 2015 3:17 pm    Post subject: Reply with quote
kuuan wrote:
calvin83 wrote:
There is no tips on how to do that in that blog. You may follow the guide from Markus(ZoneV) http://www.4photos.de/camera-diy/Delamination-Separation-Repair.html or http://www.skgrimes.com/library/old-news/old-lenses-can-be-restored-by-re-cementing or http://www.largeformatphotography.info/forum/showthread.php?65756-One-way-to-fix-lens-separation . Different people use slightly different approach.


thank you so much Calvin for the links!
Actually I had seen this very same sites, they had given me confidence that I may be able to to it myself Smile
cheers, andreas

If you can access to a lens analyzer/meter(usually found in glasses shops), you can measure the centering of the lens group after you cemented it. Here is another thread in a forum on my city on element repair showing the digital lens analyzer:
http://www.dchome.net/forum.php?mod=redirect&goto=findpost&ptid=1164990&pid=13685884&fromuid=281250


PostPosted: Mon Feb 23, 2015 8:26 pm    Post subject: Reply with quote
kuuan wrote:
...
Markus thank you very much for participating in this thread!
I had found your instructions so very helpful, they may make me try out myself!

Most interesting I found that you use 'Uhu Glas' for re-cementing. I guess that by now you must have done this, and used Uhu Glas for some other lenses too, right?

ha, you even do lens polishing! I could use a few tips about that too! There is a number of faulty Canon LTM lenses that I have, typical milky, etched glass and all my attempts of polishing them have not yielded much result. Same with my M-Rokkor 2.8/28. Do I find tips on polishing on your blog? Or can you give me hints here please, point me to where find info, or can I ask you specific questions per PM?
..


Andreas, here my lens polishing websites:
Lens antireflection coating polishing, lens scratch polishing.
I tried the Zeiss method with cigarettes ash ones, but the coating was too hard to be polished with that. Or the cigarettes are too soft Wink

I think I have repaired a second lens with the Uhu Glass, but not sure which one. The repaired Wirgin 85mm/1.9 works very well, use it often at the moment. I have a Rodagon with delamination, waiting for the repair, and I think at last another lens that could be repaired.


PostPosted: Wed Feb 25, 2015 8:50 am    Post subject: Reply with quote
ZoneV wrote:

Andreas, here my lens polishing websites:
Lens antireflection coating polishing, lens scratch polishing.
I tried the Zeiss method with cigarettes ash ones, but the coating was too hard to be polished with that. Or the cigarettes are too soft Wink

I think I have repaired a second lens with the Uhu Glass, but not sure which one. The repaired Wirgin 85mm/1.9 works very well, use it often at the moment. I have a Rodagon with delamination, waiting for the repair, and I think at last another lens that could be repaired.


thank's a lot for that Markus!
certainly I shall follow your tips and not give up trying to improve the 'milky' lenses I have.
About using Uhu Glas, I guess once glued there is no way to get the elements apart again, what do you think? Fearful that this might be necessary I shall try to get hold of some Canada Balsam instead. Anyways, no hurry for trying that repair, shall only do it once I have a good enough set up.
thank you again everybody,
cheers, andreas


PostPosted: Sun Dec 20, 2015 8:27 am    Post subject: Reply with quote
calvin83 wrote:
If the damage is in the surface, you should see it when you looking at the lens group alone at an angle under a light source.

Here is the same lens with fog(separation) http://lens-cla.blogspot.hk/2014/02/voigtlander-color-heliar-75mm-f25-mc.html


That site seems to have disappeared ( or is it just blocked here, in Vietnam? )
Calvin, do you know if there any information on that site on what kind of cementing was used, resp. how easy / difficult it was to separate the elements? I have tried, but did not have success.


PostPosted: Sun Dec 20, 2015 9:02 am    Post subject: Reply with quote
kuuan wrote:
calvin83 wrote:
If the damage is in the surface, you should see it when you looking at the lens group alone at an angle under a light source.

Here is the same lens with fog(separation) http://lens-cla.blogspot.hk/2014/02/voigtlander-color-heliar-75mm-f25-mc.html


That site seems to have disappeared ( or is it just blocked here, in Vietnam? )
Calvin, do you know if there any information on that site on what kind of cementing was used, resp. how easy / difficult it was to separate the elements? I have tried, but did not have success.

The site is working at my side. The is no information on how he separate the lens element. I have included the information on how to remove the UV-glue on the other thread:

Lloydy wrote:
calvin83 wrote:
kds315* wrote:
It might have been cemented using UV cemented, hardened by UV light.
This can't be seperated by your method.

This may help but need to be careful with the chemicals.
http://www.dymax.com/images/pdf/literature/lit079_removal_of_cured_uv_adhesives_tb.pdf


MEK, mentioned in the data sheet, is easily available from most plumbing and building merchants as it is the solvent used to clean PVC pipework before gluing. Be very careful, it is very nasty stuff. Not only to the user, it will strip paint.


PostPosted: Sun Dec 20, 2015 9:07 am    Post subject: Reply with quote
thank you very much for your fast reply Calvin, and great that you linked to the other thread, where you were so kind and linked to the info how to separate UV cementing Smile
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