Panascope 16

The magic number is 3.81

 

The distance of two corresponding edges of the sprocket holes of double eight film is 3.81 mm. Since the distance of the sprocket holes at 16 mm film is 7.62 mm there has to be a special film transport to get half the height of the normal 16 mm picture. To get a clear view on this technical issue I made the above model of how I thought an intermittent movement for a Panascope 16 camera might work. The only solution I could think of are two claws of the simple oscillating type (the German expression is Schleppgreifer). In contrast to elaborate D-curve claw intermittent mechanisms that are also used in projectors the simple oscillating claw works in form of a ratchet. A spring loaded edge snaps into the sprocket hole and moves the film until it turns into the other direction and disengages its connection to the film. On the backward movement the spring loaded edge simply slides on the film surface between the sprocket holes. This is the reason why this principle can’t be used in projectors as the film would be damaged after a few screenings. This problem does not apply with cameras of course. The whole idea is to have two claws in a distance of the sprocket hole interval of double eight film or in a distance which is an uneven multiple of this interval. If the two claws are 3.81 millimetres away from each other they will work on the same sprocket hole, when they are further away they will work on different sprocket holes.

 

Converting a camera to feature this Panascope 16 film format is not easy. Identical to Panascope 8 there are two possibilities: Using an existing 16 mm camera seems to be logic but causes a lot of troubles. Not only that you have to install a second claw but also the film transport by the sprocket wheels has to be reduced by a half. This requires an immense intervention into the gear mechanism of the camera. The other way would be to convert a double eight camera. This would have the advantage that most of these cameras do not have sprocket wheels so there is no change necessary at this point. On the other hand a massive intervention has to be carried out to install a mount for 16 mm lenses. So both ways have their huge disadvantages.

 

Falling back on the experiences I made with a conversion of an Admira 16 to Panascope 8 I tried the a conversion of the same model to Panascope 16. The result is not perfect yet but promising. More about this camera soon...

panascope 16 kromavision

After two weeks of adjustment work I managed to get absolutely even spaces between the frames (constant frame lines). This is essential for a steady picture. The calibrated millimetre scale shows the distance of the sprocket holes (7.62 mm), the width of the frame (11.1 mm) and the height of the frame (3.7 mm)

Just a few words on the panoramic format. The usable picture size is 3.7 by 11.1 millimetres. This gives an aspect ratio of exactly 1:3.0. Some of you might say why not widening the gate a bit further into the sound track? First I don't think that an even wider picture would look good and second at a certain point it would be necessary to recenter the lens. And this is a work I would not like to do on purpose. A third reason for ristricting myself to this frame size is that it still allows using c-mount lenses that are conceived for a 2/3 inch sensor size. It is possible to get focal lengths of 8 or even 6 mm for affordable prices.



I take liberty of calling this 3.7 by 11.1 format KROMAVISION.   😊


Panascope 16 Kromavision 1:3

After a friend of mine gave me some Bolex spare parts I had the chance to experiment a bit with this type of camera. I really managed to convert the transport mechanism of such a Bolex to feature Panascope 16. The steadiness of the picture is as good as with the usual Bolex. Since my camera is not a Reflex model it allows using many C-mount lenses; even some types made for CCTV cameras.

Bolex Panascope 16
Panascope 16 Kromavision

I decided to make a new shutter blade with a smaller opening of 120 degrees instead of the original 190 degrees. 120 degrees means that you have to multiply the frame rate by 3 to get the exposure time. So 18 frames per second give a 1/54 of a second (≈ 1/60 s) shutter time. This results in sharper images because of less camera shake. Second the camera is better adapted to today's highly light sensitive films – the lowest ISO of colour film is 50 ASA/18 DIN, which would have been rated highly sensitive when this Bolex was made in the late 1950s. In full sunlight and at 18 fps you don't have to stop down more than f/11 with such a film. Stopping down further increases the danger of diffraction short focal length are prone to.

Panascope Bolex

Now I have to build myself a scanner for this special film format. I will use the transport mechanism I made for the initial testing of this principle. Here is an update showing the current intermediate stage.

Panascope 16 Telecine
Panascope 16 scanner

The scanner is finished now. It just needs a more precise adjustment of the two claws for better stability of the two frames within the (usal) frame of 16 mm. Beyond that I made an universal power supply that can be used for upcoming scanners. ;)

Marco Kröger M.A. 2020


last revision 12. October 2020