Sunday, January 30, 2011

Psychedelic Lilly - a UV and VIS comparison Noflexar 35mm vs EL-Nikkor 80mm

A really nice flower, a "Stargazer Lilly", so let's see how the beauty of that flower will look like through the well known Novoflex Noflexar 3.5/35mm versus the newly rediscovered older (chrome/black) 5.6/80mm EL-Nikkor enlarger lens in visible light, but also in invisible UV.

All shots were done at f8, ISO400, 1/160s using Xenon flash, exposure adjusted using flash power control and ND filters. UV shots were done using the Baader-U filter.

[click on image to see a larger one]

Here now a VIS-UV differential using the Noflexar 3.5/35mm:


and yes, quite a nice sharp lens with quite good UV transmission and some little focus shift.

and here using the 5.6/80mm EL-Nikkor:


Quite a sharp lens, even less focus shift and also quite good UV transmission.

For comparison here the VIS shot using the Noflexar 3.5/35mm:


and using the 5.6/80mm EL-Nikkor:


Finally now the UV shot using the Noflexar 3.5/35mm:


and using the 5.6/80mm EL-Nikkor:


Well, I am surprised to see, that the Noflexar gets slightly outperformed by the EL-Nikkor 80mm!

BUT: I tried the 5.6/80mm EL-Nikkor outside for infinity tests and unfortunately it seems to have a very prominent large UV hotspot which renders it unuseable for that...


P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, as me if you need an adapter ring.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Saturday, January 29, 2011

[UV] Lenses tested good for UV

This is simply a collection of links to tests I have done for various lenses in terms of UV transmission and UV focus shift. Some also contain IR tests. No specific order and no ranking implied. Only lenses tested I own; if one seems to miss, I simply don't have it.

• True Lenses for UV: UV-Nikkor 105mm, Coastal Optics 105mm, Hasselblad UV-Sonnar 105mm
• Lens Comparison: UV Nikkor 105mm, COSI 105mm, B&L 9"
• Carl Zeiss UV-Planar 4/60mm
• Schneider Componon lenses for UV
• Rodenstock (now LINOS) Rodagon lenses for UV
• Steinheil lenses for UV
• EL-Nikkor enlarger lenses for UV
• EL-Nikkor 3.5/63mm vs 5.6/80mm
• EL-Nikkor 75mm - 80mm - 105mm for UV?
• On EL Nikkors for UV Photography and a Myth
• EL-Nikkor 5.6/80mm lens without UV + IR focus shift
• EL-Nikkor 80mm vs 105mm UV and VIS comparison
• EL-Nikkor 80mm - old vs new
• Micro-Nikkor 105mm for UV photography? Not...
• Novoflex Noflexar 35mm vs EL-Nikkor 80mm UV - VIS comparison
• Wide angle lenses for UV
• Eight 35mm wide angle lenses tested for UV
• Petri Kuribayashi f3.5/35mm for reflected UV
• A comparative, subjective shootout of lenses for reflected UV photography
• A comparative, subjective shootout of Lenses for UV Photography ... Fluorescence
• Rudbeckia - a study of lenses for UV photography
• Transmittance of some Bellows Lens Heads
• Old Achromatic Quartz Fluorite Lens for Ultraviolet Photography
• Old Achromatic Quartz Fluorite Lens for Ultraviolet Photography (ff.)
• Hamamatsu A4869 UV lens f3.5/50mm for reflected UV photography
 
Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

How to determine the length of a focusing helicoid

I have been asked, if there is a way to simply determine the needed length of a focusing helicoid to reach infinity focus [when mounting for instance an enlarger lens, or lens without own focusing mount to a camera}.

Yes, it can be determined, if you have the register length ("Auflagemass" in German) for a given length. If not, measurements or an approximation have to be used.

Denote:

RLL = Register Length of a Lens
RLC = Register Length of a camera (Nikon, Canon EOS, 4/3 - you name it)
HLI = Helicoid Length at Infinity
AL = Adaptor Length (usually a few millimeters thickness only)

then:

HLI = RLL - RLC - AL

that also means that HLI cannot be negative and has to be at least some 15mm or so (shortest Helicoid I know of; but there is an exception). This also explains why with some lenses infinity focus cannot be reached.

If RLL is not known, the following procedure allows to measure it approximately:

Take a white sheet of paper, a ruler and your lens, hold the lens in front of the white paper in a darkened room and point the lens front with fully open aperture to the outside to a far away bright and contrasty object (can be the sun, but be careful not to burn the paper, or a hill against the sky) at least 100x further away then the focal length of that lens until you get a sharp image on that paper. Now measure the distance from that paper to the flange of the lens (end of the thread or mount (could be bajonet etc.) - not just the physical end of the lens!). This is approximately RLL.

If you want to use that lens for macro shooting, say at 1:1 magnification, then point the lens using the same procedure to a bright lamp (desktop tungsten works well) until you see an projected image which has the same size as the original lamp (us the visible lamp filament for instance (stepping down helps if the image is too bright). Keep that position and repeat the measurement at mentioned above). That gives you the approximation for RLL(1x) at magnification 1x.

Now we get

HL(1x) = RLL(1x) - RLC - AL

where HL(1x) denotes the needed maximum extension of your helicoid and

HR = HL(1x) - HLI is the range your helicoid has to cover when turning from infinity to 1x magnification (you can replace 1x with any wished factor of course). If HR is too long, it has to be replaced with a shorter helicoid and a tube of fixed length (say to reach only 0.5x for instance). [Example, if you would need HR = 50mm and the longest helicoid you can find is 25mm, then add a 25mm tube to reach 50mm]

I hope that was not too complicated...

Here a few images that explain that in a few images when mounting an enlarger lens (here a EL-Nikkor 3.5/63mm to a Nikon D200 camera for infinity).

[click on image to see a larger one]

First let me show how different long helicoids look like (from a astronomer shop):



Enlarger lens (with filter adapter ring to 52mm) with Leica thread mount M39 (also called LTM and is precisely M39 x 26tpi), M39-M42 adapter ring, M42 helicoid (that helicoid has Nikon mount on the rear, usually a M42-Nikon non-infinity adapter ring would have to be added):


all parts assembled (screwed into each other):


Front view (filter side):


Rear view (camera side):


Mounted on camera:


Take that indicative, it may need a much longer helicoid, if the lens has a much longer focal length, like 105mm or 135mm for instance or you don't need it for infinity but for close-up or macro shots.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Psychedelic Lilly - a UV and VIS comparison EL-Nikkor 80mm vs 105mm

Today I found a nice flower, a "Stargazer Lilly", so I thought that would be wonderful to show the beauty of that flower using the newly rediscovered use of older (chrome/black) EL-Nikkor enlarger lenses in visible light, but also in invisible UV.

All shots were done at f8, ISO400, 1/160s using Xenon flash, exposure adjusted using flash power control and ND filters. UV shots were done using the Baader-U filter.

[click on image to see a larger one]

Here now a VIS-UV differential using the EL-Nikkor 5.6/80mm:


and yes, quite a nice lens with quite good UV transmission and very little focus shift.

and here using the 5.6/105mm EL-Nikkor:


Quite more focus shift, but also quite good UV transmission.

For comparison here the VIS shot using the EL-Nikkor 5.6/80mm:


and using the 5.6/105mm EL-Nikkor:


Finally now the UV shot using the EL-Nikkor 5.6/80mm:


and using the 5.6/105mm EL-Nikkor:


So, if you look for a cheap lens, have an eye on these pretty good enlarger lenses!


P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, as me if you need an adapter ring.

[A remark on the 80mm EL-Nikkor, I tried outside and infinity tests with it and unfortunately it seems to have a prominent large UV hotspot which renders it unuseable for that...]


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Tuesday, January 25, 2011

Zeiss contest "Light is my Language" : made it to the last 10!

Well, just out of curiosity and since the title “Light is my Language” matches the intentions of my work, I submitted that photo at flickr and the Zeiss contest gallery is HERE.

[click on image to see it larger]



So I just got noticed today that it was selected as one of the last 10 for the last round. Now voting will be done by the flickr community.

I would be happy for your support by adding that photo as your flickr favorite, should you like my work!

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Sunday, January 23, 2011

[UV] EL-Nikkor 75mm for UV - old vs. new type

As I was testing (again) lenses for UV photography, I had done spectrometric tests on Nikon EL-Nikkor enlarger lenses. So now I found a new one in my lens set, so here the comparison transmission graph old metal one vs new plastic "tyre like" version. Both are f4/75mm.

[click on image to see a larger one]

UV transmission graph:



In terms of UV transmission, a neglectable difference I would say. Could that result serve as an indication that also the other EL-Nikkors in newer plastic "N" version are that close in transmission? I would be rather careful about that. Maybe, maybe not.... we'll see ;)

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Saturday, January 22, 2011

[UV] COMPONON lenses for UV

As I was testing (again) lenses for UV photography, so I ran a few more spectrometric tests now on Schneider COMPONON lenses, which might be of interest. These are thread mount enlarger lenses:

Componon (old black types) 5.6/150mm, 5.6/135mm, 5.6/105mm, Componon-S 5.6/100mm

[click on image to see a larger one]

UV transmission graph:



In terms of UV transmission, all are not great except the 135mm, which is quite different. I guess they had used a special coating for the others, but not the 135mm (transmission looks Rodagon like). All I tested have focus shift.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] RODAGON lenses for UV

As I was testing (again) lenses for UV photography, so I ran a few more spectrometric tests now on Rodenstock (now LINOS) RODAGON lenses, which might be of interest. These are thread mount enlarger lenses:

Rodagon (old "zebra" type) 5.6/150mm, 5.6/135mm, 4/80mm (newer type) and the modern 4/75mm Apo Rodagon D

[click on image to see a larger one]

UV transmission graph:



In terms of UV transmission, quite unexpected good UV transmission, surprisingly also the Apo Rodagon D type. Not having done focus shift tests, but would assume it's there.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

[UV] STEINHEIL lenses for UV

As I was testing (again) lenses for UV photography, so I ran a few more spectrometric tests now on STEINHEIL lenses, which might be of interest. These are all M42 thread mount taking lenses in silver aluminum barrel.

[click on image to see a larger one]

UV transmission graph:


In terms of UV transmission, all are quite good (except the Culminar) but all exhibit focus shift.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Tuesday, January 18, 2011

Nichia high power 4 dice NC4U133 / NC4U134 UV LED system

Here I present the newest Nichia 4 dice NC4U133 (365nm) resp. NC4U134 (385nm) based UV LED system, rated 1340mW, linear control, active fan cooled, compatible with previous versions (collimator etc.).

That should currently be the most powerful single UV LED available.

[ P.S.: I have developed 2012 a much more powerful modular UV LED system which has been shown HERE.]

[click on image to see a larger one]





Special collimators / condensors have been developed for that system.

Now that LED in action, close-up shot of the 4 dice chip at minimum power (total 4 dice, width about 4mm), using UV-Mikrotar 30mm.



A comparison NC4U133 vs NCSU033 might be interesting; the older NCSU033 shown on the right was a P7 rank (which is about 20% better than the P6 rank, which is about 20% better than the P5 rank). The gain is about a factor of 3.5 to the older P7 version (*) - quite impressive.
(*) as measured with a calibrated UV power meter; this is NOT the ratio of the peak values.


[identical intensity scales. Measurements done at full load 700mA, after 10mins of operation i.e. in hot state, this is why the peak drifts a bit to 369nm]

Currently offered UV LED torches using the Nichia chip are usually using the P5 rank chip, the factor would then be about 5x power output in favor of this solution presented here.
REMARK: If working with these strong UV sources, make sure to ALWAYS USE PROPER EYE PROTECTION! Such goggles may be had for little money, but make sure they suppress UV to at least 420nm, like for instance the SKYPER type made by UVEX (pink line). Normal glasses (rose line) and normal goggles (magenta line) DON NOT PROTECT sufficiently.




Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

A simple tutorial for reflected UV photography II

I have been asked to write down a simple "cook book style" tutorial on UV photography, which I did quite some time ago. I also wrote about the system lens + filter for UV. But meanwhile some things have changed, more research has been done, so I thought it would be time for a version II. So here it is, based on my personal experiences and likes.  [last update: 2012-09-16]

1) get a suitable lens for UV: I made a comprehensive list of lenses tested good for UV here. The EL-Nikkor enlarger lens 5.6/80mm has proven to not only have the highest UV transmission, but also is virtually free of focus shift. That and all enlarger lenses without focusing ability additionally need a focusing helicoid. Alternatively get the Novoflex Noflexar 3.5/35mm lens which also has a very high UV transmission, is virtually free of focus shift and allows close-up shots up to 1:2 (0.5x) without additional tubes or helicoids. Both lenses are ($)$$, easy to find and may be suitably mounted to achieve infinity focus. If you need a wide angle lens, that's a bit more difficult, but there are some. Still the best and the "industry and scientific standard UV lens" is the discontinued Nikon UV Nikkor 4.5/105mm, or the identical, still available from stock Tochigi Nikon UV 4.5/105mm. Also still available from stock are the JENOPTIK Coastal Optics 4/105mm UV-Micro Apo and 4/60mm UV-VIS-IR Apo Macro but those four lenses are a quite costly $$$$ investment and only fit Nikon cameras directly.

2) get a suitable filter: The 2" Baader U-filter still is the best filter you can get, better than 80% peak and 325...395nm transmission band, IR excellently suppressed, which is important for most DSLRs due to their high IR and low UV sensitivity, especially if your camera has the internal filter removed. Be prepared to expose 8-10 stops more than normal. My usual setting on an sunny to overcast day is 2...4" @ f8-11 ISO200 using a Nikon D70 or converted D200. Best is to have that filter built into a Nikon AF-1 gel filter holder, which needs a 60mm (male) - 48mm(female) and 48mm (male) - 52mm (female) step ring to mount the filter inside and also allows to mount a 52mm sunshade outside. That contraption allows to flip down the filter, adjust focus, take a VIS shot if needed for comparison studies, flip up and take a UV shot. But also screwing in and out of the UV filter works reasonably well if done with care - I do that all the time. Should you have a full spectrum converted camera (with clear filter inside), an external filter which compensates that is needed, so as to be able to shoot normal visible photos with it (as before the conversion). I recommend to use an external 2mm thick SCHOTT BG40 or SCHOTT BG39 or  Schott BG38 (in that sequence of usefulness) for that purpose and adjust white balance accordingly. Some companies offer such "compensating filters", but basically it is just the filter glass I have mentioned.

3) get a suitable UV enabled camera: My finding is that the Nikon D70(s) is the best value for money for UV as is the D40, since both work off the shelf unmodified. D80 and D200 work well either, but need the internal filter exchanged against a clear quartz glass filter first (use a professional service for that: maxmax and lifepixel in the US, Optik Makario in Germany for instance). CANON shooters - it does NOT work with Canon DSLRs, their filters and CMOS chips do not allow to record UV in an acceptable manner (see the test I have published here; extremely long exposure, high ISO, noisy results). Some Pentax, Sony , Panasonic and Olympus DSLRs also work, but all need to be converted first. Recently the Nikon D7000 has turned out to be a useful camera for UV, but needs a converting company, that can deal with the internal IR leakage caused by Nikon's IR shutter monitor (I have reported about that here in detail).

4) get a suitable UV light source: the sun is of course the best, but not always available. Xenon flashes come next as they have a very similar spectrum than the sun has. Most need the front filters removed, some even need the golden UV suppressing coating on the Xenon tube partially (leave a bit on the back or it does not ignite anymore!!) polished off (using fine Cerium oxide powder). A well known candidate is the good and cheap Vivitar 285HV flash (use 2 or 3 if needed), as it already has a clear tube and a low trigger voltage which is safe for modern DSLRs. Another one would be the stronger Nikon SB-14 hammer head flash, but here the tube needs polishing for higher UV output. Another alternative are modern UV LEDs, here especially the Nichia 365nm types. These are available nowadays built into torches, so are easy to use and not that expensive anymore. There are also more advanced systems available of course, which even use the most recent 4 dice high power UV LEDs.

5) get a sturdy tripod: you need usually at least 2...4" exposure time in full sun outside, sometimes much longer though, which calls for a sturdy setup on a tripod. UV is strongest 90 degrees to the sun where the sky is the bluest; avoid to shoot in bright midday sun, due to high IR content present (although no longer a big problem with the new Baader 2" U-Filter, but still IR leakage may happen). Using Xenon flash brings exposure time down to 1/200, but the flash need to be strong and quite close to the subject, which is not always doable.

6) get a suitable shooting habit: for comparison shots I shoot visual light first and then flip up the UV filter and shoot UV with exactly the same framing. Be careful not to move the camera. Should you be using using an older lens which most likely has focus shift, focus closer. This needs to be tested out, my finding is that the f8...f11 position on the DOF scale works best (similar to an IR mark on some lenses) but could also calibrated for that lens (like a IR mark but for UV). Shoot RAW files or high resolution JPEGs. Pro's do RAW, but for first tests JPEG will do. Set camera white balance to 2500 degrees Kelvin to avoid a blown red channel (Nikon only) or use UNI white balance.

7) get the results processed: Upload pictures to your PC and process them. They will look very red (if using Nikon DSLRs, other DSLRS produce blue or magenta looking results), but what you see is UV, depending on camera (and only if a good UV filter with no IR leakage has been used, like the Baader-U) . Then either you process them to black/white or white balance them. Then adjust to taste. UV has no "color" by definition, so you may set what you prefer. For critical pictures I use BibblePro and use its "click white" operation and the built in denoisifier. Others are more happy to use Nikon NX2.

8) get help and discuss results: exchange and discuss your results on one of the few UV forums on the net,  nikonians.com (where I am a moderator), nikoncafe.com and openphotographyforums.com. Quite a bit of my old content resides on the Nikon-only forum  nikongear.com but I am no longer contributing there.

This is in condensed form the result of some years of research and testing and of course only reflects my personal opinion - others may think differently. No warranty given or implied for all being mentioned here and you take full responsibility for all you do with that. If you need some advice or equipment, let me know, I may be able to help. I have plenty of filters, lenses etc. available, since I tested so much for the last years or may be able to direct to a source.


All my works shown here on my BLOG, my pbase.com site or my macrolenses.de site carry my copyright, so if you like to use any of my graphs or my pictures, please do ask me for my explicit permission first.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site www.pbase.com/kds315/uv_photos

Sunday, January 16, 2011

[UV] EL-Nikkor enlarger lenses for UV photography

As I was testing (again) EL-Nikkor lenses for UV photography, I ran a few more spectrometric tests on other EL-Nikkor enlarger lenses, which might be of interest. These are usually the older full metal black or chrome/black versions, not the later larger diameter plastic "tyre like" looking ones. [Here is a comparison of the newer with the older 4/75mm EL-Nikkor]

[click on image to see a larger one]

UV transmission graph for various EL-Nikkor lenses:


In terms of UV transmission, out of all tested lenses the 5.6/80mm clearly excels (reaching down to about 320nm @-3EV), closely followed by the 105mm (but which shows much more focus shift). All others have less, but still useful, UV transmission.

In terms of photography performance (focus shift for instance) see here and here and here (incl. IR). But to already state the result here, only that 5.6/80mm is nearly free of focus shift, which makes it the clear winner.

P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, as me if you need an adapter ring.


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

.

Friday, January 14, 2011

[UV] EL-Nikkor 3.5/63mm vs 5.6/80mm

Well, since we're at it, lets test the highly acclaimed EL-Nikkor 3.5/63mm (version labeled "Nikon") vs. 5.6/80mm (older black/chrome version)

[click on image to see a larger one]

Differential UV-VIS shot, left EL-Nikkor 3.5/63mm , right 5.6/80mm:


No focus correction was done during the shots using a single 400Ws adjustable Xenon flash and ND filters to balance out the exposure differences, so as to ensure an identical light direction.

Now let's compare the UV transmission of the lenses.

UV transmission graph:



The highly acclaimed EL-Nikkor 3.5/63mm loses quite obviously not only in terms of focus shift, but also due to its much lower UV transmission. Quite a surprise!

Don't get me wrong here, the 3.5/63mm is still an outstanding, very sharp lens useful for enlarging and taking. This comparison was only about UV transmission and focus shift!

P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, as me if you need an adapter ring.


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

.

[UV] EL-Nikkor 75mm - 80mm - 105mm for UV?

This is a comparison of three EL-Nikkor enlarger lenses for reflected UV photography.
The candidates are the older EL-Nikkor enlarger lenses: 4/75mm (black), 5.6/80mm, 5.6/105mm (both black/chrome)
[click on image to see a larger one]
These are UV-VIS differentials to show the possible focus shift (ghost images, white or black depending on direction of the shift:


left: 75mm, middle: 80mm, right: 105mm - identical exposure and processing for all.

And here the UV-VIS transmission graph of these three lenses.


It gets pretty obvious, that the 80mm is the clear winner, not only in terms of lack of focus shift, but also in UV transmission, since it has about double the transmission @365nm than the 75mm EL-Nikkor. No wonder actually, as the 75mm is a Tessar 4-3 design with one glued lens element, whereas the other two are double Gauss 6-4 designs.

P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M32.5 x 0.5 thread meant to fit a shutter size 0. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-010711 ).

P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, Rafcamera.com sells a suitable adapter ring.

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Thursday, January 13, 2011

[UV, IR] A surprising lens without UV + IR focus shift IV: EL-Nikkor 5.6/80mm

Well, I had mentioned that my orchids started to blossom again, so why not take a chance and try out an old friend: EL-Nikkor 5.6/80mm (the older black/chrome version)

The sequence is: UV (through Baader-U), VIS (through UV/IR Cut filter), IR (through B+W 092)

[click on image to see a larger one]



and here the same sequence but showing left and right differentials (VIS-UV, VIS-IR):



No focus correction was done during the shots using a single 400Ws adjustable Xenon flash and ND filters to balance out the exposure differences, so as to ensure an identical light direction.

And here a multispectral composite image by assigning UV->blue, VIS->green, IR->red and combining into one image without further ado.




I find that result quite interesting ... as it hardly shows focus shift, but hardly anyone seems to use it ;)

P.S.: the 80mm EL-Nikkor (the older, chrome black full metal type) has an adapter ring on its base with outer M39x26tpi screw mount (Leica enlarger mount). Beneath it is a M25 thread for older #00 shutters. Company Schneider Optics offers adapter rings, if that one should be missing (oder code 92-013251).
P.P.S.: the filter thread of that older EL-Nikkor 80mm is 34.5mm, which is pretty uncommon, as me if you need an adapter ring.


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Wednesday, January 12, 2011

[UV, IR] A surprising lens without UV + IR focus shift III

Well, my orchids started to blossom again, so why not take a chance and try one of those lenses out I published about a while ago here.

The sequence is: UV (through Baader-U), VIS (through UV/IR Cut filter), IR (through B+W 092)

[click on image to see a larger one]



and here the same sequence but showing left and right differentials (VIS-UV, VIS, VIS-IR):



No focus correction was done during the shots using a single 400Ws adjustable power Xenon flash and ND filters to balance out the exposure differences, so as to ensure an identical light direction.

And here a multispectral composite image by assigning UV->blue, VIS->green, IR->red and combining into one image without further ado.




I find that result quite interesting due to the very small focus shift this lens shows for UV and IR as compared to the visible shot. To prove that, I made a shot under the same conditions of above of my calipher (this is a differential center cut out shown UV-VIS, VIS, IR-VIS):


Which shows, that for UV there was only a 0.2mm and for IR a 0.4mm focus shift (but in opposite direction).


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Tuesday, January 11, 2011

Micro-Nikkor 105mm for UV photography?

Well, today have a look with me what the normal well known Micro-Nikkor f4/105mm lens transmits if used for reflected UV photography. I measured the transmission in my spectrometer without (rosé) and with Baader-U filter (pink line). Also shown is the comparison to using the "standard lens" for UV photography, the UV-Nikkor 105mm with Baader-U filter (purple line).

[click on image to see a larger one]




The Micro-Nikkor 105mm with Baader-U filter showed a transmission which was limited to the 354 - 393nm band with a peak at 375nm (about 18% or about - 2.5EV compared to using the UV-Nikkor).

So it obviously does pass some limited, but useful amounts of longer UV, but that would still be enough to show the typical UV flower patterns, as these show in the 370-420nm band from my experience. A normal exposure using an UV-Nikkor 105mm is around 2-4sec at ISO200 f8-11, so expect exposure times of 8-16sec or open up the aperture a bit more and/or raise ISO to 400.

Further you have to deal with focus shift that Micro-Nikkor has if used for UV, but that may be dealt with using my calibration technique, shown here on my BLOG.

In case you wonder what a camera sensor might be able to record and in which channels of that transmitted UV through lens and filter, have a look at this link here which shows the result of a scientific study a colleague of mine has conducted and published using a Nikon D80 camera (same sensor than the Nikon D200) which had its internal filter removed.


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Friday, January 7, 2011

Carl Zeiss Jena "Spy" lenses for VIS + IR

Well, many years ago in times of the cold war, Zeiss Jena had to developed special lenses for a very special ministry of the former east German GDR (dig you guess which one I mean - STASI, also called MfS), which are hardly known to the public, but are available. These are corrected for focusing in visible light, but also for shooting in (deeper) invisible NIR. There were also special noiseless cameras (GSK also called SR899) developed for these lenses.

To make things clear, I distance myself from that former purpose, but am interested in the performance of those special lenses!

The lenses were designed in such a way that the aperture location (more precisie the entrance pupil) was in front of the lenses, which allowed taking photos through small holes in walls, through button holes in bags etc. - I guess the purpose gets clearer now. A set of fixed apertures and also a variable iris usually comes which each lens. All these lenses cover the full 24x36mm format.

I was able to get a set of these very special lenses thanks to the contact to and the efforts of Detlev Vreisleben, a german engineer who, after his retirement has concentrated to shed some light onto these.

Here a list of these lenses (SO = "Spezial Objektiv"):

- SO-3.1 f2,8/35mm a FLEKTOGON wide angle
- SO-3.2 f2,8/50mm a BIOTAR normal angle
- SO-3.3 f3,5/75mm a TESSAR short tele
- SO-3.4 f3,5/135mm a SONNAR tele lens

They have a special M36 camera thread mount, but are easily adaptable.

First tests have shown very good to excellent sharpness in VIS as well as NIR. More about that later...

[click on image to see a larger one]



And no, they don't transmit UV at all, since designed for the other end of the spectrum incl. the special NIR coating.

Transmission graph:


(The 75mm Tessar is missing in that graph; two further lenses are included for the HFK "half format" camera)

Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Tuesday, January 4, 2011

Wide angle lenses for UV?

Here today a wide angle test I made with some wide angles I had around (all Nikon mount except the Lithagon)

1) Nikkor E 2.8/28mm
2) Nikkor-H 3.5/28mm
3) Tokina RMC 2.8/28mm
4) Tokina RMC 2.8/24mm
5) Enna Lithagon 3.5/28mm
6) Noflexar 3.5/35mm

The green vertical line indicates the 365nm wavelength and in that box one can find the transmission at 365nm as the rightmost value. Remember that 12.5% equals -3EV, 25% equals -2EV, 50% eq. -1EV

The 24mm lens is used to show how harder it is to get some useful UV transmission when the focal length and complexity of the lens design increases.

The blue line indicates the transmission of a typical Noflexar 35mm for comparison, about 63% at 365nm. A very good lens for UV which hardly shows any focus shift!

[click on image to see a larger one]


Remark: this test only shows the transmission of a lens, it does not say anything about sharpness, contrast, flare resistance, freedom of hotspots etc. which has to be evaluated additionally through photographic tests before a lens may turn out useful for UV photography!

[P.S.: that green line (Lithagon 28mm) shows the typical effect of "lens yellowing" which results in some loss in transmission of shorter wavelengths]


Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos

Sunday, January 2, 2011

Phalaenopsis stereo in ultraviolet and butterfly vision

Today the first post of year 2011 will be about shooting stereo images (for crossed eye viewing) of a Phalaenopsis hybride orchid flower in visible, ultraviolet and simulated butterfly vision using a special stereo setup I'm currently investigating.

[click on image to see a larger one]

VIS (normal human vision image 400-700nm using UV/IR cut filter):


UV (ultraviolet image 300-400nm using Baader-U filter):


BV (simulated butterfly vision image 300-700nm using my XBV2 filter):



Stay tuned, more will follow on that fascinating subject...

More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos