Motion Blur/Strobbing

N

NSBFTW

Carbonite Member
Alright so what is the difference between the two and how my shutter speed effects either in 720 60p. I normally have my shutter off, but if I crank it to something like 120 there wont be motion blur but the footage will me more choppy?

I don't really understand, I understand that the shutter will let in less light when higher and is choppier when set below the frame rate but what about higher?

What is strobing then, is it the same as motion blur?
 
Strobing is a result of shutter speed not syncing with the lights. Lights have a natural strobing that occurs that generally the eye doesn't notice due to we have continuous vision (no shutter or fps). blurring is a result of action happening and the shutter being slow (1/24-1/50 generally) so that it appears blurred.

Think of blurring it in photography terms is generally the way to make it more clear. When you take a picture of somebody running with a shutter speed slower than 1/100, you likely will have nothing but blur. but the faster your shutter is, the less blur you will have.

Basically, for the most smooth and natural looking footage, it's generally recommended to keep your shutter below 1/100th of a second. If you are shooting with a faster shutter you need to be aware of the style changes.

Test shoot with different shutter speeds, then play back in slow-motion to exaggerate the difference.
 
NSBFTW said:
Alright so what is the difference between the two and how my shutter speed effects either in 720 60p.
Click to expand...

The Oxford Dictionary website defines stobing as "jerkiness in what should be a smooth movement of an image on a screen". If the movement between frames is too great (e.g., when the cameraperson pans too rapidly), the viewer observes a choppiness or jerkiness because successive frames are different enough to be noticeable. Motion blur is the blur within individual frames when the movement during the exposure of the frame is faster than the shutter speed is able to "stop". Obviously, the concepts are related. Indeed, motion blur often helps to "hide" stobing. If you shoot fast movement with a very fast shutter, the individual frames will be very sharp (i.e., no blur), but stobing will be very visible. On the other hand, if you shoot with a slower shutter, the individual frames will be blurred in the areas of movement. The blur will reduce somewhat the difference between successive frames, and that will reduce the jerkiness.

The standard rule of thumb for film is what is called a 180 degree shutter. In other words, the shutter is open for half the frame time. At 24 frames per second, that means the shutter speed is 1/48. At 30 fps, it is 1/60; and at 60 fps, it is 1/120. Over the years, people have become accustomed to the look of a 180 degree shutter. Generally speaking, you should deviate from it only when you have good reason. (That means testing in advance to be sure that you like the result!)
 
I think you need to read up on frame rates and shutter speeds.

Real low frame (ie 24p - same as film) rate will often look strobey when there is significant motion. You need to pan slower etc.
A high frame rate (ie 60P) will look more "real" - not like film) and fast pans will not seem to strobe.

Low shutter can cause motion blur, (similar to how a still cam works). While the ratio for "normal" looking footage is as rpcx says ( one half or 180 deg the frame rate, ie. 1/48 for 24P) you will get more motion blur with 1/24 shutter with 24P framerate than 1/60 shutter with 60P frame rate.

To think of it in still camera terms:
Frame rate is how many pictures are shot per second.
Shutter speed is how long per picture the iris is open.
 
So what happens when the shutter is off? Is it really off or just in 1/60? I film a lot of skateboarding and want to know what I should be doing, stay at 1/250 usually and when I need light go down to 1/120, even 1/60.0?

Doesn't shutter speed induce motion blur the higher it is? So if it was off there would be no motion blur?
 
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really low shutter = motion blur.
real high shutter = "stuttering" look (think Saving Private Ryan).
 
if you put the shutter speed all the way up to 1/1000 - 1/2000, you can point your camera out the window of a car traveling at 90kph / 55mph (give or take). Then when you pause on the playback you will get a perfect still. The shutter moving so fast also makes the picture a lot darker. I'd love to see what a cmos camera looks like if you did that!
 
NSBFTW said:
So what happens when the shutter is off? Is it really off or just in 1/60?
Click to expand...

Depends on what camera you're talking about. "Shutter Off" on an HPX2000 or above, means no shutter. When shooting 24p, the shutter would be 1/24. When shooting 60i, the shutter would be 1/60th.

But on a Panasonic AG-series, "shutter off" doesn't mean that at all, instead it means "shutter default". So 1/50 on a PAL camera, 1/60 on 60i/60p, and 1/50 on 24p/30p.
 
Barry_Green said:
Depends on what camera you're talking about. "Shutter Off" on an HPX2000 or above, means no shutter. When shooting 24p, the shutter would be 1/24. When shooting 60i, the shutter would be 1/60th.

But on a Panasonic AG-series, "shutter off" doesn't mean that at all, instead it means "shutter default". So 1/50 on a PAL camera, 1/60 on 60i/60p, and 1/50 on 24p/30p.
Click to expand...
Thanks for clearing that up Barry!
 
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