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05-14-2011, 08:21 AM   #1
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Lens "defect"?

I recently acquired a Zeiss zk 85/1.4 which was plagued with some kind of "white spots" below the first couple of elements. Believing it to be an isolated case of bad luck, I got a replacement copy. Surprisingly, or maybe not, the second copy shows exactly the same problem. Interestingly, the serial numbers of these two lenses are quite distant from each other, making me believe that they are probably from very different batches - meaning this could be a common "defect" for this lens?! From the lens design, there don't seem to be any gluing of the first few elements - does this eliminate the possibility of element separation? Finally, it doesn't quite affect the IQ as far as I could tell and I could probably live with it if it is indeed some lens characteristic.

I would appreciate any inputs here and specially welcome owners of this lens to do a sanity check on their lens. Thanks in advance.



05-14-2011, 08:52 AM   #2
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Pixie dust?
05-14-2011, 09:01 AM   #3
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That's pretty encouraging. <;
05-14-2011, 09:12 AM - 1 Like   #4
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Condensation?

Kim

05-14-2011, 09:15 AM   #5
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QuoteOriginally posted by Kim C Quote
Condensation?

Kim
Not exactly. I am pretty sure its not water and they do not go away.
05-14-2011, 09:37 AM - 1 Like   #6
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Let us see it?

edit: images load slow on dialup!

Could be oil fraction mist deposit from helicoid grease over heating...any on diaphragm blades?...an experienced person should be able to clean easy, key word "experienced" -- this is a valuable lens, worthy of professional restoration. Or, just use it -- any visible effect is very unlikely, even for pixel peepers!

Last edited by rhodopsin; 05-14-2011 at 09:44 AM.
05-14-2011, 09:49 AM   #7
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It isn't air bubbles in the glass is it? This isn't too uncommon.
05-14-2011, 09:55 AM   #8
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I meant originally caused by condesation. When the water evaporates it leaves the spots behind.

Kim

QuoteOriginally posted by scorpioh Quote
Not exactly. I am pretty sure its not water and they do not go away.


05-14-2011, 06:40 PM - 1 Like   #9
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My FA100/2.8 had condensation b4 but didn't look like this at all. I think it's either glass bubbles or fungus. You should be able to tell under a high magnification loupe. Perhaps you should ask this at FM because ZE/ZF are quite popular there.
05-14-2011, 07:18 PM   #10
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Thanks for all inputs so far. It's not too clear from the first picture but the spots as I could tell are on the bottom surface of the first element and the top surface of the second element. While they are randomly positioned, they spread evenly across the entire surface of the elements.

05-14-2011, 07:24 PM   #11
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I could be wrong but I cannot help but thinking that is fungus. Removing the 1st glass for cleaning might be an easy task though depends on the design. I hope I was wrong.
05-14-2011, 07:28 PM   #12
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Fungus came to my mind too but I am wondering if there are such "spot fungus"? There are no web tracks or such. On the other hand, since I got both my copies from B&H, it may be possible that all copies are infected since they are probably stored in the same place! Yes, it may not be manufacturing! Ah...
05-14-2011, 07:30 PM   #13
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If it's fungus, you might be able to tell under a high power magnifier (or use a 50mm).
05-15-2011, 03:02 AM - 1 Like   #14
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In that this is a replacement copy for the original - with the same problem, I would write to Zeiss directly and ask them if they could help out with an explanation. The lens is expensive, and with Zeiss' reputation for build, lens quality, and design - I would have to think that its not fungus and thus some sort of cleaning residue. If that is the case, then there is a whole set of questions concerning quality control of the build process and what is acceptable for the final inspection, etc.

Even if it does not currently affect the IQ, what does it do to the future resale value - rather than any appreciation, might you have to take some level of a price reduction (a letter of explanation on Zeiss letterhead would go a long way here). Also, a sample of 2 out of 2 - does a trend make.

A letter or email is certainly in order here.....

05-15-2011, 03:45 AM   #15
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QuoteOriginally posted by interested_observer Quote
In that this is a replacement copy for the original - with the same problem, I would write to Zeiss directly and ask them if they could help out with an explanation. The lens is expensive, and with Zeiss' reputation for build, lens quality, and design - I would have to think that its not fungus and thus some sort of cleaning residue. If that is the case, then there is a whole set of questions concerning quality control of the build process and what is acceptable for the final inspection, etc.

Even if it does not currently affect the IQ, what does it do to the future resale value - rather than any appreciation, might you have to take some level of a price reduction (a letter of explanation on Zeiss letterhead would go a long way here). Also, a sample of 2 out of 2 - does a trend make.

A letter or email is certainly in order here.....

Thanks for you advice, interested_observer.

Yes, indeed it is a replacement copy. I had already contacted Zeiss with regard to the problem on the first copy and a very helpful and sincere Zeiss representative had advised me to send it in for cleaning or replacement by the dealer (B&H). I was having high hopes to acquire a good copy for this replacement but realised it's plagued with exactly the same problem! I had contacted both Zeiss and B&H and expecting a reply on the next couple of working days.

I was willing to just live with it but you are right too. For a lens that is hefty in price and expected to last a life-time, I shouldn't be making compromises here. Ha. For whatever the spots may be, there's two possibilities: 1) either this is a wide-spread issue (based on the serial numbers) or 2) something went wrong in B&H's warehouse. I was leaning towards 1) initially but I have a strong feeling with 2) now since I couldn't quite find similar problems for this lens elsewhere. I mean, there would have been some hoo-ha if it were indeed a wide spread problem and this lens isn't exactly new too.

I am pretty tired trying to be a investigator to be frank actually. My final option is to try buying from another dealer and see how it goes. It's rather unfortunate here for me as trying to rectify the issue always incur some extra shipping, taxation, frustrations and delays. >:
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