Shutter Angle

Dominik Muench · February 4, 2005

Hi everyone,

i started of shooting with an arri sr2 and recently shot my first shortfilm with an aaton xtr super 16 (seeeexy camera;), this is the first camera i worked with that had the option of varying the shutterspeed, i know this is a bit embarassing to ask in my position, but what are the reasons to have a different shutter angle than the standar 180 or 172 degrees ?

thanks for your help

Alvin Pingol · February 4, 2005

For artistic effect (motion blur), to sync to a refreshing light source or monitor (e.g. fluorescent lights, computer monitor, TV, etc), or alter exposure, though exposure is usually done via aperture changes or with ND filters, as changes in the shutter angle can give you that artistic effect you may not want.

Dominik Muench · February 4, 2005

For artistic effect (motion blur), to sync to a refreshing light source or monitor (e.g. fluorescent lights, computer monitor, TV, etc), or alter exposure, though exposure is usually done via aperture changes or with ND filters, as changes in the shutter angle can give you that artistic effect you may not want.

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ah ok, so would it be possible to get a sharper and crisper image with a different shutter angle ? and how does that change my exposure for example lets say i change my angle to 90 degrees, how do i determine exposure then ?

Nathan Milford · February 4, 2005

172.8 degrees makes the shutter speed 1/50th of a second at 24fps. This allows you to film 24fps in countries with a 50hz power system and also shoot PAL monitors with a minimized rollbar.

90 degrees essentially halves the amount of light hitting the film (90 is half of 180) so you will need to open up a stop. Essentially it will decrease motion blur and motion will seem less smooth.

The XTRprod with an 11-position shutter can go all the way down to 15 degrees.

Adam Frisch FSF · February 4, 2005

You lose a stop. 45 degrees you lose 2 stops, 22,5 you lose 3 stops and so on.

Images don't really get sharper, but since they have less motion blur this gets percieved by the eye as sharpness. It also introduces flicker and jerky motion since every frame is now less blurred - almost like stop motion. Check out the film that kind of started it all: Saving Private Ryan. There you'll see it's effects very clearly.

Be careful, it doesn't look good on everything and is perhaps a bit overused by now.

Dominik Muench · February 4, 2005

cool thanks guys, thats interesting to know, yeah im not a particular fan of the james ryan style but i was interested in the less motion blurr/sharpness aspect.