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11-16-2014, 03:02 PM   #1
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Fungus 50mm f1.2

Do people think this is worth buying for $240 dollars (with free fungus-infected M28/2.8 thrown in?!)





11-16-2014, 03:11 PM   #2
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Ewwww, no, that's a pretty bad case...
Fungi eat at the coatings, and in some cases are able to etch the glass "thanks" to their acid refuses...
Even if you can clean it, you'd have an abysmal IQ, since fungi are present not only on the front element but on the rear element as well...
BTW the price is not so low... you can probably find an ok one for that sum, if you look hard enough...
11-16-2014, 03:13 PM   #3
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Oh, I am sorry but I would have to agree with LensBeginner that the fungus has very likely eaten grooves into the coatings. If it was $50 it might be worth a gamble.
11-16-2014, 03:15 PM   #4
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I'd pass on that too.

11-16-2014, 03:20 PM   #5
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The filaments of fungus show the reproductive stage. The fungus has digested something that was on the glass and probably permanently etched the elements.
11-16-2014, 03:23 PM   #6
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I'd like to add that when the fungi only grow at or near the margin of the lenses the effect on IQ can be minimal, especially on APS-C.
On this one you have a pretty bad growth which completely covers the rear element.
I've also recently seen some test regarding dust, scratches, even pieces of paper and cracks on the front element, with minimal effects on IQ. On the rear element I'd bet the effect would be way more visible...
11-16-2014, 03:26 PM   #7
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Keep an eye on that serial number so you don't buy it later after the seller cleans it and tries again.
11-16-2014, 03:27 PM   #8
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I saw it on eBay the other day. Being on the lookout for a super-fast 50 ( I know silly me, having already TWO 50mm f1.4 !) - I also considered to get this and have it serviced but the case seems to be quite severe so I passed on it.

11-16-2014, 03:37 PM   #9
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I know that the lens serial number database is for owners, but it may be helpful to folks in the future to log this one as a fungus case, so as AquaDome posted, it does not get cleaned and passed off as a good copy.

Just a thought....

11-16-2014, 03:39 PM   #10
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QuoteOriginally posted by interested_observer Quote
I know that the lens serial number database is for owners, but it may be helpful to folks in the future to log this one as a fungus case, so as AquaDome posted, it does not get cleaned and passed off as a good copy.

Just a thought....

An anti-scam database? I like that idea!
11-16-2014, 03:50 PM   #11
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QuoteOriginally posted by AquaDome Quote
Keep an eye on that serial number so you don't buy it later after the seller cleans it and tries again.
What would be wrong with that ? It should clean up easily. But it is probably not worth $240.
11-16-2014, 04:21 PM   #12
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QuoteOriginally posted by LensBeginner Quote
An anti-scam database? I like that idea!
The idea is silly in my opinion - what stops one from taking the front ring with serial number and putting it on a good copy which he will keep, and then putting the other serial number on a faulty copy and selling it as a good one? In the end if lens had been cleaned with no trace - it probably would be perfect, but if fungus was still there or had etched the glass - one would see that much easier from good photos than going through any database. And good photos for me is a mandatory when I buy online - same as a reputable seller than I can trust. Getting lens with issues - like this fungus here - would need to really be balanced with a low price = low risk rule imho..
11-16-2014, 05:56 PM   #13
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You are looking at a weeks work of dis-assembly, cleaning and lens re-cementing right there. A rarer lens would warrant such treatment, but the K 50mm f/1.2 is more common lens, more common than the Noct Nikkor - which is a lens that would actually be worth restoring as only 12,000 of them were ever made.
11-16-2014, 10:33 PM   #14
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QuoteOriginally posted by dcshooter Quote
No, it would not take anywhere near that long , and to suggest so is quite frankly laughable. There is zero evidence of separation from that photo, and that is the only thing that would make it take anywhere near that long, and that is if you use Canada balsam as your cement rather than UV cured synthetic.

If the lens elements are not etched (and it could be the case, since Pentax coatings tend to be much more resistant to etching than most others), it would take 1-2 hours tops in the hands of an experienced lens technician to do a full CLA with fungus removal on a simply constructed lens like this. . Estimated time if I were doing it: 10 minutes for disassembly, 15 minutes for cleaning the elements, 15 minutes for a good scrub and relube of the helical (the fungus can and does feed on the helical grease), 15 minutes for a good alcohol/acetone dip of the internal mechanics to clean and kill fungus and a scrub of the barrel components with hot soap and water, followed by 15-30 minutes for reassembly. Once cleaned, there would be no perceptible difference in optical performance.

To put it in perspective, I was able to do a CLA and anodizing strip, re-anodize and hand-coloring on this very model of lens for a PF member in just under 3 hours.

Now if the elements are etched, there is no amount of re-cementing that will do anything to help it. The spots I am worried about are the little "dots" in the middle of the webbed patterns, as that is where it is most likely to have been etched, but I've successfully cleaned SMC coated lenses that appeared just as bad as this.

For $240, it might be worth the gamble, since the exterior looks to be in great shape - If it's optically irreparable, you could probably part it out and make most if not all of your money back, but it might take a while. And that's not considering the value of the 28mm. If it cleans up successfully, you are looking at doubling the value. At $50 less, it would be a no-brainer. And remember, even with etching, once the webbing was cleared out, the performance hit would likely be nearly imperceptible, so if you are not planning on re-selling, this could be a very affordable way to get to 1.2.

My advice is to contact the seller and see if he'd accept an offer of $150-$175. And go for it.
QuoteOriginally posted by dcshooter Quote
My advice is to contact the seller and see if he'd accept an offer of $150-$175. And go for it.
Yeah, the original asking price is a little too high with this bad a case of fungus. The waste products of aerobic (oxygen breathing) aren't usually too bad about etching. However, Anaerobic fungus has nastier waste products. When a lens has this developed of a case, there is a higher chance (if the lens is well sealed) that the aerobic fungus consumed all the O2, leaving a good environment for the nasty stuff to grow. Given the lens model and severity, this one looks risky.
11-16-2014, 11:42 PM   #15
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I recently bought such a lens in very good condition with 340USD (+ shipping + duty). This was the lowest price that I found after a while of searching on eBay (actually at the beginning of the search, I wanted to buy Porst 55mm 1.2 lens). The fungus lens presented here is priced too high.
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