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03-17-2014, 01:59 AM   #1
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What is this appear on the lens glass ?

Here is the problem



and other samples with increased contrast








Is this what is called lens separation ? or balsam separation ,, it seen only around the corners of the glass toward the back of the lens
it unfortunately affect the image quality ,,, the lens is somewhat soft ,, i have another copy of this lens without this problem and it performs more superior ..

03-17-2014, 02:21 AM   #2
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QuoteOriginally posted by photoshoper Quote
Is this what is called lens separation ? or balsam separation ,, it seen only around the corners of the glass toward the back of the lens it unfortunately affect the image quality ,,, the lens is somewhat soft ,, i have another copy of this lens without this problem and it performs more superior ..
Yes am afraid - this is a balsam separation that is separating slowly two glass elements that has been glued together.
It is worth mentioning that this sort of balsam separation usually affects the photo quality ( from what I saw ) - but other kind - where you see like sort of patch of something oily and very colorful inside the glass - this would not affect the photo quality thaty much - only perhaps loose of contrast a bit with strong lit scenes. - at least this is what I observe with one of my lenses that has got this kind of separation. Also other thing is that your kind will progress quickly - where the other can stop for decades with one or two odd slashes of colorful separation inside - this is the case with my lens.
--manntax
03-17-2014, 07:30 AM   #3
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Definitely separation. What's the lens that it is affecting?

If it is older and uses natural Canada Balasm, this might actually be a fairly easy fix. If you can get the cemented lens doublet removed from the lens, you can place it on top of an incandescent light bulb to re-soften the balsam (watch it closely - if it gets too soft, the two halves can slide right apart!), then firmly press the two sides of the doublet together while it cools. If there is enough balsam remaining, you may be able to press out any air bubbles around the edges.

If this doesn't work, you an soak the doublet in Methyl Ethyl Ketone (MEK) solvent to remove the Canada Balsam and re-cement the elements, using machinist's V-Blocks to keep the elements aligned. The Surplus Shed (surplusshed.com) in the U.S. sells small vials of microscope slide balsam for a couple of dollars which I have successfully used to re-cement elements after letting it sit out for a couple of days to let some of the excess Xylene evaporate off.

If it is a newer lens and uses synthetic cement, this process is much more difficult, and if the lens is an inexpensive one, you might be better off just replacing it than trying to source the balsam, take the time to repair, etc.
03-17-2014, 09:08 AM   #4
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Its the Pentax-K 50mm 1.2


03-17-2014, 11:58 AM   #5
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QuoteOriginally posted by photoshoper Quote
Its the Pentax-K 50mm 1.2
That is enough to bring tears.

It may be worth having repaired if cosmetically good.


Steve
03-17-2014, 01:50 PM   #6
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QuoteOriginally posted by stevebrot Quote
That is enough to bring tears.

It may be worth having repaired if cosmetically good.


Steve
Everything is mint except this problem

---------- Post added 03-17-2014 at 11:12 PM ----------

Here is a comparison of the 2 lenses both K50mm 1.2 ,, one is mint that show glass separation and other cosmetically ugly and focus ring didn't work well but glass is good without separation problem ..



this is the one with separation @1.2



and that is the intact glass one but ugly outer condition



03-17-2014, 04:29 PM   #7
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Yeah, in this kind of separation the loss of contrast is most likely .. still a pretty usable lens though--manntax
03-17-2014, 04:33 PM   #8
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Getting old lenses fixed isn't that expensive.

Worth looking at getting it fixed up as f1.2's are getting rare.

03-17-2014, 05:44 PM   #9
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Well, the easiest thing to do would be to switch out the lens assemblies in the two - literally a 5 minute operation! Remove the front rings and retaining screws, pop out the cells, and switch them around. Of course, then you'd have an ugly lens with bad optics in addition to your nice one. Definitely worth trying the lightbulb trick on this one.

If it doesn't work, go ahead and take it to be repaired. This should use Balsam cement and should be easily re-cementable. If you aren't confident in doing it yourself, any competent camera repairman can do it for you for a fraction of the value of the lens.

Edit: Come to think of it, you probably don't even have to remove the entire lens assembly. The rear cell should be able to be switched quite easily with only a rubber tool and perhaps a JIS screwdriver to remove the mount.
03-18-2014, 12:53 AM   #10
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QuoteOriginally posted by dcshooter Quote
Well, the easiest thing to do would be to switch out the lens assemblies in the two - literally a 5 minute operation! Remove the front rings and retaining screws, pop out the cells, and switch them around. Of course, then you'd have an ugly lens with bad optics in addition to your nice one. Definitely worth trying the lightbulb trick on this one.

If it doesn't work, go ahead and take it to be repaired. This should use Balsam cement and should be easily re-cementable. If you aren't confident in doing it yourself, any competent camera repairman can do it for you for a fraction of the value of the lens.

Edit: Come to think of it, you probably don't even have to remove the entire lens assembly. The rear cell should be able to be switched quite easily with only a rubber tool and perhaps a JIS screwdriver to remove the mount.
This what i have thinking of
03-18-2014, 02:44 AM   #11
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QuoteOriginally posted by photoshoper Quote
Its the Pentax-K 50mm 1.2
I have seem the exact same situation on a k50/1.2.
I wasn't sure about that was fungus or seperation.
Now i know.
03-18-2014, 05:02 AM   #12
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What about Eric Hendrickson ?? for pentax service
03-18-2014, 05:22 AM   #13
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QuoteOriginally posted by photoshoper Quote
What about Eric Hendrickson ?? for pentax service
It is worth sending him an email for an estimate. I'm sure he could fix it at a reasonable price.


Eric's Homepage

Eric Hendrickson
pentax27@aol.com
188 Shoffner Rd
Sharps Chapel, TN 37866
Fax/phone 865 278-1051

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03-18-2014, 06:07 AM   #14
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I am not intending to second guess Eric's ability at all, but you would likely do better having it repaired locally.

This is a repair that requires absolutely no specialized Pentax knowledge, and given the expense of sending the lens to and from the U.S. from Egypt and the rates Eric charges, you would likely be able to have it repaired just as effectively and much more economically by a competent local repairperson. Not to mention the delay and risk of damage/loss/theft/etc. in the mail.

QuoteOriginally posted by atupdate Quote
It is worth sending him an email for an estimate. I'm sure he could fix it at a reasonable price.


Eric's Homepage

Eric Hendrickson
pentax27@aol.com
188 Shoffner Rd
Sharps Chapel, TN 37866
Fax/phone 865 278-1051

Tim
03-18-2014, 08:12 AM   #15
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QuoteOriginally posted by dcshooter Quote
I am not intending to second guess Eric's ability at all, but you would likely do better having it repaired locally.

This is a repair that requires absolutely no specialized Pentax knowledge, and given the expense of sending the lens to and from the U.S. from Egypt and the rates Eric charges, you would likely be able to have it repaired just as effectively and much more economically by a competent local repairperson. Not to mention the delay and risk of damage/loss/theft/etc. in the mail.
I'm familiar with opening pentax lenses and have the tools ,, and will try the halogen lamp but the question is which element is affected ,, its not clearly evident
or simply i have to direct the halogen light on the whole lens from back direction ?
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