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UltravioletPhotography

Solar spectrum lens test - Olympus M.ZUIKO DIGITAL 25mm f1.8


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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.

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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?

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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.

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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.

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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.

 

post-192-0-91124500-1527965979.jpg

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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.
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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.

 

post-192-0-91124500-1527965979.jpg

 

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.

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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.

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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.

post-24-0-61182700-1528141413.jpg

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.

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