What to do about damaged lens coating?

woof woof

woof woof

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The coating on one of my lenses has been damaged when it was being cleaned (not by me) and the surface now has a very visible sort of zebra pattern on it. The front element is fine and is easy to remove and behind that there's a number of elements in a sealed group and it's the front one of these that the coating has been damaged on.

I haven't had time to use the lens yet so I don't know if this will have any noticeable effect on image quality although I did have a damaged lens years ago and that did show quite a bit in pictures when the sun was in the frame.

So, one thing I wonder is if cleaning all of the coating off is a good idea and if it is is this possible and what would I use?

Or maybe I could just use a lens hood more and avoid shooting with the sun in the frame.

Any views would be welcome.
 
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If the front element is flat — like it is the case with
long lenses — I would not worry… but if not than I
don't know for it did not happen to me yet.
 
Sorry, I should have said... it's a 35mm f2.8. The damaged coating lens that I'm sure I could see some impact on image quality with years ago was a 55mm f1.7.

When I get some free time and a sunny day I'll take it out and see what I can provoke but in the meantime I just wondered what people thought.
 
I had a lens that had a damaged coating on a convex front glass and it gave me a bright flare on all of my images, I eventually bought a scrapper and swapped the bits over however I did clean of quite a bit of the coating before repairing it and it was totally unusable even in low light situations so I would say that cleaning it all off would probably result in a buggered lens.
 
Ah. Oh dear... I hold off on trying to get it all off then and instead I'll keep my eye out for either a good one or one with mechanical failure but good optics.
 
You say you didn't clean it and it's an internal lens element that is damaged, was it sent away and came back damaged or did this damage occur before you got it. If it was sent away can you not claim against whoever damaged it as I assume it was dis-assembled?
 
Yup. It was sent away and came back like this.

I'm not going to argue with the "repairer" as they'll only say that the coating was degraded and it wasn't their fault which may be true even if I think otherwise. The zebra pattern seems to be a bit of a clue to them using something they should have but maybe I'm being too suspicious and unfair.

Since I got it back I've disassembled it and cleaned it without visibly affecting the remaining coating and I do wish I'd done it myself in the first instance but I am where I am with it now.
 
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Just a quick update...

I tried the lens today and looking at the evf it's as if there's vaseline on the lens and it's the same in the pictures and the lens is unuseable.

I wouldn't have believed that damaged coating would have this much effect as weren't lenses uncoated years ago... I wonder if this is because the coating is patchy and damaged and maybe it would be better with no coating at all. I don't know but what I do know is that the lens is unuseable now unless I want a picture that looks like it was taken through vaseline.
 
woof woof said:
Just a quick update...

I tried the lens today and looking at the evf it's as if there's vaseline on the lens and it's the same in the pictures and the lens is unuseable.

I wouldn't have believed that damaged coating would have this much effect as weren't lenses uncoated years ago... I wonder if this is because the coating is patchy and damaged and maybe it would be better with no coating at all. I don't know but what I do know is that the lens is unuseable now unless I want a picture that looks like it was taken through vaseline.
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Perfect lens for romantic portraits. :-)
 
MatBin said:
Perfect lens for romantic portraits. :)
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It'll replace those special effects filters I bought years ago :D

I'll keep the lens as it's in very good condition and I may come across one with good optics but a mechanical fault.
 
A couple of pictures, firstly the lens with the damaged coating and then a good lens...

DSC09836.jpg

DSC09849.jpg

That's pretty dramatic and I honestly never imagined that the damaged coating would lead to such a degradation in image quality.

Pictures without a bright window in the corner show just the same haziness.
 
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woof woof said:
A couple of pictures, firstly the lens with the damaged coating and then a good lens...

View attachment 123382

View attachment 123383

That's pretty dramatic and I honestly never imagined that the damaged coating would lead to such a degradation in image quality.

Pictures without a bright window in the corner show just the same haziness.
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I bought a 135 f2.8sf to do that. :-)
 
woof woof said:
I've never heard of that, what will it do?
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So a year back I was searching for ways to clean fungus (I bought a lens very cheaply because it had fungus as an experiment). I came across this article by zeiss that suggested polishing the glass with cigarette ash, the article said it'd help clearing both fungus and sort out coating irregularities (because fungus can etch into the glass+coating)

I didn't use this method, I simply used vinegar to clean my front element which worked wonders for me.
 
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nandbytes said:
So a year back I was searching for ways to clean fungus (I bought a lens very cheaply because it had fungus as an experiment). I came across this article by zeiss that suggested polishing the glass with cigarette ash, the article said it'd help clearing both fungus and sort out coating irregularities (because fungus can etch into the glass+coating)

I didn't use this method, I simply used vinegar to clean my front element which worked wonders for me.
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Thanks.

As I have nothing to lose I might give both a go and see what happens. It's a lovely lens but completely unsaleable as it is and although I found another and it should be coming this week it'll be interesting to see if vinegar/ash do any good.
 
woof woof said:
Thanks.

As I have nothing to lose I might give both a go and see what happens. It's a lovely lens but completely unsaleable as it is and although I found another and it should be coming this week it'll be interesting to see if vinegar/ash do any good.
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Exactly, if it makes it better then great and if it doesn't then you will have learnt something (maybe?).

Can I ask which lens it is so I can do my own research on it?
 
Minolta Rokkor 35mm f2.8 MC.

There are a few Rokkor 35mm f2.8's but this is the earlier one with the older metal body and also... poorer coatings which is IMO part of it's look and charm..

This one...

http://www.myfavouritelens.com/minolta-mc-rokkor-hg-35mm-f2-8-lens-review/

When ok it was my favorite old 35mm lens. Luckily I snapped up another on evil bay so I should be getting it next week. This lens has a different look to the later Rokkor MD 35mm f2.8 I had and f1.8 which I still have.

I also have the similarly built MC 55mm f1.7 which again has a very distinctive look.
 
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The cigarette ash will basically be a finer polishing compound, a bit like using toothpaste too.

If you’re getting the same low contrast/flare in low light too are you sure there isn’t an element reversed inside the lens?
 
stevelmx5 said:
The cigarette ash will basically be a finer polishing compound, a bit like using toothpaste too.

If you’re getting the same low contrast/flare in low light too are you sure there isn’t an element reversed inside the lens?
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I get the low contrast haziness no matter what I point it at. I'm sure there's nothing reversed. The very front one is curved but obviously so and once you remove that all of the others are in a sealed block so you can't really put anything back reversed.

Another picture, duff then ok lenses...

DSC09827.jpg

DSC09842.jpg
 
I personally think it’s a lost clause, try find another and don’t waste time trying to salvage it.
 
Raymond Lin said:
I personally think it’s a lost clause, try find another and don’t waste time trying to salvage it.
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I have another in the way and from the pictures it looks nice. I'll keep this duff one as the rest of the lens is like new so if I ever find a mechanically duff one or if anything goes mechanically wrong with the one which is on the way to me I can make one from two.
 
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