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...

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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

Aster hybride meets Noflexar 35mm lens

Today few shots of an Aster hybride using the Noflexar 3.5/35mm lens and various filters.
No noticeable patterns, as expected though.

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visible light shot: 


UV shot (using Baader U-filter and Xenon flash): 


Butterfly vision shot (using my XBV2 filter): 


UV induced visible flourescence shot (using Baader UV/IR Cut filter and Nichia 365nm UV light): 


As boring as it might look like, this now is quite interesting (to me) as it shows UV induced IR fluorescence. Lights were all Nichia UV LED sources I could get hold of (to make sure not a bit of IR would be present), a B+W 092 cut filter (>65nm) in front of the lens and 30sec exposure in total darkness:
 


With the naked (but UV protected!!) eye quite a bit deep red fluorescence gets visible, but hard to ban that on a photo....

Same experiment but using a dark orange filter and same UV lighting setup in darkness (Nichia 4x 365nm LED using a front attached Baader U-filter to block any visible light!):



I have now found a reliable method to professionally infinity convert Noflexar 35mm lenses to Nikon mount - ask me if you need one!

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

Gaillardia "Summerwind"

Well, I found a previously unknown (to me), pure yellow species of Gaillardia. Since that type of flower showed so many surprising aspects, I wanted to see what this new one hides from the human eye....

[click on image yields a larger one]

This now is the visual appearance as we humans are used to see:



The tetrachromatic image ("butterfly" shot) (UV+B+G+R) using XBV2 filter:



The trichromatic image ("bee vision" shot) (UV+B+G) using XBV2 filter:



This is the UV induced fluorescence shot using XCUT2 filter:



and this the reflected UV shot using XUVIR filter:



Well, also that flower shows some surprising properties ...

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

Bidens ferulifolia, various filters + light sources

Well, another nice target for UV photographic experiments is Bidens ferulifolia, the variety "Peters's Surprise".

Equipment used was: Nikon D70 (unmodified), ISO400, f5.6-8, 1/160sec, old 100mm enlarger lens.

[click on image to see a larger one]

VIS using XCUT2 filter (400-650nm):


UV using Baader U-filter (310-390nm) - synthetic DOF:


XUVIR multispectral filter (300-1000nm), UV Flash:


UV induced fluorescence using XCUT2 filter (400-650nm), UV flash:

So, as you may see, a variety of results also that flower shows us.

P.S.: if you wonder what "synthetic DOF" means, I used "stacking" to increase the DOF artificially.

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 multispectral example using Mexican Zinnia

Just a few quick shots today using the UV Rodagon 60mm for multispectral analysis in visual light, UV, UV fluorescence and IR. As usual I used a Nikon D70, SB-140 flash w. SW-5UV filter, UV Rodagon 60mm, Baader 2" U- and UV/IR Cut- filter (for UV and UV fluorescence), B+W 092 filter (for IR).

Target was a Mexican Zinna; the little flower head is about 12mm in diameter, i.e. magnification was about 0.5x which still is within the 
design range of that lens. Here now the visual shot:




The UV shot reveals that special pattern this flower shows:




UV fluorescence shows the intensive light of the pollen:




IR finally looks quite transparent:




Quite interesting how the very same flower appears in different wavebands!

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>