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Infected Jupiter-37A
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PostPosted: Sat Mar 05, 2011 3:19 pm    Post subject: Infected Jupiter-37A Reply with quote
Hi guys! Been a bit since I have stopped by.

Well, I was waiting for this J37A lens to stop with the purchase frenzy all beginners seem to go through and start having fun!

The seller claimed it had fungi infection but since I was going to get for less than 30 bucks and given the love this lens seems to deserve among the vintage class I decided to take the risk.

Now I would like your opinion on if the infection is severly afecting image quality. The following are a couple of tests I did and later edited with Photoshop's default adjustments color-wise, contrast-wise and levels-wise so we could compare the original result with the edited one.

Physical evidence (white spots are fungi I believe):


According to the pics the seller had, they are located in the rear element. I have tried disassembling it but I was not able to get to it.

First comparison:


Second comparison:


Physical evidence was taken with the Yashica and the comparison shots were taken with the J37A (obviously), wide-open (ƒ/3.5) and I had to improvise for I haven't bought the adapter yet.

I also take the chance to ask anyone who has specific instruction for the disassembling of this lens since on how to reach the rear element (the massive chunk of cemented glass?) to apply some cold cream to see if the damn fungus would go away..

Regards


PostPosted: Sat Mar 05, 2011 5:18 pm    Post subject: Reply with quote
This is the best site that I've been able to find.
http://www3.telus.net/public/rpnchbck/lens%20and%20optics.html
I've read that the Jupiter 11 is similar in construction.


PostPosted: Sat Mar 05, 2011 5:53 pm    Post subject: Re: Infected Jupiter-37A Reply with quote
ChromaticAberration wrote:

Now I would like your opinion on if the infection is severly afecting image quality.


It looks like it definitely impacts color and contrast. A good sample should give you results closer to the photoshopped ones.


PostPosted: Sat Mar 05, 2011 6:05 pm    Post subject: Reply with quote
The non multi-coated 37A isn't THAT contrasty anyway. It's certainly not as contrasy as the Carl Zeiss Jena version, for example. See:

http://forum.mflenses.com/viewtopic.php?t=31562

But...it does look like it's struggling with the fungus. Try shooting a picture of the rear element with your DSLR with flash on. Leave the front cap on keep the background dark. Then we can see the real fungus infection Smile


PostPosted: Sat Mar 05, 2011 8:06 pm    Post subject: Re: Infected Jupiter-37A Reply with quote
ChromaticAberration wrote:


....

According to the pics the seller had, they are located in the rear element. I have tried disassembling it but I was not able to get to it.

.....

I also take the chance to ask anyone who has specific instruction for the disassembling of this lens since on how to reach the rear element (the massive chunk of cemented glass?) to apply some cold cream to see if the damn fungus would go away..

....



The rear element is easily removed. There's just one ring - it's obvious which one it is.

However perhaps you mean the rear element of the front group. The front optical block simply unscrews. Hold the very front of the lens - the short part in front of the aperture ring - and unscrew. This will provide access to the back surface of the rear element of the front optical block.


PostPosted: Sun Mar 06, 2011 12:08 am    Post subject: Reply with quote
ManualFocus-G wrote:
The non multi-coated 37A isn't THAT contrasty anyway.


Yeah those pics surely show that, less contrast for sure.

ManualFocus-G wrote:

Try shooting a picture of the rear element with your DSLR with flash on.


Fungus is not seen from the rear only from the front of the lens, maybe the seller was referring to the rear-front element. Anyway, a couple more:






sichko wrote:

However perhaps you mean the rear element of the front group. The front optical block simply unscrews. Hold the very front of the lens - the short part in front of the aperture ring - and unscrew. This will provide access to the back surface of the rear element of the front optical block.


I haven't been able to do so.. I have tried to force it a bit but it feels solid and won´t budge, I seen it disassembled in the seller's picks, including the infected element (a large chunk of glass), but I am afraid of breaking it really.
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