Shooting a lens with coating damage

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Scottboarding

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Hello!


I purchased a Canon LTM 50mm f1.8ii a few months ago that had a haze issue (so I thought) which caused some blooming on B&W and caused color film to be almost unusable. I took it to a repair shop and they said that it is coating damage, not haze, meaning there isn't anything I can do about it. Looking back at my negatives that came from the lens I noticed they're all very thin with virtually no shadow detail. I know it isn't my lab because I've brought them the same film stocks shot with different cameras and never had a problem. So I have a few questions.


1. Can coating damage/loss cause a drop in transmission of light? Sunny 16 has always been reliable for me but doesn't work with this lens.


2. Would a yellow or red filter help with the blooming and glowing issue?


I'm planning on picking up a 50mm f1.4 once I can sell off some other things, but in the meantime is there much I can do to shoot this lens more successfully?


Thanks!
 
Pictures of the lens would be very helpful.
I had old Leitz lens once with coating damage and it was not a big deal.
 
I recall I used to own a Nikonos 5 with its standard 35mm f2.5 lens which while new had a noticeable area of coating damage (missing coating) on the front element. (Never could get Nikon to do anything about it though). Point is it always flared like the dikkins when the sun was anywhere near the frame. I am pretty sure it was attributable to that coating damage.
 
1 no 2 no.

My rigid summicron had coating damage on the front element similar to what you describe. I sent the lens over to focal point lens in Colorado and they repaired it and recoated the front element. The lens performed perfectly after that and I regret selling it to this day.

Especially since the guy who bought it tried to disassemble it that evening after buying it to take a very minuscule piece of dust out of it tried to ask for his money back the next day when the lens was severely ****ed up. I was pretty angry.
 
If extensive enough, coating damage on a front element can cause lens flaring and reduced contrast. This damage appears as pattern of numerous fine coating irregularities/lines that coalesce. My rigid summicron also had this damage with reduced contrast and a hazy look to images. Re-coating and polishing (also done by John Van Stelton at Focal Point) remedied the problem: contrast markedly improved and images were clear.

Zeiss developed "harder", more resistant coatings for military application during WWII. After the war, other companies were able to use that coating method or something similar, but Leitz was unable to do this until the mid 1960s.
 
Scottboarding said:
I purchased a Canon LTM 50mm f1.8ii a few months ago that had a haze issue (so I thought) which caused some blooming on B&W and caused color film to be almost unusable. I took it to a repair shop and they said that it is coating damage, not haze, meaning there isn't anything I can do about it.
Click to expand...

More than likely, its not coating damage. The optical group just behind the aperture blades in the Canon 50/1.8 is quite well known for going cloudy. Whatever funky stuff Canon used in that optical group to achieve the desired refractive index causes the glass to corrode over time, so the damage is neither haze nor coating, its glass corrosion.

Kanto Camera in Kawasaki offers a replacement optical group made from modern glass. But its not cheap.

Yamazaki Optics in Tokyo, a place well known for lens polishing and recoating, won't touch Canon LTM lenses because, to quote Yamazaki-san, "the corrosion will just come back so its a waste of time/money to repair them".

There's nothing you can really do to improve IQ. Better off tossing the lens and getting something else.

Edit: I see I'm repeating myself - https://www.rangefinderforum.com/forums/showpost.php?p=2597248&postcount=7
 
I have very occasionally seen this problem with other Canon lenses, but the 50 f1.8 seems by far the worst offender, with the black ones possibly worse than the chrome. The later 50 f1.4 is a splendid lens and doesn’t appear to have the problem.

Cheers,
Dez
 
When you have a lens with coating damage - I have several Summars coated just after the war with some extremely soft coating that shows fine scratches - don't clean it thoroughly, but only wipe it quickly clean with a cotton swab moistened with lighter fluid. The longer you rub, the worse the damage becomes.


Erik.
 
John Van Stelton at Focal Point has been put of business for awhile. Curious if anyone else is doing the type repairs he used to do?
 
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