question

Mickey Kafka · April 21, 2009

If shooting one frame at a time on the Bolex, what is the shutter speed?

Tom Jensen · April 21, 2009

If shooting one frame at a time on the Bolex, what is the shutter speed?

I'll probably get this wrong but 1 frame per second with a 190 degree shutter is 1 x 360 which is 360 divided by the the shutter angle which is 190. That equals 1.89 which is slightly under 2 and you put one over that so it is just under 1/2 second.

Adrian Sierkowski · April 21, 2009

There is a mode on the Bolex, whose name i currently forget, where it snaps the shutter at the same speed as though it was filming 24fps. I think it's the "P" as opposed to the "M" though I may have that reversed. Looking in.. though.. on the shutter opening will show which is which...

Bear in mind.. it has been awhile since I worked with a bolex and am forgetting most things....

edit:

found this

http://74.125.47.132/search?q=cache:fWLqSK...=clnk&gl=us

Tom Jensen · April 21, 2009

There is a mode on the Bolex, whose name i currently forget, where it snaps the shutter at the same speed as though it was filming 24fps. I think it's the "P" as opposed to the "M" though I may have that reversed. Looking in.. though.. on the shutter opening will show which is which...
Bear in mind.. it has been awhile since I worked with a bolex and am forgetting most things....

edit:

found this

http://74.125.47.132/search?q=cache:fWLqSK...=clnk&gl=us

Bolex's are great. I picked up one at a garage sale about 20 years ago. It the parallax viewing system on the side and a 10mm Switar lens. The images were beautiful. Just crank it up and let it rip. Someone on here posted the surfing footage and It reminded me of what little equipment you can use and still get great images.

Adrian Sierkowski · April 21, 2009

Oh i certainly loved the camera. In fact, when I was shooting the doco in Senegal as soon as I touched down, I though; man I'd would have been incredibly smart to bring a bolex out here with some 50D.... I'm sure the film would've survived and when the power did go out (for 2 days on and off so nothing charged) we could've still shot w/o the need for batteries. OH well... next time...

Mickey Kafka · April 21, 2009

I'll probably get this wrong but 1 frame per second with a 190 degree shutter is 1 x 360 which is 360 divided by the the shutter angle which is 190. That equals 1.89 which is slightly under 2 and you put one over that so it is just under 1/2 second.

Okay, I was getting 1/2 second too, I just wanted to make sure. Thanks! Right now we're using both Bolexes and Arriflexes, both are impressive.

Mickey Kafka · May 4, 2009

Great, thanks that helped a lot! :)

Simon Wyss · May 6, 2009

That depends

1 on the model in use, i. e. whether it's a pre-1954 Bolex with the 192 degrees shutter or a later with the 170 degrees shutter or a reflex one with the variable 144 degrees shutter,

2 on the speed set with the governor knob (which should be on 48 or more),

3 on the shape in which the camera is (lubrication, ambient temperature), and

4 on how you move the mechanism (and film), either by the built-in spring or by an electric motor.

Each time the mechanism is released the governor is sped up to almost full torque but not fully. It's barely possible that a spring driven movie film camera reaches full speed within one cycle, so the first frame actually is always a little overexposed. This in turn does not harm frame-by-frame work since all single frames will be exposed with the same error.

The governot set at 48 fps or more you'll have around 1/40th second with a 170 degrees shutter of an average camera. Some springs, though, may have become a little lame . . .

Edited May 6, 2009 by Simon Wyss