[SAFETY WARNING] UVC, UVB, UVA Monochrom Acorn Series

[Andy Perrin]

Cadmium, the blocking of the filter is unknown, but it is definitely a 253.7BP25 filter (as deduced from the label that says as much on the side):

 

We don't know the peak transmittance either. That said, the device could not work for its intended purpose as a crime scene imager if it was transmitting too much UVA/UVB, which would be plentiful under daylight conditions where the device is meant to be used.

[Cadmium]

I would be extremely cautious of those UVC lights. I don't think they are being used in a safe way in those videos. If UVA can cause kateracks and skin cancer, and UVB is very scarce in out atmosphere, then UVC is something to stay away from.

[Cadmium]

Cadmium, the blocking of the filter is unknown, but it is definitely a 253.7BP25 filter (as deduced from the label that says as much on the side):

 

We don't know the peak transmittance either. That said, the device could not work for its intended purpose as a crime scene imager if it was transmitting too much UVA/UVB, which would be plentiful under daylight conditions where the device is meant to be used.

 

Well then... why didn't you say that to begin with, that was my question.

[Andy Perrin]

I thought I did?

[Cadmium]

I would suspect the lens on that would work well for UV, depending on mounting and such...

[Andy Perrin]

It's a quartz lens! It does indeed work nicely, albeit with quite a bit of chromatic aberration in UVA.

[Cadmium]

Oh well then... :-/

[dabateman]

Yes sorry, what I call the KSS 60mm Macro, is a quartz 60mm f3.5 lens with a C-mount.

It can be adapted to m43rds and Sony E-mount cameras. You could also maybe try it on a Nikon Z-mount, but it doesn't cover an APS-c sensor, just covers a m43rds sensor.

 

Just ran a quick test with a Wratten 2E filter. Its black on the back of the imager when using the 253bp25 filter. However, its not with the clear or no filter. So the phosphor imager can see into 400nm.

I am not sure what the green color of the phosphor screen is, so that would be the up conversion limit. I will have to test with more filters.

 

Also I will add a UVC light warning. I forget anyone can read this.

I now have a touch monitor in my work space connected to a computer upstairs using 25 feet USB and HDMI cables. I can tether the camera to the monitor usb ports. So I can setup things in the basement and then run upstairs to play with things.

 

What I would love is an Autofocus quartz lens. That would be ideal.

[Cadmium]

David, My question ("What filter are you using for the 253 image") has been resolved with the 253.7BP25 specification.

That was all I really was questioning.

I trust you have tested that bandpass, so I am a happy camper now. :-)

Thanks.

[JMC]

David, nice set of images.

 

I have now received my Sirchie camera with the lens and filters, and I will at some point be doing some tests on it. However I do not have a 254nm lamp for doing actual imaging work with it. As folks have said on here, it's not a light source to be messed about with lightly. I do have a mercury xenon lamp which does produce some light at 254nm, however it also produces a lot of UVB and UVA. I should however be able to get the transmission spectra of the filter down to 250nm, and the lens down to 280nm with the kit I have.

[Cadmium]

I am also curious about the other filters in the holder. Are there three, four filter?

Would someone list the labels on the sides of each filter, or stack them all on a table and take a photo of the labels?

Thanks. :-)

[Andy Perrin]

Cadmium, there are only 2 filters, and the other one is just a transparent window.

[dabateman]

Cadmium there are only two filters the 253.7bp25 and the other filter acts like a WG280 filter letting in even the light from my 303bp10 filter. It might be fused silica for all I know.

So just to correct the lens, as it seems to need it to focus correctly.

[Andrea B.]

Slightly Off Topic: THANK YOU, David, for the warning words at the beginning of your post about UVC. I'm going to embolden them. I do not encourage experimentation with UVC because I don't think most folks can take the proper precautions. I know you can because of your laboratory and science background.

[Cadmium]

Yes, Thank you Andy and David, two filters, one is clear...