The Panavision 200 Degree Shutter

[Peter Abraham]

Please regard the photo embedded below. This is a common enough image. Back in the day, the Panavision PSR ( and perhaps other very early Panavision bodies ) had a magazine cover. It looked just like this. Many of the images I see include the information that reads, " R=200º ".

 

It seems to me that all camera bodies go out the door ( or, went out the door ) with a 180º shutter unless specifically altered for a shot or project. Note that this information is a part of the molded side of the Magazine barney and not a strip of tape, etc.

 

Why would the early Panavision bodies have a 200º shutter angle as a default when either a Maltese Cross type ( 90º x 2 ) or a 180º shutter was the standard? And how would this different shutter angle be resolved when projecting prints in a projector that used a Maltese Cross shutter?

 

Best to all,

 

Peter Abraham, S.O.C.

[Eric Fletcher S.O.C.]

Because those cameras had 200degree shutters

[William Demeritt]

Didn't the advent of the 200º shutter come with the "bowtie" style mirror that offered more exposure (something the film stocks desperately needed/wanted)? I believe the reflex system was actually two 80º mirrors. The film itself still moved through the gate at 24 frames per second, but the exposure time changed from 1/48 of a second to 1/43 of a second (a change of 23/10000 of a second), and the pulldown claw moved the exposed frame out and set the next position for the registration pin in less time. Rather than taking 1/48 of a second to move and set, it should take place in 1/53 of a second.

 

So, if the spinning mirror went from 180º to 200º, the movement would compensate for the longer exposure (or else each frame would smear for 23/10000 of a second, and leave a gnarly ghost)? And if it was <180º, then the spinning mirror would simply spin faster, limiting exposure time of the individual frame but keeping the frames progressing thru the gate at 24fps.

 

I would imagine that projection would take place as normal, since despite all the exposure trickery of the mirror and movement, the film was still shot at 24 frames per second. If the film is projected at 24 frames per second, all the extra effort should be seemless to the audience and enjoyed by a DP getting 11.05769% extra exposure out of his stock.

 

Anyway, all conjecture. I interned at Panavision Florida a while back, and remember learning about that stuff. I think all the Panaflex cameras could do 200º shutters either by turning a little wheel to the position of the angle you wanted.

 

sup?

[Peter Abraham]

Thanks Wil. Excellent. It's the first 35mm body I learned to thread. I remember the km no , but not the reason!!!

[chris bangma]

On Panavision cameras the mirror and the shutter are separate. They are both tied together and always run at the same speed in reference to each other.