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05-20-2013, 11:57 AM   #1
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Cosina haze problem

Hi everyone,

I recently acquired the somewhat rare Cosina 55 1.2. I got it for a very good price so I really dont want to send it back, however upon inspection of the front element I found an issue. There seem to be these "formations" for lack of a better word. I do not think they are on the outside of the front element, even though no matter how hard i look they really do seem like they are. Either way, they are not scratches, but rather something else that cannot be cleaned.

http://s23.postimg.org/yn1losaaj/IMGP2258_small.jpg

Could this be haze developing underneath the front element? I've had that on another lens before, but it did not quite look like that. However, if you inspect it closely enough there is some evidence of fogging:

http://s17.postimg.org/jxnxvtbbz/IMGP2259_small.jpg
http://s8.postimg.org/bzd4fg6v9/IMGP2260_small.jpg

I tried to circle the problem areas. I apologize, but it seems some of those circles are a little off.

Lastly, it appears that some of the helicoid lubricant has migrated on one of the aperture blades:

http://s3.postimg.org/xsv52usmb/IMGP2261_small.jpg

So my question is this. Besides the slight amount of haze beneath the front element, could these "artifacts" be the result of evaporated lubricant that just formed into a weird shape or there is something else going on with the lens. Possibly with the coating? Again, I dont think it is on the outside of the lens (as the outside appears to be even and smooth) but no matter how close i look it is definitely on the front element. Thanks in advance for all the help!!

Edit:
This is supposedly the Cosina 55 1.2 optical formula:
http://3.static.img-dpreview.com/files/w/TS560x560?url=http%3A%2F%2Fs012.rad...oIP41oD31MAfM=
judging by the design and how the front element is not cemented to the second group, i suppose it is possible to develop haze right under the front element, right?


Last edited by oxidized; 05-20-2013 at 12:18 PM.
05-20-2013, 12:22 PM   #2
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Iksobarg's Avatar

Join Date: Feb 2012
Posts: 208
Well now you know why you got such a good deal.
Most would agree that you get what you pay for and or there almost always seems to be a trade off(?)

So, 1. Is the haze affecting your pics?
If so, can you live with it?
On the other hand I have no idea if such a lens can be opened/cleaned.
Good luck!
05-20-2013, 02:21 PM   #3
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Original Poster
Okay, problem has been resolved. If anyone is curious and has similar issue in the future, all you need is a rubber ring and take the front lens cover (the one with the name, aperture etc) and then you can unscrew a metal ring, which holds the front element. The artifacts were migrated lubricants and the lens is now clean. However, I noticed another issue with it. When you inspect the rear element, you can see some really weird stuff on the inside:

http://s21.postimg.org/a4lnoz3ev/IMGP1132.jpg
http://s3.postimg.org/n7gtuvm1v/IMGP1133.jpg

And these effects appear to be present in the bokeh circles the lens creates when you take photos with it:
http://s21.postimg.org/wgo1w3rwn/IMGP1123.jpg

I only noticed this because I had seen this before in a Flickr photo from another user:
All sizes | It's All I See | Flickr - Photo Sharing!

same exact artifacts. What do you guys think? Could it be that the rear two elements are separating?
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