Yes I can see you point. Not sure I agree that 180 shutter angle is always right but I do see that if things are slowed right down they need to be sharper with less motion blur. Shooting at 60P with 1/60 will be a lot sharper than 24P at 1/48 because there are more frames of information and the motion between each frame is a lot less. I guess that is the point I was trying to make. If it is easier just to use 180 universally thats fine but you may get exactly the same performance with less shutter speed and consequently better performance from the camera in lower light without needing lights or using gain. I routinely take stills from my video shot at 60P with 1/60 shutter. If there is enough light I use 1/90 but I cannot recall ever using 1/120.
GH4 Proper shutter angle for various VFR slow motion speeds?
- Thread starter filmguy123
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Ron, I'm certainly no expert, but I THINK the thing you're overlooking is that motion blur is dependent on frame rate in the sense that for every frame exposed within a second it is exposed at a specific duration dictated by the frame rate.
At least in my mind, if regular 24fps footage exposes 24 separate frames over the span of one second, each frame is exposed for 0.04166 seconds. (1 second divided by 24 frames)
And if 60fps footage exposes 60 separate frames over the span of one second then each frame is exposed for 0.01666 seconds. (1 second divided by 60 frames)
This obviously isn't the case when taking stills as the shutter speed is the only thing dictating the duration of exposure. I THINK that is possibly the difference in how your viewing it. But because moving footage has its frames' duration of exposure dictated by how many frames it needs to expose per second, the shutter speed would need to adjust with the frame rate to maintain the similar motion blur.
But I could be talking out of my ass
No that is not true. The sensor isn't exposed for the duration of the frame that is what shutter speed is used for. Shutter speed is shutter speed and will be responsible for motion blur just like a still camera. The frame rate is independent of shutter speed other than of course it has to be less in most instances ( not all as there can be accumulation ). It is exactly the same as taking a still image. Video is just a series of still images with all the same parameters. As I have conceded the slow motion needs to be sharper otherwise it will look blurred compared to the normal motion since it is moving slower it needs to be sharper. The slower it moves the sharper it needs to be. Understood now. I still have the issue that I do not feel that using 180 is always correct or needed to achieve the end result. The faster the frame rate the less movement there is between frames anyway and an appropriate shutter speed to capture this level of movement is all that is needed. At 24P the rule is important as going slower leads to mush and going faster leads to choppy motion ( cadence or whatever you might like to call it ) This becomes less important as the frame rate increases and for me always shooting at 60P exploiting the available light is more important in choosing shutter speed. Once the shutter speed effectively stops the motion there is little point in going faster.
joe12south
Veteran
You don't have to use 180º unless you are trying to match the traditional film-look. The point is that your VFR shutter speed and VFR frame rate both need to use the same matching multiple of the base frame rate and shutter speed so that when converted, they both scale proportionately.
joe12south
Veteran
No, shutter speed is shutter speed. Exposing for 1/48 of a second is 1/48 of a second, no matter if you do it once a month, or 24 times a second. Only caveat being that you can't set a shutter speed lower than the frame rate as that would be physically impossible.Ron, I'm certainly no expert, but I THINK the thing you're overlooking is that motion blur is dependent on frame rate in the sense that for every frame exposed within a second it is exposed at a specific duration dictated by the frame rate.
At least in my mind, if regular 24fps footage exposes 24 separate frames over the span of one second, each frame is exposed for 0.04166 seconds. (1 second divided by 24 frames)
And if 60fps footage exposes 60 separate frames over the span of one second then each frame is exposed for 0.01666 seconds. (1 second divided by 60 frames)
This obviously isn't the case when taking stills as the shutter speed is the only thing dictating the duration of exposure. I THINK that is possibly the difference in how your viewing it. But because moving footage has its frames' duration of exposure dictated by how many frames it needs to expose per second, the shutter speed would need to adjust with the frame rate to maintain the similar motion blur.
But I could be talking out of my ass
With electronic devices like these, you can set a lower shutter speed than frame rate, but it often results in multiple frames of the same image. Our JVC cameras at work will go down to 7fps electronic shutter speed, the video coming out of that is just garbage with multiple frames of the same image (720/59.94), and yet the students don't seem to notice when this happens and they are shooting. Lets in lots of light though.
joe12south
Veteran
Well, that's a glitch. A frame can't be exposed for longer than the duration of a frame.
Thomas Smet
Veteran
https://www.youtube.com/watch?v=-nHM4_VkV_I
https://photography.tutsplus.com/articles/quick-tip-how-does-shutter-speed-affect-video--photo-12092
Excerpt from the above link...
"Finally, when shooting high-speed for slow motion video, the 180° shutter angle is still the best-looking option. Common sense says that when shooting at 60p to conform to 24p, a 360° shutter would be best to maintain approximately the same level of motion blur as a 180° shutter at 24p. However in practice, this doesn't work, as our eyes understand the slow motion and still expect to see a 180° shutter angle along with the associated reduced motion blur.
This is related to a phenomenon called cadence, which is the amount or quality of motion of subjects between frames. Just like the 180° shutter angle itself, our media-saturated brains understand cadence well and adjust accordingly.
Oddly, the 360° shutter at 60p looks blurry, even though it's about the same magnitude as 24p 180°. The motion doesn't look so bad at 90° either; perhaps this is because action scenes are frequently shot at narrower shutter angles to reduce motion blur."
Sometimes Hollywood does use 180 degrees and sometimes more like 90 degrees. All depends on how crisp they want the slow motion to look. Since everything moves slower and there are not as many sudden changes between each frame less motion blur can be used to see the details on the subject in slow motion. Nobody ever does 360 degrees however which really defeats the entire point of slow motion which is to really focus on the details on the screen.
Sometimes slow motion is faked. Mel Gibson loves to act out slow motion as opposed to having the camera actually shoot in slow motion. In those cases the film is still shot at 24p with a 180 degree shutter and so any slow motion you would shoot with the camera as opposed to the actors faking it to make it should have that same feel.
The opposite is also true for time-lapse video and the shutter should be halved in the opposite direction based on how much you plan on speeding up the material. This helps add more motion blur to the sped up material so it look natural as if people and cars could really move that fast and were shot with a 24p 1/48th camera.
https://photography.tutsplus.com/articles/quick-tip-how-does-shutter-speed-affect-video--photo-12092
Excerpt from the above link...
"Finally, when shooting high-speed for slow motion video, the 180° shutter angle is still the best-looking option. Common sense says that when shooting at 60p to conform to 24p, a 360° shutter would be best to maintain approximately the same level of motion blur as a 180° shutter at 24p. However in practice, this doesn't work, as our eyes understand the slow motion and still expect to see a 180° shutter angle along with the associated reduced motion blur.
This is related to a phenomenon called cadence, which is the amount or quality of motion of subjects between frames. Just like the 180° shutter angle itself, our media-saturated brains understand cadence well and adjust accordingly.
Oddly, the 360° shutter at 60p looks blurry, even though it's about the same magnitude as 24p 180°. The motion doesn't look so bad at 90° either; perhaps this is because action scenes are frequently shot at narrower shutter angles to reduce motion blur."
Sometimes Hollywood does use 180 degrees and sometimes more like 90 degrees. All depends on how crisp they want the slow motion to look. Since everything moves slower and there are not as many sudden changes between each frame less motion blur can be used to see the details on the subject in slow motion. Nobody ever does 360 degrees however which really defeats the entire point of slow motion which is to really focus on the details on the screen.
Sometimes slow motion is faked. Mel Gibson loves to act out slow motion as opposed to having the camera actually shoot in slow motion. In those cases the film is still shot at 24p with a 180 degree shutter and so any slow motion you would shoot with the camera as opposed to the actors faking it to make it should have that same feel.
The opposite is also true for time-lapse video and the shutter should be halved in the opposite direction based on how much you plan on speeding up the material. This helps add more motion blur to the sped up material so it look natural as if people and cars could really move that fast and were shot with a 24p 1/48th camera.
Yea I'm aware of how the shutter speed works, I was more so getting at the fact that higher frame rates have less motion from one frame to the next as Ron ended up saying.