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Archive 2010What is this?
p.1 #1What is this?
What exactly is this, how is it caused, and what's the cure? Anyone know?
I have 2 or 3 lenses like this. I think it's separation of doublets (maybe a quadruplet in this particular case) where the glue dries out but I really have no idea. Sometimes like in this case, it appears to be on the outside surface but that might be an optical illusion.
If it is separation what is the proper method to separate them completely and readhere them back together? What kind of glue is used and is it necessary even to reapply any?
Any thoughts, comments, ideas?
http://tesselator.gpmod.com/Images/Temporary/_1020412.jpg
I have 2 or 3 lenses like this. I think it's separation of doublets (maybe a quadruplet in this particular case) where the glue dries out but I really have no idea. Sometimes like in this case, it appears to be on the outside surface but that might be an optical illusion.
If it is separation what is the proper method to separate them completely and readhere them back together? What kind of glue is used and is it necessary even to reapply any?
Any thoughts, comments, ideas?
http://tesselator.gpmod.com/Images/Temporary/_1020412.jpg
Sep 28, 2010 at 05:53 PM
p.1 #2What is this?
It looks like separation. I have no idea how to fix it, except to look for a place that repairs lenses. I just googled "repair separated lens elements" and got 29k hits. I'll leave it to you to read through them. 
Sep 28, 2010 at 07:27 PM
p.1 #3What is this?
I know a Zuiko 42/1.2 suffering from separation looking pretty much like that can be fixed by some time of baking inside an oven.
If the lens is of little value it might be worth a try? Don't turn up the heat too much, IIRC 75-100 degrees C was right (I'll see if I can find the directions again)... and if it fails I have no idea where from you got the idea.
If the lens is of little value it might be worth a try? Don't turn up the heat too much, IIRC 75-100 degrees C was right (I'll see if I can find the directions again)... and if it fails I have no idea where from you got the idea.
Sep 28, 2010 at 07:41 PM
p.1 #4What is this?
Hmmm that's an interesting idea
An oven huh? 100c is damn hot tho. 75c water will is too hot to put one's hand in - even if they're a professional kitchen worker and used to hot water.
Definitely sounds like something to look into tho! Thanks! And the directions if you can find them would be greatly appreciated! I'll look as well.
An oven huh? 100c is damn hot tho. 75c water will is too hot to put one's hand in - even if they're a professional kitchen worker and used to hot water.
Definitely sounds like something to look into tho! Thanks! And the directions if you can find them would be greatly appreciated! I'll look as well.
Sep 28, 2010 at 09:08 PM
p.1 #5What is this?
I found one source, here. The recommended temperature in this case was actually higher than I remembered.
Yes, I guessed you would like the idea...
Cheers, and good luck,
/Jonas
Yes, I guessed you would like the idea...
Cheers, and good luck,
/Jonas
Sep 28, 2010 at 09:46 PM
p.1 #6What is this?
Jonas B wrote:
I know a Zuiko 42/1.2 suffering from separation looking pretty much like that can be fixed by some time of baking inside an oven.
If the lens is of little value it might be worth a try? Don't turn up the heat too much, IIRC 75-100 degrees C was right (I'll see if I can find the directions again)... and if it fails I have no idea where from you got the idea.
Yikes!
OK. They may, possibly, have worked for someone at some time. Heat will melt Canada balsam, and if the elements nestle together just right, they may possibly recement. Maybe.
But the whole concept is extremely dangerous, and is far more likely to fail than to succeed:
.... rapid temperature changes (even just a dunk into hot water), can crack certain glasses
.... it's completely out for modern plastic based cements (anything in the last 30 years or so)
.... it ignores the differing thermal of expansion of dissimilar glasses, potentially leaving stress in groups that do manage to recement (between the resolidification point of the cement and the operating temperature of the lens)
.... it has limited ability to restore the clarity of Canada balsam that has grown chalky/translucent
.... it makes no provision for optically centring (or combating drift of) the elements
.... at best, it's a temporary fix. possibly very temporary
I know a Zuiko 42/1.2 suffering from separation looking pretty much like that can be fixed by some time of baking inside an oven.
If the lens is of little value it might be worth a try? Don't turn up the heat too much, IIRC 75-100 degrees C was right (I'll see if I can find the directions again)... and if it fails I have no idea where from you got the idea.
Yikes!
OK. They may, possibly, have worked for someone at some time. Heat will melt Canada balsam, and if the elements nestle together just right, they may possibly recement. Maybe.
But the whole concept is extremely dangerous, and is far more likely to fail than to succeed:
.... rapid temperature changes (even just a dunk into hot water), can crack certain glasses
.... it's completely out for modern plastic based cements (anything in the last 30 years or so)
.... it ignores the differing thermal of expansion of dissimilar glasses, potentially leaving stress in groups that do manage to recement (between the resolidification point of the cement and the operating temperature of the lens)
.... it has limited ability to restore the clarity of Canada balsam that has grown chalky/translucent
.... it makes no provision for optically centring (or combating drift of) the elements
.... at best, it's a temporary fix. possibly very temporary
Sep 28, 2010 at 10:16 PM
p.1 #7What is this?
looks like old canadian balsam,
do they still use that stuff these days?
do they still use that stuff these days?
Sep 28, 2010 at 10:22 PM
p.1 #8What is this?
OK, I'm doing it! 
Actually the idea needs modifying it a bit.
I'll place the quadruplet in a plastic bag made for boiling foods.
I'll fill the deepest pot I have with luke warm water.
I'll suspend the lens 1cm off the bottom of the pot.
The idea is that the even pressure of the water will act to press the lens together on all sides evenly, and not heat unevenly and crack.
Unless someone knows another way or has a better idea?
Actually the idea needs modifying it a bit.
I'll place the quadruplet in a plastic bag made for boiling foods.
I'll fill the deepest pot I have with luke warm water.
I'll suspend the lens 1cm off the bottom of the pot.
The idea is that the even pressure of the water will act to press the lens together on all sides evenly, and not heat unevenly and crack.
Unless someone knows another way or has a better idea?
Sep 28, 2010 at 10:29 PM
p.1 #9What is this?
brucemuir wrote:
looks like old canadian balsam,
do they still use that stuff these days?
According this this page http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/6070nikkor/telephoto/135mm.htm my lens (730xxx) is like 1959. It's a "Nippon Kogaku Nikkor-Q Auto 1:3.5 f=13.5cm".
looks like old canadian balsam,
do they still use that stuff these days?
According this this page http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/6070nikkor/telephoto/135mm.htm my lens (730xxx) is like 1959. It's a "Nippon Kogaku Nikkor-Q Auto 1:3.5 f=13.5cm".
Sep 28, 2010 at 10:40 PM
p.1 #10What is this?
Bifurcator wrote:
OK, I'm doing it!
Actually the idea needs modifying it a bit.
I'll place the quadruplet in a plastic bag made for boiling foods.
I'll fill the deepest pot I have with luke warm water.
I'll suspend the lens 1cm off the bottom of the pot.
The idea is that the even pressure of the water will act to press the lens together on all sides evenly, and not heat unevenly and crack.
At some point the cement will soften and all the elements will slip every which way against each other. This is a pretty good technique for quickly separating elements, however. (The other is an extended solvent soak.) Use a graphite pencil to draw several lines across the edges of the group before separating it.
An acetone soak will clean up the old cement. Use up lots and lots of lens tissue to remove any streaks.
Bifurcator wrote:
Unless someone knows another way or has a better idea?
You can probably still find optical grade Canada balsam, but a modern UV cured polymer cement is easier to deal with. You can get an approximate alignment (at least some alignment) by supporting the edges of the elements against machinist's "set-up blocks" on a small granite "surface plate".
Basically, you add a drop of cement, swizzle to remove any bubbles, approximate the edges, and if everything looks good you hit it with the UV. Gravity holds the cement layer to a uniform thickness. A few minutes under a strong UV LED flashlight will probably do.
Edited on Sep 28, 2010 at 10:44 PM · View previous versions
OK, I'm doing it!
Actually the idea needs modifying it a bit.
I'll place the quadruplet in a plastic bag made for boiling foods.
I'll fill the deepest pot I have with luke warm water.
I'll suspend the lens 1cm off the bottom of the pot.
The idea is that the even pressure of the water will act to press the lens together on all sides evenly, and not heat unevenly and crack.
At some point the cement will soften and all the elements will slip every which way against each other. This is a pretty good technique for quickly separating elements, however. (The other is an extended solvent soak.) Use a graphite pencil to draw several lines across the edges of the group before separating it.
An acetone soak will clean up the old cement. Use up lots and lots of lens tissue to remove any streaks.
Bifurcator wrote:
Unless someone knows another way or has a better idea?
You can probably still find optical grade Canada balsam, but a modern UV cured polymer cement is easier to deal with. You can get an approximate alignment (at least some alignment) by supporting the edges of the elements against machinist's "set-up blocks" on a small granite "surface plate".
Basically, you add a drop of cement, swizzle to remove any bubbles, approximate the edges, and if everything looks good you hit it with the UV. Gravity holds the cement layer to a uniform thickness. A few minutes under a strong UV LED flashlight will probably do.
Edited on Sep 28, 2010 at 10:44 PM · View previous versions
Sep 28, 2010 at 10:40 PM
p.1 #11What is this?
Hmmm... OK.
Thanks for that!
This is going to be fun!
The lens isn't worth a lot of money but I figure that if it's made it this far then it deserves the attention.
I guess it's worth about $150 (max) if it's good condition. I have no idea tho. I haven spent any time looking it up. I got it as is for $5. It takes great pics as long as there's no strong cross lighting to illuminate the balsam.
Thanks for that!
This is going to be fun!
The lens isn't worth a lot of money but I figure that if it's made it this far then it deserves the attention.
I guess it's worth about $150 (max) if it's good condition. I have no idea tho. I haven spent any time looking it up. I got it as is for $5. It takes great pics as long as there's no strong cross lighting to illuminate the balsam.
Sep 28, 2010 at 10:43 PM
p.1 #12What is this?
You can see that straight on it's almost transparent as it is. And on a micro four thirds body most (or all) of the flare or blur that it would cause in the image circle will miss the 4/3 sensor. It seems to anyway.
http://tesselator.gpmod.com/Images/Temporary/_1020417.jpg
http://tesselator.gpmod.com/Images/Temporary/_1020417.jpg
Sep 28, 2010 at 10:58 PM
p.1 #13What is this?
Update, I tried the boiling water trick first as to separate the elements I'm going to need to do that anyway. I kept the water at 90c for 2.5hrs. And it's didn't heal the white looking sap. It did however repair the second joint in the stack. Notice in the top pic how there seems to be something that looks like gold glitter all around the joint just under the lip of element #2... Well, that's now a perfectly shiny solid black seam.
Didn't do squat for the white band between element #1 and #2 tho. :P
Here's what the the baggy looked like. I knew my pot smoking baggy sucking high school days would pay off sooner or later.
http://tesselator.gpmod.com/Images/Temporary/_1020634.jpg
Didn't do squat for the white band between element #1 and #2 tho. :P
Here's what the the baggy looked like. I knew my pot smoking baggy sucking high school days would pay off sooner or later.
http://tesselator.gpmod.com/Images/Temporary/_1020634.jpg
Sep 29, 2010 at 06:52 AM
p.1 #14What is this?
olyacme wrote:
Yikes!
(...)
Some of the concerns you mention were mentioned in the link I gave. All of those concerns are however valid. I also wonder what can happen with grease in a lens doing this.
But... a cheap old lens and an owner willing to do an experiment. It was mu duty and nothing less to mention the method.
/Jonas
Edited on Sep 29, 2010 at 05:45 PM · View previous versions
Yikes!
(...)
Some of the concerns you mention were mentioned in the link I gave. All of those concerns are however valid. I also wonder what can happen with grease in a lens doing this.
But... a cheap old lens and an owner willing to do an experiment. It was mu duty and nothing less to mention the method.
/Jonas
Edited on Sep 29, 2010 at 05:45 PM · View previous versions
Sep 29, 2010 at 05:40 PM
p.1 #15What is this?
Bifurcator wrote:
You can see that straight on it's almost transparent as it is. And on a micro four thirds body most (or all) of the flare or blur that it would cause in the image circle will miss the 4/3 sensor. It seems to anyway.
This I don't understand. I always thought the whole front element is involved. Isn't it more possible that the flare caused by the separation isn't severe and thus more or less "invisible" in most of the images?
/Jonas
You can see that straight on it's almost transparent as it is. And on a micro four thirds body most (or all) of the flare or blur that it would cause in the image circle will miss the 4/3 sensor. It seems to anyway.
This I don't understand. I always thought the whole front element is involved. Isn't it more possible that the flare caused by the separation isn't severe and thus more or less "invisible" in most of the images?
/Jonas
Sep 29, 2010 at 05:44 PM
p.1 #16What is this?
Bifurcator! We are having fun now!
Iirc, and I do recall correctly, a critical step during re-cement is aligning the elements; nesting bowls are not so easy to align! My untested plan is to depend on gravity and un-cured cement lubrication properties by critical leveling of the bottom element -- once the bottom element is critically level, the wet cement should allow the top element dome to naturally align in the bottom element bowl. Depends on the elements however; will not work if domed element is top heavy.
Here is a link for you: http://www.optical-cement.com
Iirc, and I do recall correctly, a critical step during re-cement is aligning the elements; nesting bowls are not so easy to align! My untested plan is to depend on gravity and un-cured cement lubrication properties by critical leveling of the bottom element -- once the bottom element is critically level, the wet cement should allow the top element dome to naturally align in the bottom element bowl. Depends on the elements however; will not work if domed element is top heavy.
Here is a link for you: http://www.optical-cement.com
Sep 29, 2010 at 08:22 PM
p.1 #17What is this?
Thanks melanopsin, Kewl info.
Jonas, I think it has to do with the fact that some of the glue is still adhered to the glass surface. Where it is not it creates an edge. I suppose it would look like a cliff if you were microscopic. This edge or cliff face catches light. So when the light is more direct to the general axis of that edge (face on to the edge wall) via cross lighting it lights up and becomes VERY noticeable both to the eye and in recorded images.
That's my guess anyway. It could also be a number of other things too.
Jonas, I think it has to do with the fact that some of the glue is still adhered to the glass surface. Where it is not it creates an edge. I suppose it would look like a cliff if you were microscopic.
This edge or cliff face catches light. So when the light is more direct to the general axis of that edge (face on to the edge wall) via cross lighting it lights up and becomes VERY noticeable both to the eye and in recorded images.That's my guess anyway. It could also be a number of other things too.
Sep 29, 2010 at 11:59 PM
p.1 #18What is this?
Bifurcator wrote:
(...)
That's my guess anyway. It could also be a number of other things too.
Maybe that's how it works. From your description it sounds to me as a good hood would be the fix, at least when you use the lens with your GH1. But the oven sounds like more fun...
Cheers,
(...)
That's my guess anyway. It could also be a number of other things too.
Maybe that's how it works. From your description it sounds to me as a good hood would be the fix, at least when you use the lens with your GH1. But the oven sounds like more fun...
Cheers,
Sep 30, 2010 at 09:14 PM
p.1 #20What is this?
So you could think about re-cementing?
Probably one of these links of my Camera Repair Directory will help:
German website on cemmenting small lenses
MFLenses thread on recementting
French site on recementing of lenses
S.K. Grimes
For translation you could use
Google
Probably one of these links of my Camera Repair Directory will help:
German website on cemmenting small lenses
MFLenses thread on recementting
French site on recementing of lenses
S.K. Grimes
For translation you could use
Oct 05, 2010 at 02:31 AM