Looking for UV photo of various camera lenses showing good uv lens vs a non uv lens.

[Mark Jones]

Everyone has seen UV photos of regular eye-glasses looking like sunglasses.

But I've never seen a UV photo of camera lenses. Specifically what an old 35mm f 3.5 lens might look like compared to a modern lens with coatings. How much lighter does an uncoated 35mm really look?

 

Just for my own satisfaction, if anyone has such a photo please post.

[Andrea B.]

We have some photos here showing some variation of UV-capability of lenses. Let me try to find the links. :)

[Andrea B.]

https://www.ultravio...sts-some-links/

This link has links to a summary of informal lens transmission tests amongst which are transmission tests which use reflected UV photos of the ends of the lenses. The lenses having better UV transmission are of course brighter and with much less false colour cast.

 

 

The UV photos of the lenses occur in the following three Pinhole Tests. The fourth link contains my attempt to write up a summary the Pinhold Test and also contains some UV images of lens ends. It is a relative method, but does yield some info about UV capability of a lens.

 

Hornblende: Pinhole and Relative Brightness

01 Apr 2017

http://www.ultraviol...dpost__p__15820

See also A.S.: Pinhole and Relative Brightness

08 April 2017

http://www.ultraviol...dpost__p__15941

OlDoinyo: A quick-and-dirty transmission test using a pinhole

http://www.ultraviol...dpost__p__10955

 

See also Andrea B.: Pinhole Test Protocol Summary 10 Apr 2017

http://www.ultraviol...dpost__p__15964

[Mark Jones]

thanks those are some good examples.

[Timber]

I think what Mark is looking for is the actual lenses photographed in UV... And that's an interesting project idea. Like how an old, scratched lens looks in UV? Will the UV spectrum bring those scratches out more than visible? How about fungus? Can we see how much damage fungus done for a lens in UV? Oooh... exciting! :)

[Andy Perrin]

Haha, I think dabateman got one of the UV-C imagers yesterday, so maybe he'll image them for us in UV-C. (I got one too, but I'm more interested in swapping out the fluorescent screen and making a SWIR camera.)

[Andrea B.]

I think what Mark is looking for is the actual lenses photographed in UV

 

Those *are* actual lenses photographed in UV.

[dabateman]

Timber,

I think Andrea second and last link was exactly what he wanted.

But looking at the images and the recent quest for plastic color standard thread. I wonder if we all have lenses that when placed in front of PTFE would provide the false, blue and yellow?

[Andy Perrin]

Dabateman, I can’t tell if you are kidding. The idea for the color standard is to have a reflective material like the Color Checker things. If we want false yellows by transmission, the Sparticle has that covered.

[dabateman]

Nope, just tired and not thinking threw.

Also a stack lenses assembly would be crazy huge and completely impractical.

Small reference target that can be easily dropped in and out of an image would be best.