Checking my lenses for UV capability

[colinbm]

Thanks Ulf for this assessment, I'll keep it in mind, though I have no experience in this.

I got the instrument to learn more about UV & photography, not being overly concerned with IR as that is far easier to do.

Having said that I am interested in the full range of our digital cameras.

I am still waiting for an answer on why the short end of UV is truncated in Sunlight. I have nothing else to test UV this far in the UVB, but I am looking.

[colinbm]

I know I bought this instrument against some peoples advice, but I also bought it with some other peoples advice, too.

I didn't want a Lab Instrument to get absolute results, I wanted an instrument to get Field Results & to compare one lens against another, amongst other things, to see which was more suitable in our usage.

I am happy with my choice so far, but I have a ton to learn, if I'm learning that is good....;-)

[ulf]

Col-

 

I think your choice is OK for your set goals!

 

It is always good to know and understand the limitations of the equipment.

There might be some tricks to improve the results if we are lucky.

 

I have gradually improved my understanding while working with my spectrometer and light-sources.

With some luck some of that might be applicable on your device even if it is a very different animal.

[Andy Perrin]

In case there are any questions about the procedure for making the graph, it was this:

 

1) Put all the irradiance values together on one spreadsheet.

2) Divide each irradiance value (for all the lenses, and for the solar spectrum) by whatever value was at 620nm, a wavelength chosen because the irradiance had a strong signal at that point in all the graphs, and the transmissions were flat there.

3) Calculate the transmission by dividing the normalized irradiance with lens by the irradiance with no lens.

4) Repeat for each lens.

[Cadmium]

Seems like a random comment but yes.

I have fibers that are capable of transmitting 190nm to 1200nm, that ate 600um in diameter.

I tested my fiber optic cable I bought for my stereo and its about 400nm up.

I bought a filter wheel and it came with 2 fibers 77525 that are 1100um in diameter. They transmit slightly differently, but only above 340nm. They are rated to transmit from 400nm to 1500nm on the spec sheet.

So the fiber makes a huge difference.

Ocean optics also has a pdf somewhere that outlines the color codes and fibers.

 

But i wouldn't expect much below 400nm for a typical stereo, or Verizon grade optical fiber.

 

Not a random question. Remember, at one time he was using a fiber optic cable to transport sunlight from his roof top down to his blue box Surplus Scientific spectrometer.

http://www.science-s...s/spectrometers

So I was wondering if all fiber optic cables are created equal, and if possibly it, or some other element in that 'pipeline', might be attenuating any part of the delivered sun spectrum.

I understand that some fiber optic cables transmit a full spectrum, but might there be any question within that delivery system that could be altering the results?

It is part of the equation.

[Andrea B.]

Reed, thank you for that Schmitt chart. I used to have it, but wouldn't know where to look for it at this point !!!

[Cadmium]

Indeed, but that is a rather old and outdated chart version, being it doesn't have the Kuribayashi 35mm or the Focotar II 50mm, those would have been added many years ago, both being better than the Novoflex/ Noflexar lenses.