Removing lens coatings for better UV response.

[Doug A]

Recently, another website poster mentioned sanding the front lens element to remove coatings. A fair number of "accidental" UV lenses are now known. I was under the impression that sanding lens elements was outdated. Is this true, or are people here still employing this modification?

Thanks,

Doug A

[dabateman]

I think you might actually decrease the UV transmission if you removed the coating. But would depend on the coating. Sadly lens manufacturers don't tell us all their preparatory lens construction information. 

Roughly it would be better to use a known good lens, than hoping to improve a questionable one with cesium oxide polishing.

 

That being all said I bought a mint condition Wollensak 25mm C-mount lens in original box with original filters. It was said to pass UV well. Mine didn't pass anything below 400nm. So I took the four elements out and polished them. Now it does pass UV, but definitely not the best of my collection. 

[Stefano]

Coatings might decrease UV transmission and maybe a bit of UV reach, but if the glass the lens is made of (especially the flint elements) doesn't pass much UV, there's not much that can be done.

[Lou Jost]

For more complex lenses, it is also risky to remove and replace elements without precise means of testing centration during re-assembly.

[Doug A]

Thanks to everyone for the info. Figured most UV photographers had progressed past removing lens coatings.  UV photography has improved a lot in 20+ years. 

Thanks,

Doug A