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Dragunov
Tinkerer
Username: Dragunov
Post Number: 125
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 11, 2008 - 08:19 pm: | 
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speaking of Soviet quality control, I'd like to say that it can be really shoddy. my Jupiter 8 (contax mount) had a metal shaving just under the front element, and how this escaped 'quality control' defies my imagination. it's awfully obvious if you cared to look. in any case, it bothers me and I had nothing (actually, math homework) to do, so I got out the small screwdriver and got to work. so I exposed them aperture blades. all the way there.
but before I re-assembled it partly, I wanted to dust off the element behind the aperture blades. okay. so I get the blower brush and... the coating looks spotty. strange. I use the lens tissue, and then what? I get streaks. it's time to freak out.
so, that's all and done, nothing I can do to reverse it. or is there? that's what i'm asking you lads. will this damaging of coating affect my pictures at all?
and here comes the strange twist... what's the best way to remove a lens coating without damaging the lens itself? why? i've yearned for an uncoated lens... this is my chance?
here is what i'm yapping about:
http://s117.photobucket.com/albums/o70/dragunov-svd/?action=view¤t=IMGP068 1.jpg
AHHHH!
cheers. |
Steve_s
Tinkerer
Username: Steve_s
Post Number: 137
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 12, 2008 - 01:54 am: |
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Are you sure it's not just greasy? What happens if you give it a gentle wipe with some lighter fuel? |
Glenn
Tinkerer
Username: Glenn
Post Number: 448
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 12, 2008 - 04:12 pm: |
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People make far to much fuss about odd bits of 'crap' floating around inside lenses, often ending up in your situation with a 'damaged' lens. Only rarely will these bits make their presence felt on the image.
Dump those lens tissues in the bin, few people know the correct way to prepare a tissue and end up scratching the coating. The correct way to prepare a tissue, is to roll it up into a tight cylinder. Tear the said cylinder in half - this will give you two paper cylinders, each with one soft fluffy torn end. You clean the element surface with the fluffy end - no risk of scratching the coating. However you should get yourself a couple of large microfibre lens cloths - use one for the initial clean to remove the grease and dirt (keep this cloth well washed), and the second for the final polish.
As for the surface condition of the coating - I have come across many Russian lenses with coatings that exhibit a very rough surface texture. Coatings that exhibit this tend to be rather soft and are easily damaged. If naphtha will not remove your marks you have damaged the coating.
You can polish off an old soft coating. Unfortunately these Russian coatings, whilst soft, are not like the original old coatings. If you do try and remove the coating, you are likely to end up with a piece of scrap. Even if you have access to proper lens polishing equipment, any alteration of surface curvature will compromise optical performance.
If you want an uncoated optic, get an uncoated original - there are still plenty of classics that you can pick up if you look around. |
Dragunov
Tinkerer
Username: Dragunov
Post Number: 126
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 12, 2008 - 08:51 pm: |
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perhaps it was harmless. probably, since my pictures were good. (some not so sharp, I think it was the developer's fault, light leaks as to be expected)
but could you let this thing
http://s117.photobucket.com/albums/o70/dragunov-svd/?action=view¤t=brick.j pg
sit in your lens and not take action?
how bad is this damaged coating and will I get more flare as a result?
thanks, all. |
Glenn
Tinkerer
Username: Glenn
Post Number: 449
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 13, 2008 - 04:55 pm: |
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In that lens, I would have certainly left well alone and carried on using the thing. Your 'all over unsharpness' has nothing to do with small amounts of rubbish inside the lens.
I cannot comment on the condition of the coating, or what the said damage might do to the image. I have a number of rare optics, that sadly have been abused by both storage and previous owners. They will all produce very acceptable results if you take into account the condition of the glass, when framing the image in relation to the lighting source. |
Dragunov
Tinkerer
Username: Dragunov
Post Number: 127
Registered: 10-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 13, 2008 - 08:21 pm: |
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thanks.
and hey! I was bored.
well, I learned a lot from a $20 camera. |
Glenn
Tinkerer
Username: Glenn
Post Number: 450
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 14, 2008 - 08:49 am: |
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Small price to pay for a lot of fun and useful knowledge! |
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