[UVC Safety Warning] Huge fast 254nm photolithography lens

[Lou Jost]

1 hour ago, JMC said:

Yes, I used the monochrome converted d850 for my 254nm imaging. However my new little machine vision camera with its Sony IMX487 sensor will be taking over that job on the microscope.

So you think both of those are better than the Sirchie imager?

[JMC]

7 minutes ago, Lou Jost said:

So you think both of those are better than the Sirchie imager?

It depends how you define better. The Sirchie will be more sensitive, for sure, but I cannot use it for proper photography or my microscopy.

[Lou Jost]

6 minutes ago, JMC said:

It depends how you define better. The Sirchie will be more sensitive, for sure, but I cannot use it for proper photography or my microscopy.

Because the resolution and/or contrast is bad?

[JMC]

1 minute ago, Lou Jost said:

Because the resolution and/or contrast is bad?

Resolution, and I cannot connect it to a computer or control the settings for the image or save to a card (at least I don't think I can save to a card, I've never checked). It's fine for looking through though.

[Lou Jost]

Thanks, so I guess it is not a great solution.

[JMC]

39 minutes ago, Lou Jost said:

Thanks, so I guess it is not a great solution.

The main reason we got the cameras when we did, was for the lens and the 254nm filter. The lens was a 60mm quartz one and the filter a very good little 254nm one with great out of band blocking.

[lukaszgryglicki]

One question - can you provide some specs for this filter, I'm searching for *ANY* filter that can pass 254nm and then block everything else with OD5 or more. Also, need to add this, not angle dependent, ideally not dichroic.

If you know any such filter, then I immediatelly will check it.

 

[JMC]

18 minutes ago, lukaszgryglicki said:

One question - can you provide some specs for this filter, I'm searching for *ANY* filter that can pass 254nm and then block everything else with OD5 or more. Also, need to add this, not angle dependent, ideally not dichroic.

If you know any such filter, then I immediatelly will check it.

 

They didn't have maker's marks on them, but I seem to recall a few people thought they looked like ones made by Omega filters. They are dichroic and I have no idea about angle dependency on transmission. 

[Andy Perrin]

Yeah, the phosphor screen idea has never worked very well. That's what I meant about you really having to coat the bare sensor with the phosphor somehow. Ideally with spincoating, as they do for microfab, not with a hilighter!  

 

Omega can make a filter also, at what expense I am not certain, but probably a lot. I still think buying a used Krimesite is the cheapest way. Just toss the screen and put the filter on a converted Raspberry Pi like David's. The Krimesite's KSS lens is reportedly pretty decent at 254nm, although I wasn't that impressed in UV-A.

 

David's results can be seen here:

https://www.ultravioletphotography.com/content/index.php?/topic/4629-safety-warning-cicada-wing-in-uvc/#comment-46064

[dabateman]

The Sirchie kits we bought were 60mm Macro lens with build in filter slider, and an imager. The imager is just to view stuff, it has a place to put your eye and a C-mount.  Its not a camera. But if Jonathan wanted to save thousands of dollars,  he could have mounted the image using its C-mount to the microscope,  then attach a cheap regular camera to the eye piece.  

I used mine with a Panasonic Gm5 mounted to the eyepiece with a 30mm macro lens, set at infinity.  That recorded the full viewer image, since its green only, I set the Gm5 to monochrome. 

The imager isn't bad, it produces a flat image and the resolution isn't super. But with filters it can see from UVC to IR. 

[Andrea B.]

Editor's Note: I have moved this topic from the UV Lens Technical Data section to the Tech section. Yes, this is a very unusual lens, but the UV Lens Technical Data area is only for lenses which have been spectroscopically measured. 

[Lou Jost]

5 hours ago, Andrea B. said:

Editor's Note: I have moved this topic from the UV Lens Technical Data section to the Tech section. Yes, this is a very unusual lens, but the UV Lens Technical Data area is only for lenses which have been spectroscopically measured. 

Hmmm, we do know it transmits down to its nominal wavelength, and it represents a large class of "known good" deep UV lenses that people ought to be aware of....

[Andrea B.]

Hi Lou, perhaps you can write an entry for the tech section following the format there? It would be good to have an entry for this lens.