Question for the film guys.

[David Kennett]

What is the shutter speed (or speeds) on pro film cameras? I've seen all the suggestions to use slower shutter speeds for JVC HD1-10. Now HD100 has method of interpolating two 60p frames to make 30p frame. It seems like this would do pretty much the same as long exposure. Are there ever any circumstances where a high shutter speed would be used for 24 frame film?

Thanks all! Maybe this is why film folk have been satisfied with 24. I'm just an old TV guy.

[Richard Alvarez]

The higher shutter speeds in regular cinematography, are currently being used a lot for 'action' sequences. Saving Private Ryan, Gladiator, the recent Kingdom of Heaven made extensive use of the higher shutter speeds (Read that - smaller shutter angle) for 24fps. It gives that harsh, almost stroboscopic feel, without actually changing the 'speed' of the film. Of course, it takes increased lighting/faster lenses.

[Charles Papert]

For 24 frame cinematography, a 180 degree shutter is standard (half of a circular disc admits light during a 360 rotation per frame). This translates to a 1/48th second exposure time (comparable to the shutter speed setting). If one was to shoot at 48 fps with the same 180 degree shutter, you would now see an effective 1/96th second exposure. Closing down the shutter to 90 degrees will also result in a 1/96th second exposure. As Richard points out, this look was popularized by those two films and is seen often in music videos and commercials. The recent Old Navy ad with the four girls dancing on the docks is another good example of a skinny shutter, probably 45 degrees from the looks of it.

[David Kennett]

Thanks,

I guess that really shows the need to use slower shutter speeds for 720p30 - at least for most things. I guess one chooses film sensitivity to match the situation. This brings up another question. Can the shutter be open for more than 180 degrees? It obviously takes time to advance the film.

[Heath McKnight]

Whenever I shoot anything for a movie, I use a 1/60 shutter, be it with 24p or 60i (or even 30p).

heath

[Richard Alvarez]

David,

"Depends on the camera" is the answer for shutter angles greater than 180 degrees. Back in the 'super8' days, a 'low light' super8 camera, had 210 degree shutters. Only very expensive ones even had variable shutters.

My old bolex had a vairable shutter, but I don't think it was greater than about 190... (long since gone). The Mitchel BNCR we shot "After Twilight" on, had a variable, but again, I don't think it was greater than 210. Charles can speak to the more modern cameras. I'd bet they do.

[Charles Papert]

Most cameras have 180 degree maximum shutters. Some are mechanically adjustable down to 22 or 11 degrees (you have to physically crank the leaves of the shutter closed), others are electronically adjusted with motors. The latter allows you to do speed/shutter ramps, which means that you can program the camera to ramp up to high speed and it wil automatically adjust the shutter to maintain constant exposure (this is how you do a shot that starts at regular speed and smoothly shifts into slow motion with a film camera).

[Barry Green]

Originally Posted by David Kennett

Can the shutter be open for more than 180 degrees? It obviously takes time to advance the film.

Panavision NZ has a list of most modern film cameras, and their shutter angles, at http://www.panavision.co.nz/main/kba...ecamglance.asp

Although some Super8 cameras had 220-degree shutters, it looks like the most-open you'll find on most modern cameras is about 200 degrees. And while I know that it's popular to say that a film camera has a 180-degree shutter, a quick glance through that table will show that none of those cameras have a fixed shutter at 180 degrees -- they're either adjustable, or they're fixed at 170 or 172.8 degrees (and earlier cameras used 144 or 150 or 156 degrees, as well). 180 degrees is a popular setting, sure, but 172.8 or 144 or 200 degrees will still deliver the "film look".