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Author
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Topic: anamorphotic lens question
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Joerg Polzfusz
Jedi Master Film Handler
Posts: 815
From: Berlin, Germany, Europe, Earth, Solar System
Registered: Apr 2006
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posted June 28, 2006 07:01 AM
Hi,
yesterday I was trying whether my Iscomorphot 8/1.5x can be used for projecting (in combination with my Bauer T610) or not... It was working, but with the anamorphot the picture is only half as bright as without. I think this is very strange since when putting the Isco in front of a camera, the picture is nearly as bright as before. (The Isco is so small that it only fits my Fujica P2 which hasn't got TTL-exposure, but other Iscos do have a lightloss of 1/3 f-stop.)
Why is this?
Some guesses:
1) When using the Isco in front of a camera the eye somehow gets tricked - the lightloss is always the same.
2) When using the Isco in front of a camera the light of 1.5 frames gets bundled onto a single frame. Hence the lightloss is less than compared to projecting (since then the projector's light for a single frame has to enlight 1.5 frames).
3) Same as 2, but with an additional factor: the distance between projector's lens and Isco is too large (can't get below 2cm, while it's only 3-4mm on my Fujica P2), hence there's some additional lightloss due to reflectations, ... .
Does any of the above makes sense? Or is there another cause?
Jörg
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John Whittle
Jedi Master Film Handler
Posts: 791
From: Northridge, CA USA
Registered: Jun 2003
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posted June 29, 2006 11:07 PM
The two most common are the Sankor 16D and the Kowa 16H (which is the same as the 8Z). These optics appear with many different engravings on them (Elmo, Eiki, Victor, Singer, etc).
The problem is you really need to test the lens since any slight misalignment of the front and back optics kills contrast of the image (you'll notice when you focus a scope lens, the elements don't turn).
To use a lens for photography, remember that you'll have to focus both the prime (back lens) AND the scope lens. Professional lenses (i. e. Panavision & Arriflex et al) have a single focusing ring that does both sets of elements at once.
You can get acceptable results, but restrain youself from zooming during a shot since you might notice some lens imperfections in the shot.
There are also some German lense with a 52mm barrel, but they're fewer and generally sell for more money. But in any case test the lens before you buy (or get a money back guarantee) since the lenses can go out of alignment over time with rough handling.
John
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Joerg Polzfusz
Jedi Master Film Handler
Posts: 815
From: Berlin, Germany, Europe, Earth, Solar System
Registered: Apr 2006
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posted June 30, 2006 05:06 AM
Some specifications of 2x anamorphots with a 52mm rear (collected by Martin W. Baumgarten):
1. KOWA 16-H (or 8-Z) lens
* Magnification (horizontal).....2x
* Distance Scale.................5ft to Infinity
* Rear Barrel Diameter...........52mm
* Length.........................84mm
* Net Weight.....................530 grams
* Filter thread..................none (must use add on Centafit {72mm} or similar)
* Rear Barrel Threading..........50mm
* Light-loss Absorbtion..........1/3 F-Stop or less
2. ISCO CENTAVISION (sold by Widescreen Centre in England and Scoptimax in Germany)
* Magnification (horizontal).....2x
* Distance Scale.................5ft to infinity
* Rear Barrel Diameter...........52mm
* Length.........................87mm (at infinity setting, 81mm at 5ft setting)
* Net Weight.....................520 grams
* Filter Thread..................72mm
* Rear Barrel Threading..........49mm
* Light-loss Absorbtion..........1/3 Stop or less
3. SANKOR 16D (aka JAN 16-D)
* Magnification (horizontal).....2x
* Distance Scale.................5ft to infinity
* Front outside diameter.........74mm
* Rear Barrel Diameter...........52mm
* Length.........................129mm (at Infinity setting)
* Net Weight.....................700 grams
* Filter Thread..................none
* Rear Barrel Threading..........52mm(?)
* Light-loss Absorbtion..........1/3 Stop or less
There's also a "Kowa 16-F" that's similar to the "Kowa 16-H", but longer at infinity (hence vignetting will be worse than onthe 16-H). (Using the "Kowa 16-H", you won't be able to use the zoom-range below 15mm or 20mm, depending on the camera.)
There's also a "Bell & Howell" anamorphot made by Kowa with a rear-barrel with a 54mm-filter-thread (There are cheap 52mm-to-54mm-step-up-rings!). It's a slightly modified version of either "Kowa 16-F" or "Kowa 16-H".
BTW: FFR-Film is selling a "CS Adapterring" to mount a Kowa 16-H/8-Z to any lens with a M52, M55 or M58-filter-thread for 45EUR:
http://www.ffr-film.de/Katalog/Seiten/Anamorphotenhalter.htm
Of course this will only be of help when your super8-camera's filter thread doesn't rotate while zooming/focusing.
Jörg
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