Dmitry Posted June 2, 2018 Share Posted June 2, 2018 Gear used:Olympus e-pm1 body full spectrum converted myself.Olympus 25 f1.8 lens.More details in index topic no filter zwb1 zwb1+qb21 zwb2 zwb2+qb21 zwb3 zwb3+qb21 Link to comment
Cadmium Posted June 2, 2018 Share Posted June 2, 2018 It looks like all of the stacks are leaking red/IR. Link to comment
Dmitry Posted June 2, 2018 Author Share Posted June 2, 2018 Not really all. Far right part of spectrum is 2x magnified UV part. Second order spectrum. Link to comment
Cadmium Posted June 2, 2018 Share Posted June 2, 2018 Well, you would need to delineate that for me then. I need to know where Red/IR stop so I can see what is what.But... even if the IR cuts off where I think it does (comparing with the non-stacked example), then yes, all of the stacks look like they are leaking. Link to comment
Cadmium Posted June 2, 2018 Share Posted June 2, 2018 Yes, that was about what seemed to match up comparing to the non-stacked examples.In that case, on this page, then the zwb2 stack 'may' not be leaking... the other two look like they are using that separation.What is the range of the UV to IR? What nm dose the IR end at? What nm doe the UV start at? Link to comment
Dmitry Posted June 2, 2018 Author Share Posted June 2, 2018 What is the range of the UV to IR? What nm dose the IR end at? What nm doe the UV start at? Good question but it outside current lens testing goal.I have plan to test many filters and stacks on single lens. Need to find best copy. Link to comment
Cadmium Posted June 2, 2018 Share Posted June 2, 2018 Yes, it is a good lens comparison method, but it doesn't show the depth nm unless you put reference markings on it.Also, in the case of leaking, unless we know the upper IR limit, we can't know the leak limit. Link to comment
Dmitry Posted June 2, 2018 Author Share Posted June 2, 2018 Two very close dark lines are H and K Fraunhofer lines, wavelength is 393.366nm and 396.847nm.Next to left is L line, wavelength is 382.044nm. Link to comment
Cadmium Posted June 2, 2018 Share Posted June 2, 2018 OK, why not just use NM numbers. And a UV and IR limit would be good. I don't know what the use is of the 2nd order, just interested in the IR cut off. Link to comment
Dmitry Posted June 2, 2018 Author Share Posted June 2, 2018 I used this article as reference https://en.wikipedia.org/wiki/Fraunhofer_linesThere is no use for 2nd order, just can't ignore it. You can estimate L` line is at 2*382nm position. Link to comment
Andy Perrin Posted June 2, 2018 Share Posted June 2, 2018 For the IR cutoff, it would be better to have an IR pass filter? Link to comment
Dmitry Posted June 2, 2018 Author Share Posted June 2, 2018 I can try B+W 091 filter to check IR only part in filter stacks test. Link to comment
JCDowdy Posted June 3, 2018 Share Posted June 3, 2018 Two very close dark lines are H and K Fraunhofer lines, wavelength is 393.366nm and 396.847nm.Next to left is L line, wavelength is 382.044nm. Do you think you are detecting a faint N (358.121) line? I suggest you see if you can resolve the Hg emission lines at 365.015 and 334.148, 313.155 is probably being absorbed. There is limited utility if you cannot resolve shorter than ~360 as most lenses even marginally useful for UV transmit at least that short. Link to comment
Dmitry Posted June 3, 2018 Author Share Posted June 3, 2018 I think its M line (missed from wikipedia), M line is 373.5nmReference article in Russian - http://www.astronet.ru/db/msg/1173351/chapter36.html Or search for original text from "Astrophysical quantities" Book by Clabon Allen Link to comment
dabateman Posted June 4, 2018 Share Posted June 4, 2018 Dmitry,I think John was asking if you have seen any Hg lines? If not than none of your lenses are useful for uv photography. Just seeing to 380nm is extremely limiting. You would need a Straight edge u filter to get the most out of your lenses and still be confident that your seeing uv.Maybe good to pickup one cheap known to be good uv lens. Like the kuri 35mm f3.5 or the Nikkor EL 80mm old metal enlarger lens. I recently got an EL-80mm for $25, so they can be had cheap. You then need to add focus helicoid (70mm is film plane) and filter adapter.Once you have a good known uv lens, then test it using your setup to confirm you could even detect a good uv lens. Otherwise you may be missing something. Link to comment
Dmitry Posted June 4, 2018 Author Share Posted June 4, 2018 At least T-43 lens shows 358nm Hg line. Link to comment
JCDowdy Posted June 4, 2018 Share Posted June 4, 2018 Yes, your T-43 lens is showing a good deal of additional false color on the left and what appear also to be shorter wavelength Fraunhofer lines.Please label the Fraunhofer lines with their respective wavelengths. What I was suggesting however is that you use a low pressure Hg lamp to image Hg-I UV emissions lines. One of the small Pen-Ray sources for example or something similar. Link to comment
Dmitry Posted June 4, 2018 Author Share Posted June 4, 2018 My friend have Hg UV lamp and I want to select lenses and filters for new test. Link to comment
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