Remove Coating

[Wolfgang AM]

I have bought some cheap APO Ronar 360mm/f9 process lens for experimenting. The flaw on it is that the coating is defective. It has a lot of matted speckles. I think this coating is worse than none and my intention is to polish it away.
What do you think?
Has anyone experiences in that?

[Mark Woods]

The "problems" might create an interesting unique lens. Have you shot any images with them?

[ic-racer]

If the areas are affecting the coating only, they might not have much effect on the image. If the areas are affecting the glass also, they might not polish out. My experience is the the chances of improving the situation by removing the coating are slim.

[Wolfgang AM]

No I did not take shoots yet - I would have to make a lens board first. But I think the lens would have at least less contrast or/and would be prone to reflections shooting towards strong light sources.

I tried out polishing the front lens of my scratched Xenar lens with good results. But this kind does not have a coating at all.

[Michael Kadillak]

Shoot it and see what the images it produces. You may be pleasantly surprised at the results. Use a shade or just watch flare and you should be fine.

I asked a professional lens technician this question relative to what look like degraded or irregular coatings and he said that I should not worry about it as I could not tell the difference. Scratchings on the lens is another story because polishing it out changes the optical properties of the lens. That said if the lens is not worth much I can see the rational for what the heck? Go for it.

That said I paid $100 to have what looked like the beginning of some fungus taken off of a 355 G Claron and the entire lens was cleaned, polished and re-collimated and it is like new. In this instance it was worth the price.

[Brian Ellis]

I've used lenses that had splotches in the coating and they were fine. I definitely wouldn't try to do anything about the coating until you've made some photographs under a variety of lighting conditions.

[Mark Sawyer]

I agree with Michael, Brian, and ic-racer. The only thing the coating does is reduce flare/reflections in the lens. It won't affect other optical characteristics like resolution, (unless it actually turns hazy, which I've never seen or heard of). Any coating reduces reflections better than none.