Test Pentax SMC f1.8/85mm vs. Ultra Achromatic Takumar f4.5/85mm

Here a quick test, Pentax SMC Takumar 1.8/85mm vs Ultra Achromatic Takumar 4.5/85mm to see how that might perform. That SMC lens is said to be the sharpest Pentax ever made for that focal length.

You'll find left the SMC, right the UAT 85mm. [click on image to see a larger one]

1) Cushion on my balcony, shot at f8.

full format:


100% detail:




2) Plantane trees about 5 meters from my balcony, shot fully open (different DOF due to f1.8 vs f4.5)

full format:


100% detail:


The UAT behaves not too bad considering, but already the SMC outshines it ....

At (nearly) infinity, it starts to look different though since the UAT was designed for close work - tile roof ca 25 meters away, my "standard test" object, shot also at f8

full format:


100% details:

that latter one I usually use to determine the amount of CA on teh black white transitions.

 
Well, here at about infinity, the UAT clearly looses in terms of sharpness and contrast against the SMC 85mm lens!

But bear in mind, the UAT was made to record from 220nm to ca 1100nm without CA (UV to NIR) i.e. without focus shift and for that it keeps up with its rival excellently (which only does visible light)!!


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

Nikon D80 / D200 spectral response UV IR

This time a technically oriented entry, about the spectral sensitivity of a (modified) Nikon D80 camera. This camera uses actually the same 10Mp CCD sensor chip as the Nikon D200, so the results should be transferrable to the D200 also. The camera has been modified by removing the internal filter, so the response is that of the bare sensor. This is a result of the work and has been made available through Dr Geert Verhoeven, Uni Ghent who works on aerial UV + IR archaelogy and with whom I have the pleasure to co-operate on this subject. I'm greatful for his permission to publish this result here.

[click on image to see a larger one]

Spectral response (valid for about 380-850nm) - (c) Dr G Verhoeven:

[Please note that the valid range of the results is about 380-850nm only, since outside that range, the equipment used was not suitable and the measurement errors too high.]

It gets quite obvious, that this camera has some useful UV response in the red channel and only minimal response in the green and blue channels.

For near IR (NIR) however it shows quite high response in the red but also green (>750nm) and blue (>780nm) channels.

[this is a excerpt from:

Journal of Archaeological Science Ref: JASC08-363R1
Title: An Attempt to Push Back Frontiers - Digital Near-UltraViolet Aerial Archaeology
Authors: Geert Julien Joanna Verhoeven, Ph.D.; Klaus D Schmitt, Dr.-Ing.

]

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

Rudbeckia Meadow - Human, Butterfly, Bee vision

A Rudbeckia meadow in full bloom, human, butterfly (tetrachromatic) and bee (trichromatic) vision shot using my one-shot XBV2 filter.

[click on image to see a larger one]

Human vision:



Simulated Butterfly vision:



Simulated Bee vision:




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

BBC new series "Invible Worlds" incl. Bee, Bird, Butterfly etc. vision

Well, I have been granted permission to mention it: BBC London has asked me to contribute my work of the invisible to their new three part science series "Invisible Worlds" which will be on air in spring 2010. The first part of the series will be about the natural world and things we humans cannot see, but other species can, like bees, birds, butterflies, spiders etc. because it may be in a spectral area not accessible to our eyes or other senses, but to them.

That was quite a challenge, to transfer my special still life photographic technique into the world of HDTV film, but after some weeks of intensive work especially on filtering and lighting, I found working solutions to that.

We filmed it in HDTV end of July in the UK in their studio and an outside location, using my special lenses + filters I have developed, to show (simulated) how bees, butterflies, birds etc. may see the world in comparision to how we do see it.

Results of that work I cannot show yet, but if you have a look at my recent works presented in my UV BLOG here, you may get a glimpse what it will be about...

Once the digital edit and cut has been done and the air date will be available, I will notice it here for those who have access to their BBC1 Science programme!

This is from some prep work I have done before, wide angle shot of Rudbeckia fulgida between red Echinaceas and prairie grass [click on image to see a larger one]:



Here more current info on Richard Hammond's Invisible Worlds at BBC1!

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 ferulifola - simulated insect point of view

This is, again, about Bidens ferulifola shown in simulated tetrachromatic vision. But this time the point of view of an insect is being shown, using a very special wide angle lens capable of transmitting ultraviolet light.

[click on image to see a larger one]



Also here in this simulated tetrachromatic vision image that special UV pattern is shown, but also that wide angle view an insect has.

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

Rudbeckia missouriensis - simulated tri- and tetrachromatic vision

Today from my evolving Rudbeckia series a Rudbeckia missouriensis flower portrait in simulated trichromatic and tetrachromatic vision. Birds and butterflies are Tetrachromats, so are able to see UV, blue, green and red, wheras we and bees are trichomats; we see blue, green and red, bees however see UV, blue and green. This is what I have tried here to simulate using specilized filtering techniques.

[click on image to see a larger one]

Simulated tetrachromatic vision (i.e. UV=blue, Blue, Green, Red):



Simulated trichromatic vision (i.e. UV=blue, Blue, Green):



For comparison, this is the normal, human vision version (i.e. Blue, Green, Red):



and here also the pure UV (300-400nm) response showing that prominent UV pattern:



Also here for that flower both simulated tri- and tetrachromatic vision images include that UV pattern plus also the other channels bees (trichromatic) resp. birds/butterflies (tetrachromatic) can see.

And in situ shot example of this flower is HERE

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

Rudbeckia triloba in simulated tri- and tetrachromatic vision

Today a Rudbeckia triloba flower portrait in simulated tri- and tetrachromatic vision. 

[click on image to see a larger one]

Simulated tetrachromatic vision (i.e. UV=blue, Blue, Green, Red):



Silmulated trichromatic vision (i.e. UV=blue, Blue, Green):



For comparison, this is the normal, human vision version (i.e. Blue, Green, Red):



and here also the pure UV (300-400nm) response showing that prominent pattern:



Well it gets quite clear, that both simulated tri- and tetrachromatic vision images include that UV pattern, plus also the other channels bees (trichromatic) resp. birds/butterflies (tetrachromatic) can 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