coating damage...

HuubL

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What is your opinion on coating damage? I recently got another Summaron F/2.8 35mm. The lens is in pretty good shape with clear glass, oil-free diaphragm blades, perfect mechanical functioning. Only problem is partial loss of coating of the front lens. I've shot a few photos with it but don't see any obvious problems.
 
if you bought the lens at a decent price, i would not worry or dwell on it.
many less than perfect lenses perform wonderfully.
go out and use that lens more and more and it could become your favorite lens.
 
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All lens damage can potentially affect an image.

I suspect that most times, the damage is not something that most people would notice in the final image. Perhaps a side-by-side comparison with a known-good specimen of the same scene taken at the same time under the same conditions would be of use determining how visible said damage might be.

My own experience is that several of my lenses with rather severe coating damage still do an outstanding job, and I cannot detect the coating damage in my resulting scans of negatives made with them. I'd love all my glass to be scratch-free, but some isn't, and it doesn't seem to make any difference that I can see.
 
Personally, the condition you describe would drive me nuts. However, I would agree with the posters above regarding the likely final image results; just keep in mind, in its current condition, the lens will always be hard to sell.
 
Just think, you could pay extra to get a CV 40/1.4 single coated to experience the same effect your getting with your lens - in other words not much. Early Leica lenses had very soft coatings. Damage to the coating increases flare so a good lens hood helps immensely. If not shooting into flare prone situations you'll prbably never notice the difference.
 
HuubL, that is a kickass lens. I found the front lens to be receded rather deeply and that design afforded a lot of flare resistance. In fact, I used my summaron hood rarely.
 
The place where coating does the most good is inside the lens between groups of elements. It keeps light from bouncing back and forth, reflecting from one surface to the next, and degrading contrast. The only time this can happen with the external surface of a front element would be if you stick a filter in front of the lens. It's unlikely that you'll notice any effects on your pictures with that lens.
 
I've used several lenses with varying amounts of damage to the coating at the front, and most have given satisfactory results. I did not compare those lenses with perfect samples. Results interested me, and I got what I wanted.
 
If I am well informed, all a coating does is to reduce the reflection on the glass/air interface (usually one gets a few percent reflection). This through an optic trick which requires the coating thickness to be 1/4 of the wave length of the light.

Al is therefore right; it is mainly important for internal elements, to prevent bouncing between the elements (this forming ghost images of bright lights).

All it may do on the outer element is get a little more light into the lens (unlikely to be noticeable)

Mad_boy
 
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