GH3 about fps to shutter speed rule

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stefanocps

Well-known member
hi please help me on remember about this when shooting with dslr
i know that shutter speed should always be the double of fps.is it like that?
so that if i shot ad 25fps i should use 50ss
but what if i want to use 50 fps to have better quality?
settings ss at 100 will result in loosng so many stops
please refesh my Learning
thanks!
 
except you don't have to ALWAYS follow those rules.
(I don't think I have ever shot at twice / 180 rule)
 
No, the rule is designed to somewhat mimic the 180 degree shutter of real filming. And it does pretty well mostly. Its compeletly depends on the look you want to achieve.

High shutter speeds (smaller shutter angle less than 180): each frame is cleaner - think SAVING PRIVATE RYAN action beach scene, requires more light

Low shutter speeds (wider angle: up to 360): each frame can blur more, and gather more light - think smeary, blurry, but kinda smoother looking

Twice the frame rate (180 angle in film cameras) is the mid point, and GENERALLY works ok for most people. "Quality" is relative.
 
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I most often shoot a slower shutter than double the frame rate. I greatly dislike the strobing effect of a 180 shutter in 24p.

Digital acquisition is much different than film that 180 degree shutter was coined for. In digital work, the frame is shown for the full duration of the 1/frame rate. In film there is a space/duration that is black where the film is moved between frames. These two concepts are so different that they can never truly look the same.

I most often shoot at 1/60th of a second for 60p and 1/30th for 4K 30p. I never shoot 24p as it always looks terrible to me. The only time I shoot 180 degree shutter is when doing action sports.

My lastest fun shoot I shot at 96fps and 1/100th shutter if you want to see what that looks like. https://vimeo.com/128570651

Cheers,
Pete
 
I wouldn't go less than 1/fps, it just looks bad. but there is no technical reason not to go as low as 1/fps if you have that setting, as mentioned above there is no mirror for the operator and you don't need the dark space to advance the film to the next frame. So you should be fine at 1/50 shutter speed when shooting 50p material.

You might want to try shooting at a shutter speed less than your frame rate so you can see how it looks. The look may change from camera to camera because not every camera will handle the frames the same way/ Our JVC ENG cameras will do 7fps in any recording mode, you get lots of light, but it looks like 7fps even though the frames are clicking by at 59.94 per second. It's an effect that you might want to use, but mostly it is a mistake that some of our students make and somehow don't see in the viewfinder while they are shooting :huh:
 
stefanocps said:
but what if i want to use 50 fps to have better quality?
settings ss at 100 will result in loosng so many stops
Click to expand...
That is just the unfortunate reality of shooting at a higher frame rate. Since you are shooting more frames per second, it by necessity requires a faster shutter speed, and therefore more light.
 
stefanocps said:
hi please help me on remember about this when shooting with dslr
i know that shutter speed should always be the double of fps.is it like that?
so that if i shot ad 25fps i should use 50ss
but what if i want to use 50 fps to have better quality?
settings ss at 100 will result in loosng so many stops
please refesh my Learning
thanks!
Click to expand...

It depends on what the 50fps is for.

Most people use the 180 degree rule as a blanket rule and this is wrong. TV has always been shot at 60p, 60i, 50p or 50i. Those frame rates were almost always accompanied by a 1/60th or 1/50th shutter. Yes 50p has the same motion as 50i if you intend on playing that material as 50 fps. This is the "normal reality" look of video.

Now if you intend on using that 50p for slow motion then yes you would use 1/100th shutter. This is because ultimately those frames will be played back at 25fps so that 100th shutter becomes a 1/50th shutter to match the 25fps in slow motion.

Why is normal TV at 50p(i) shot with a 1/50th shutter? Not sure for the reasoning I just know it has been that way for 50+ years. It likely has to do with creating a buttery smooth motion the ways humans see things. The 180 degree rule is a by product of film making.

With that said there is nothing wrong with shooting 50p at 1/100th shutter. In fact you can shoot at whatever shutter speed you want to. Some movies even shoot at a different shutter speed for a specific look like Saving Private Ryan which used a 45 degree shutter for less motion blur and a gritty harsh feeling.
 
Basically what Thomas recommends: 1/60 for 60P, 1/60 or a little slower for 30P, 1/48 or a little slower for 24P.

1/120 for 60P looks odd, except when the footage had been slowed.
 
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