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Low shutter angle


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#1 Neil Randall

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Posted 21 March 2007 - 03:34 AM

Hi,

Got a short and coming up wanted to achieve a low-shutter-angle look for a small murder scene, something between 15 and 45 degrees.

Can anyone illuminate me to the methods for achieving this, please? I'm having trouble understanding the relationship between shutter speed and FPS. We'll be shooting 24p and I'm not convinced shutter speed is digitally-synonymous with the shutter angle on a film camera.

I'm also open to suggestions for affecting it in post.

Thanks,

NR
Obscura Films Ltd.
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#2 Michael Nash

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Posted 21 March 2007 - 03:53 AM

We'll be shooting 24p and I'm not convinced shutter speed is digitally-synonymous with the shutter angle on a film camera.



It is -- shutterspeed is shutterspeed. The shutterspeed per frame from a 180 degree film camera shutter at 24fps is 1/48 second. A 90 degree shutter is 1/2 that, or 1/96 second. 45 degrees = 1/192 second. The math is straightforward.

With video the selectable shutterspeeds are often in steps that don't perfectly match those produced by film shutterangles, so you might round off to 1/100 or 1/200 for the above examples. If you need to be more precise, you can use the Clearscan (Synchroscan) to dial in a precise shutterspeed.

Post manipulation cannot replicate the look of a short shutterspeed. A moving subject captured at 1/200 second shutterspeed has very little motion blur per frame. In post you can sometimes add motion blur, but you can't take it away.
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#3 Neil Randall

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Posted 21 March 2007 - 04:06 AM

It is -- shutterspeed is shutterspeed. The shutterspeed per frame from a 180 degree film camera shutter at 24fps is 1/48 second. A 90 degree shutter is 1/2 that, or 1/96 second. 45 degrees = 1/192 second. The math is straightforward.

With video the selectable shutterspeeds are often in steps that don't perfectly match those produced by film shutterangles, so you might round off to 1/100 or 1/200 for the above examples. If you need to be more precise, you can use the Clearscan (Synchroscan) to dial in a precise shutterspeed.

Post manipulation cannot replicate the look of a short shutterspeed. A moving subject captured at 1/200 second shutterspeed has very little motion blur per frame. In post you can sometimes add motion blur, but you can't take it away.


Thanks for that. I just followed your maths example and now I understand - I think! For 24p, the shutter angle (as represented as a division of 360 deg) equates to the number of times to multiply the FPS speed (24, in this case) expressed in fractions of a second.

So, if my logic is clear, at 24 FPS, a 120-deg angle would equate to 1/72 of a sec?

I'm sure I've seen the formulae - they're obviously a lot more succinct.

The panny has a 1/250 setting. Have you used this speed? I'm looking for a near-strobing but not stop-frame look.

Thanks again,

NR
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#4 Neil Randall

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Posted 21 March 2007 - 04:18 AM

Pasadena? You're up late/early, mate. :)
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#5 Michael Nash

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Posted 21 March 2007 - 04:19 AM

So, if my logic is clear, at 24 FPS, a 120-deg angle would equate to 1/72 of a sec?


Correct.

With video, what you-see-is-what-you-get. Try out different shutterspeeds and see what you like.

In my experience a 90 degree shutter (1/100) is enough to look "different" but not extreme. A 45 degree shutter (1/250 or so) is pretty pronounced. Any more than that and you start to lose quite a bit of light, and it really only pays off with very fast-moving action.

I recently shot a story about a tennis player and decided to use a fast shutter to add a dramatic touch to otherwise mundane footage. I found that 1/500 gave really cool strobing on the racquet swings, and at the long end of the lens and wide open it dropped the MTF on that lens a bit. The soft optical quality with the hyper-crisp motion looked kinda surreal...
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#6 Neil Randall

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Posted 21 March 2007 - 04:35 AM

Correct.

With video, what you-see-is-what-you-get. Try out different shutterspeeds and see what you like.

In my experience a 90 degree shutter (1/100) is enough to look "different" but not extreme. A 45 degree shutter (1/250 or so) is pretty pronounced. Any more than that and you start to lose quite a bit of light, and it really only pays off with very fast-moving action.

I recently shot a story about a tennis player and decided to use a fast shutter to add a dramatic touch to otherwise mundane footage. I found that 1/500 gave really cool strobing on the racquet swings, and at the long end of the lens and wide open it dropped the MTF on that lens a bit. The soft optical quality with the hyper-crisp motion looked kinda surreal...


Ta. I think I'll try out 90 or 45 and see what sticks.

As for MTF, that goes a bit beyond my technical expertise. I'm a bit of a jack but no master - oh, and new to direction.
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#7 Michael Collier

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Posted 21 March 2007 - 01:58 PM

Hes just saying that since he shuttered down he had to open wide. Most lenses will go soft when you open full wide. MTF I am not entirely sure on myself, but I know its a measurement of the lenses resolution. Modular Transfer Function? Is that what the acronym stands for? I heard that somewhere.

1/500 is really nice, thats my standby shutter when I want shutter look. 1/1000 is good too, 1/2000 is a bit much for me. 1/100 and 1/250 I mostly use to reduce DOF (In my ENG work I don't have the time to slap some ND on there like I should, nor do they provide me with the filters) Those do however impart a bit of the shutter look, esp 1/250. good for a subtle effect.

Best part is you can experiement on any camera. Any camera capable of turning the shutter on will show you. It doesn't have to be the camera your going to use, since 1/2000 of a sec is the same on any camera.
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#8 Michael Nash

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Posted 21 March 2007 - 06:17 PM

Best part is you can experiement on any camera. Any camera capable of turning the shutter on will show you. It doesn't have to be the camera your going to use, since 1/2000 of a sec is the same on any camera.


Well almost. Interlaced capture appplies the shutterspeed to each field, but progressive scan applies that shutterspeed to the whole frame. 60 samples of 1/2000 second starts to look pretty different from 24 samples of 1/2000 sec.

This is one reason I said a 45 degree shutter looks pretty pronounced on a film camera at 24fps. That "frozen" motion is held on screen for a longer amount of time, making motion more noticeably strobed. At 60i there's less time between frames, so you can have more fluid-looking motion at faster shutterspeeds.

MTF is modulation transfer function, in short a measure of the contrast and resolution of a lens under certain conditions. I just meant the image started to get soft and murky-looking in a uniquely "optical" way.
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#9 Neil Randall

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Posted 22 March 2007 - 04:13 AM

Well almost. Interlaced capture appplies the shutterspeed to each field, but progressive scan applies that shutterspeed to the whole frame. 60 samples of 1/2000 second starts to look pretty different from 24 samples of 1/2000 sec.

This is one reason I said a 45 degree shutter looks pretty pronounced on a film camera at 24fps. That "frozen" motion is held on screen for a longer amount of time, making motion more noticeably strobed. At 60i there's less time between frames, so you can have more fluid-looking motion at faster shutterspeeds.

MTF is modulation transfer function, in short a measure of the contrast and resolution of a lens under certain conditions. I just meant the image started to get soft and murky-looking in a uniquely "optical" way.


Thanks for the info guys. I get you on MTF - I'd heard of it, but only seen it in graph form. Understand the softness concept.

I've got a Panny GS-500 camcorder with switchable shutter speeds, so I'll muck about with it to see what gives. I think the 'Movie Mode' switches to progressive.

Thanks again.

NR
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#10 Michael Nash

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Posted 23 March 2007 - 01:43 AM

Pasadena? You're up late/early, mate. :)


I'd been working overnights and was still adjusted for those hours. Now I'm on a morning project and suffering for it...
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#11 Neil Randall

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Posted 23 March 2007 - 03:39 AM

I'd been working overnights and was still adjusted for those hours. Now I'm on a morning project and suffering for it...


Nasty. But think of it this way: you're getting paid to do what you love. I have to sub-edit inane local news for a paper. Although, there's always time for research in between stories... B)
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