Rodenstock TV-Heligon

[mkleywegt]

And finally the package has arrived.
got 'em for virtually nothing, though the add was very undetailed.

3x bulky Rodenstock TV-heligon f=50mm w/ fixed iris. no value mentioned, but they behave damn fast.
Anyone ever seen this lens before?any idea about aperture size? (it's the lens on the right so guess not a 1:0.75, foto from the net)


Immediately i fell in love with the industrial look. and mounted to m42. Did some first test shots yesterday.

Very hard to focus indeed and so not perfect foto's (handheld w/windy and not very sunny conditions). but i really love the bokeh... uch... out of focus effect. Also the focus point from the front lens element seems to be quite usable (app. 15cm)




What's the strange blueish effect on the last pic? (noticable on all pics with a lot of black)



on my ccd c-mount video camera it was possible to mount the lens much closer to the pickup sensor (app 5mm) which resulted in way sharper image and a focus point of app. 27cm from the front lens element. unfortunately i'm not able to take snapshots at the moment (interline transfer ccd, app. half a megapixel...)

(ps, if someone is interested i'd like to swap 2 for someting similar, as they're all 3 similar)

[LucisPictor]

Dreamy!

The blue edges most probably are chromatic aberration on high contrast edges wide open.

[Orio]

I would call it a CA festival it even splits rays like prism.
I used to have this effect when mounting my videocamera wide additional on reflex lenses.

[piticu]

[kds315*]

Split in channels and you see why.

visual
blue
green
red

So you would usually focus on the green channel due to our eye which has the highest sensitivity around 540nm. These lenses have a very different focus for red and blue.

[piticu]

[kds315*]

What I meant is that you focus on green (in a visible light picture) ANYWAY since this is the max sensitivity. You do it without knowing.
The outcome is what I showed.

[Ballu]

These lenses are really designed for Green sensitivity. Usually use to capture X-Ray results for video streaming. After X-rays passes through the subject, to make the result visual to human eyes, hits some green chemical. (I forgot the name of the chemical). That green light is captured by these "really" fast lenses (as the the light emitted by chemical is very low in intensity).

I have 2 of these type of lenses... love those. And I think Rod 68/1.0 can do focussing to few feets on rangefinder (doing to 1.5 feet on Canon DSLR). I am hoping, I will be able to use these lenses for "funny" portraits with new mirror less cameras (micro 4/3 format)

[kds315*]

Phosphor / phosphoric is the "chemical substance".

Came (actually comes since some are still used) in different compositions i.e. usally doped with some rare earth elements which decided on color (= emission wavelength, from UV, over green to yellow and orange etc) and phosphorescence (= afterglow effect, which could be the same but also a very different color).

Here some spectra of recent phosphors:

http://lite.bu.edu/lite1/spectroscopy/spectra.html

and here a pretty neat article on phosphors:

http://www.answers.com/topic/phosphor

[patrickh]

Klaus
You consistently amaze





patrickh

[kds315*]

...and why would that be so???