GH3 Shutter Speed - 24fps and 60fps

Barry_Green said:
You cannot have a shutter speed that's of longer duration than your frame rate. It's simply not possible.
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Actually it is possible by doing a sneaky trick - let's say you're shooting 24P in very low light, and you need to use a shutter speed of 1/12 sec to get a good exposure. Go ahead and do it. Of course you're only recording 12 frames per second. But, in post you can use Twixtor or something similar, to create in-between frames which will get you back up to 24 fps. I've actually done it. It works quite well as long as you use a tripod, and objects in the frame move relatively slow.
 
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Barry_Green said:
Not sure where you're headed with this, but -- in terms of a film camera, it is absolutely true. For any given frame rate (number of frames per second), the shutter speed is a fixed speed, and if you change the frame rate, it will indeed change the shutter speed. That's what the whole "180 degree rule" is about... and so, if trying to emulate the look of film, you indeed would want to change the shutter speed to the appropriate speed for the given frame rate.




If trying to emulate the look of a film camera, yes.

True, but that's how film works.


Okay, that's absolutely not correct, because it's completely impossible. You cannot have a shutter speed that's of longer duration than your frame rate. It's simply not possible.


The very slowest shutter speed you can ever have, for 240 frames per second, is 1/240. It is impossible to get 1/60th. If you did somehow set the shutter speed to 1/60th, the only way the camera could accomplish that would be through frame duplication, which would mean you really wouldn't get any more than 60 distinct frames per second.
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I was referring more to 30p, 60p and 60i and not so much film look. You are correct about the 240p thing. It should be 1/240th to mimic the look of 60p/60i video. I guess where the confusion is for some people is why 60p/60i uses 1/60th and why 30p also uses 1/60th instead of 1/30th. Well you can but 1/30th starts to get too much motion blur. The higher the framerate the less blur you will have with the shutter differences.

Outside of slow motion I see very little reason to continue to follow the 180 degree rule once you get higher then 24p. You already have a motion signature very different than 24p and sticking to the 180 degree rule isn't going to give you that film look anymore. You already moved far away from the film look. Even with 48p we are now creating a look so far away from the traditional 24p film look that the 180 degree rule doesn't have the same impact. The Hobbit was shot at 48p with a shutter of 1/72th and not 1/96th. Yes that is to support the 24p version of the film so it doesn't look to jittery but already we are starting to see the 180 degree rule breaking at 48p. If we ever go higher the rule will be even less important since there is so little space between frames for there to be excessive motion blur.
 
The 180 degree rule really isn't a rule. It is a by product of film.

You really should choose your shutter speed based on what you want the footage to look like. If you want motion blur select a longer shutter duration. If you want more defined images select a short duration. If you want it to look like film then choose a frame rate and shutter speed that matches what film used.

There is no blanket right or wrong answer here. Whatever achieves the "look" you are after is what you should try to use.
 
Sorry to bump this thread guys.

I tried the 180 degree rule (60fps 1/125 shutter speed) on my GH3 and interpreted it as 24p in premiere pro to slow it down. Also did it with 1/400 and 1/800 shutter speeds to see how much this would stray away from the film look, and I am honestly not seeing much of a difference. What exactly am I doing wrong here ? Is utilizing the 180 degree rule that noticeable on these cameras ? Because if not, then I won't have to send back my 7-14mm and pick up a 9-18mm and figure out some sort of magic ND filter setup.
 
anchoricex said:
Also did it with 1/400 and 1/800 shutter speeds to see how much this would stray away from the film look, and I am honestly not seeing much of a difference.
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Is anything moving quickly in your shots?

The high shutter speed should give you a taste of the "Saving Private Ryan"/"Gladiator" action scenes when things are moving quickly.
 
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