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karen denman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 26, 2004 - 08:51 pm: | 
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hi there!
i have a rollie 2.8e that i picked up on active duty in the navy in the mid-60's..... i went to sell it last month & there is a smudge spot on the lens! apparently in the coating? can i repair this probelm myself or do i need to contact a 'repairperson'? if so where would i find a good technician?
karen |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 27, 2004 - 09:18 am: |
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First, you should try to clean it with lens cleaning fluid (if you did not already). Then, try alcohol or lighter fluid. If the spot is not removable, apply some vinegar with a q-tip on it. Maybe it is fungus and it will disappear with vinegar.
If not, i.e. if the coating is damaged, there is no reasonable cheap way to repair this. |
Ezio
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 27, 2004 - 02:32 pm: |
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Winfried is (as always) correct, but if applying the various cleaning fluids on the lens does not produce any result, please note the the fungus or whatever may well be on the inner face of the front lens element, or on the front face of the second element. To check this you will have to remove the front element (I think there is conversation about this in this page, otherwise ask Winfried). |
karen denman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 27, 2004 - 03:35 pm: |
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winfried & ezio
thanks so much for the tips but alas- i've tried everything but vinegar--- & now that but to no avail )-:
so do you know where i can get this procedure done--- or get the stuff to do i myself????..........i can't believe after all these years of carefully storing this camera that this has happened........
karen |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2004 - 07:33 am: |
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Ezio, I have seen quite a few lenses with fungus which was on outer surfaces and could not be removed by usual lens cleaning fluid which mostly consist of tensides and/or mild solvents such as alcohol. For some reasons most species of fungus seem to be resistant to these, even to lighter fluid, but vinegar usually removes the fungus if it has not grown for too long time. |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2004 - 12:46 pm: |
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I don't think this is necessarily fungus, but probably a spot where the coating has been damaged or rubbed off. I have a couple of lenses with this defect.
So far as I know, the only real solution to this problem is "live with it". If the spot is small, it will have about zero effect on pictures taken with the lens. (Even if it's larger, it will have very little effect.)
You could have this repaired by having the lens coating stripped and reapplied, but this would cost a small fortune relative to the value of the camera. It's an option to consider if you are really attached to the camera and want to restore it to pristine condition. |
karen denman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2004 - 03:04 pm: |
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david thanks for your input--
so why is the coating even necessary? is it part of the optics sharpness?
karen |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2004 - 03:57 pm: |
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Good question.
No, it has nothing to do with sharpness. It actually increases contrast (the difference between dark and light parts of the scene as recorded on film) and reduces lens "flare" caused by bright lights (like the sun) shining on the lens. (Coatings also make lenses more efficient at transmitting light by reducing reflections from lens elements--the individual glass lenses that make up the overall lens.)
Lens coatings are more technically called "antireflection" coatings. They are a microscopically-thin layer of metallic material (such as magnesium fluoride) that cause light that enters the lens at an angle to "cancel itself out". So if there's a bright reflection off to one side of the scene, the coating reduces the amount of light bouncing around inside the lens, which would otherwise cause a loss of contrast in the image.
For scenes without such lights, uncoated lenses work just fine. (Most lenses made before WWII, roughly, were uncoated.)
Others can give a better scientific explanation of how coatings work, but this is the basic gist of it. |
karen denman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2004 - 09:35 pm: |
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-so if the coating has some smudging on it why wouldn't it be better to remove the coating!! & wouldn't a polarizing filter take care of the flaring you are talking about??
karen |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 28, 2004 - 09:46 pm: |
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Removing the coating is almost as difficult a process as recoating: you can't just take the lens down to your neighborhood camera shop and say "I'd like the coating taken off this lens, please".
Filters don't really affect flare because it's caused by light reflecting off the surfaces of the lens (actually, the glass/air boundaries of the lens). A polarizer might reduce it some, but it introduces its own set of changes to the image, plus it reduces the light by at least a stop or more, so it can't be used in place of lens coating. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 29, 2004 - 08:08 am: |
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I think removing a (damaged) coating completely is a rather cosmetical method. Some people want to see an even shine (or reflection) on their lenses, and so they remove a coating which has lots of damaged spots. If the lens is still clear when looking through it, there is no technical need to remove a damaged coating. |
karen denman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 29, 2004 - 01:09 pm: |
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winfried
thanks again-- so what you are saying is that it might not effect the quality of the negs at all???? i have a very hard time seeing the smudging (i'm using the 'smudge' term for lack of a better description)...... i have to be in the very bright light & at just the right angle---- & even then it is difficult to see!it is not clouldly ---- almost like water spots?
karen |
David Nebenzahl
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 29, 2004 - 03:12 pm: |
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Based on your description of the defects, my advice is "don't sweat it". Your pictures will be fine. (Try taking some to see for yourself.) |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 01, 2004 - 11:36 am: |
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Karen, yes, I think you will have to BELIEVE that there will be any visible difference between negs shot with a lens with intact coating and those shot with a lens with minor coating defects to see them, but I don't think you can prove that there is a difference.
Coating defects such as tiny spots, cleaning marks etc will have more effect on the (selling or buying) price than on the results with those lenses. |
karen denman
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 01, 2004 - 02:16 pm: |
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thanks! for the info--- now onto ebay to sell this camera that i haven't used but a couple of time in all the years since acquiring it!!
when i was on active duty we went from speed graphics to 35mm w/o stopping in between!
karen
(thanks again!!) |
Stuart Willis
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 09, 2004 - 04:33 am: |
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I have a Rolleiflex 2.8 E (Xenotar) and it came to me with front element coating damage.
It is not a big deal to remove the front element and have it polished and recoated.
On a good camera such as mentioned it is worth the moderate expense of around US$25. There are plenty of optical labs which can recoat lenses.
Hope this helps
Stuart Willis |
