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Josh Bass

shutter speed question

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You know what I mean. . .the jittery, no-motion-blur effect, where you can even see individual particles as they fly through the air. Shooting at 24p, what is the "proper" shutter speed for this? It seems like there would be an ideal speed, with which to get the greatest noticable effect, and lose the least amount light.

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You WILL lose light doing this because it involves using a shorter-than-normal shutter speed to reduce motion blur and make strobing more obvious.

 

For a 90 degree effect at 24 fps, that's 1/96th of a second, so try something like 1/100th.

 

For a 45 degree effect at 24 fps (what those two films did), that's 1/192nd of a second, so try 1/200th or so.

 

Basically you lose a stop each time you shorten the shutter speed by half.

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If memory serves, there was quite a lot of chat abut this a couple of years ago, and I believe that the answer for what the filmmakers did, lay in the shutter opening angle - something like 45 degrees, which we can't do with our XL's. However, if you shoot in the Manual mode, you will be able to set the shutter speed to somewhere in the range of 150, 180, 210 or 250. You just need to experiment with each of those, depending on how severe you want it to look. Also, at least in Private Ryan - there was some bleach bypass going there.

 

EDIT: Dammit David! How did you get there so fast?

Edited by Jack Barker

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There was a formula I used have written down, an equation, that would convert shutter angles expressed in degrees to shutter speeds expressed in fraction form (1/x). I have no idea where I found it or where it went.

 

We would like the effect to be pretty pronounced, that is, to stand out from 24p footage shot at 1/48.

Edited by Josh Bass

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We just told you the answer...

 

If you want to figure it out mathmatically, you can, but what's the point -- you get the same answers.

 

A shutter in a film camera is a spinning disk. A circle is 360 degrees so a half-circle is 180 degrees, so 180/360 = 1/2. A camera running at 24 fps means that each frame exists for 1/24th of a second in the gate.

 

So 1/24 x 1/2 = 1/48th, the time the shutter is actually open at 24 fps with a 180 degree shutter.

 

So if the shutter is 45 degrees (what "Private Ryan" and "Gladiator" did), then that's 45/360, or 1/8. 1/24 x 1/8 = 1/192, the time the shutter is open. So pick at shutter speed when shooting at 24P that is close to that, probably 1/200th or 1/250th, not knowing specifically what the camera offers.

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Also in addition to 90 and 45 degree shutter Private Ryan did a lot of the Normandy footage setting the shutter slightly out of sync so the negative would be exposed while it was moving. This primarily effects the highlights giving them a vertical streak.

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Also in addition to 90 and 45 degree shutter Private Ryan did a lot of the Normandy footage setting the shutter slightly out of sync so the negative would be exposed while it was moving. This primarily effects the highlights giving them a vertical streak.

 

I wonder if anyone's tried a Streak filter on a video camera to replicate this? Since the streak of a filter or in-camera pulldown affects brighter incoming highlights the most, it's hard to fake it in post once all the highlights are clipped to 100%. It would be hard to get the streak to go only up or down from the highlight source, though (replicating the phase of the shutter in the film camera).

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It would be hard to get the streak to go only up or down from the highlight source, though (replicating the phase of the shutter in the film camera).

 

 

Using the zoom blur in After Effects will streak the highlights in a specific direction.

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Using the zoom blur in After Effects will streak the highlights in a specific direction.

I would be willing to guess, depending on the source, that you might get this effect with a polarizer turned sideways.

Edited by Jack Barker

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Can that "private ryan/gladiator" look be done on a GL2?

 

Doesn't your camera have any shutter speed controls? I'm guessing that it does.

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I'm shooting a doc on birds of pray, at what shutter speed would you suggest to capture the fine detail of the wings, once in flight? I was thinking 1/ 180. (I have a XL1s)

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I'm shooting a doc on birds of pray, at what shutter speed would you suggest to capture the fine detail of the wings, once in flight? I was thinking 1/ 180. (I have a XL1s)

 

 

 

You're running Mini-DV tape right? Have some fun. Splurge. Do some tests.

 

I have a Panasonic 3 chip Mini-DV camera (DVC-30) that has shutter speed settings of 1/4, 1/8, 1/15. 1/30, 1/60 sec. (default) then 1/100

incrementally to 1/8000.

 

It's pretty interesting to shoot 1/8000 at a softball game and get sharp images of the pitched ball, as opposed to the slower shutter speeds, but

be near wide open as opposed to a stop of 16 at 1/60.

 

At 1/4 you can get cool night exposures although if you're not locked off any motion will be crazily blurry. At 1/15 you can get some interesting in camera effects by holding steady and then zooming fast or panning/tilting and everything sharp suddenly streaks.

 

1/30 is great for low light situations. I use it for singer/songwriter performances and get a nicer image than using gain at 1/60 but there is no

noticeable increase in blur that would bother anybody.

 

Also, if you would like some slow motion looks but have to slow down your footage in post if you camera can't overcrank, then shooting birds or anything with a higher shutter speed will help your footage stand up much more crisply in post rather than the typical funky blurring that starts to occur the more you slow down your footage while editing.

 

If the birds of your subject are not easy available for tests, you probably could get a pretty good idea of how your camera will work at various

shutter speeds even if you test shooting your neighborhood pigeons. Not as fast as red tailed hawks I'm sure but still good test subjects I would guess.

 

I did a test with all of the higher shutter speeds on the camera and how they worked when slowed down 10%, 25%, 50%, 90%. If you can slate,

even write on a piece of paper, when you edit you'll remember. Also shoot the same action if possible. Easier with somebody repeatedly swinging at

a softball but I bet if you set up in the local park most pigeons are going to lift off similarly.

 

Good luck.

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I would be willing to guess, depending on the source, that you might get this effect with a polarizer turned sideways.

 

A pola would have none of that effect. You must be confusing it with something else.

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