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UltravioletPhotography

Resurrecting an Old Lens Test (Mostly Nikons)


Andrea B.

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This old 2009 lens test has long since been mostly lost to the internet. I found the original fotos today while prowling some of my drives and decided to look again at the results by pulling the raw composites with Raw Digger.

 

These examples might be of some interest as a couple of the Nikon AIS lenses look almost useable for UV. By looking at the raws we can see where some lenses might have benefited from slightly shorter or longer exposures. But I wouldn't judge these lenses by the actual exposure times because the fotos were made indoors with a single-chip UV-LED torch and with different focal lengths. The relative exposure times are more useful in finding which lenses might have UV potential under better illumination such as strong sunlight and/or a UV-flash. So take it all with a grain o' salt, OK? ;)

 

Equipment: Nikon D200BB + BaaderU UV-Pass Filter + Nichia 365nm UV-LED

Exposure: f/11 @ ISO-400, mostly. In a couple of cases I forgot and used f/8, but added the equivalent data.

Subject: Rudbeckia hirta, a classic UV-bullseye flower.

 

I have to point out that I was terrible at getting some of these lenses focused. Isn't it nice we now have Live View for such tests? Please don't let the lack of sharpness sway you because it is only my fault not the lens's fault.

 

If you expand your browser, these will appear in blocks of 4.

 

Pretty snappy exposure times, although that 35/1.4 probably needed 1".

And the 28/2.0 probably needed 2".

lens_Nik35-1.4ais_BaadU_365uvLed_100809_32707raw0101.jpglens_Nik50-1.8ais_BaadU_365uvLed_100809_32685raw0101.jpglens_Nik50-1.2ais_BaadU_365uvLed_100809_32676raw0101.jpglens_Nik28-2.0ais_BaadU_365uvLed_100809_32695raw0101.jpg

 

Note our old friend the Noflexar is in this batch.

Added: I'm not sure the Noflexar belongs in this test set because I might have had it extended thereby cutting down on the light and giving it this somewhat anomalous exposure time. I simply don't remember.

lens_Nik24-2.0ais_BaadU_365uvLed_100809_32691raw0102.jpglens_Nik45-2.8P_BaadU_365uvLed_100809_32710raw0101.jpg

lens_Nik58-1.2Noct_BaadU_365uvLed_100809_32718raw0101.jpglens_Novo35_BaadU_365uvLed_100809_32582raw0101.jpg

 

The next 3 lenses really won't do at all in UV.

That the modern 24-70 coated zoom doesn't work well for UV is no surprise, of course.

The Micro-Nikkor is really quite terrible! It's amost like you cannot force the UV through it.

Note that I have incorrectly named the file for the 20/2.8 as 'AIS', but the text correctly shows 'ED'.

lens_Nik24-70-2.8afs_BaadU_365uvLed_100809_32727raw0101.jpglens_Nik20-2.8ais_BaadU_365uvLed_100809_32657raw0102.jpg

lens_Nik60-2.8Micro_BaadU_365uvLed_100809_32627raw0101.jpg

 

Just for grins I tried my Rodenstock XR-Heligon using the 430 UV-pass filter. This Rodie is fixed at f/.75 and has no helicoid. Looks like it could have used about a 4" exposure instead of this blowout 6". It did record a bit of the Rudbeckia's UV-signature in spite of the leaky 430.

lens_Rodenstk50-.75XRHeligon_BW430_365uvLed_100809_32648raw02.jpg

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Nitpicking: The correct designation is 'Nikkor' not Nikons for these lenses. Unless you have the 50 mm f/1.8 SE which should be designated 'Nikon'. Be aware that there is a Nikkor 50 mm f/1.8 AI or AIS variant as well. Nobody says this lens range is simple to get the nomenclature overview of.

 

Anyway, you prove the fact that virtually any lens can exhibit a UV image if sufficient light is pushed through it either by opening up the aperture, or extending the exposure time. However, that in itself won't entail a satisfactory UV record as many lenses really don't do well in UV in terms of sharpness and low levels of optical aberrations. We also have to allow the fact that any UV going through these lenses won't be into the deeper sub 350 nm range; the Noflexar being an exception of course. However, even down to say 370 nm or slightly below will make UV-dark patches of flowers appear under appropriate UV illumination with the better UV bandpass filters attached to the lens.

 

Interestingly, your lens test confirms the usefulness of some Nikkors also deployed by me for special UV work: Nikkor 35 mm f/1.4, Nikkor 50 mm f/1.2 (either AI or AIS versions will work, but the AI appears to be in the lead of the two). The Nikkor 50 mm f/1.8 AI isn't bad either and the same applies to is economic cousin, the Nikon 50 mm f/1.8 SE. In fact, the SE range has several appealing candidates for UV work. The Nikon 100 mm f/2.8 SE is pretty good in this respect.

 

I use the opportunity to mention the Nikkor 85 mm f/1.4 AIS, which in fact is performing super sharp in UV, even down to matching or improving the performance of the UV-Nikkor. However, it will not go very far into UV, so for all ordinary uses the UV-Nikkor is the better choice. Also note the 85 requires internal filtering due to its huge 72 mm filter thread size. You can make do with 62 mm filter sizes at least with the lens on a DX-format camera, however. Using the 85 on say a 43 body, enables rear filtration to be inserted and this neatly eschews the need for large frontal filters.

 

Among the wide angles, the 24 mm f/2 Nikkor responds quite well to UV, but you need to stop it fairly far down to get anything useful in terms of sharpness form it.

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Pretty snappy exposure times.............

Note our old friend the Noflexar is in this batch.

 

Am I reading correctly that the Noflexar, at 4", required the longest exposure time of the first eight?

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That would seem to be the case. BUT, recall that the Noflexar is extendible. If I had it extended that would tend to cut down on the light.

 

Hmmm, maybe I should kick the Noflexar out of this test?

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If I were to repeat this test outdoors in good sunlight using the D600, I wonder if I should attempt to keep the distance the same across this range of lenses or is I should keep the subject size the same? I suppose I could just do both series because this is a question I always ask and for which I never remember the "correct" answer. :D :lol: B) ;)

 

I don't think I'm eager to do any more tests however. I am rather tested out. :P :P :P :P

And I never did get around to the Hanimar/Lentar/Funkadar 135mm tests.

Oh well.

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It has a field of view not to dissimilar to the other 35mm so it seems not to have been extended.

 

I do notice a bit of vignetting of your LED beam on most, except the Noflexar, perhaps the LED was farther back?

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Those are square crops which were resized (up or down) to 400px widths. The fields of view varied.

 

The UV-Led sat in a clamp arm thingie at whatever was the given distance from the flower.

 

Vignetting is often caused by step rings for front mounting the BaadU. Best to rear mount it when vignetting is a problem.

 

I think the simple conclusion from this old test is exactly what Bjørn said, the old manual focus Nikkors might be useful for UV work.

 

This was prolly a cr@99y test. Maybe I should delete it.

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This was prolly a cr@99y test. Maybe I should delete it.

 

Nah, why delete it now, it is interesting.

 

Another, perhaps obvious, point is the 365nm LED is in the upper (longer wavelength) ~half or ~third of the Baader-U passband.

 

It is entirely possible that a lens could have both higher transmission on the long side of the filter and lower transmission on the short wavelength side of the Baader-U band. In other words a lens could be faster at 365 and still not transmit as deeply into the shorter wavelengths as the Noflexar.

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