Shutter Speeds vs. FPS

Barry_Green said:
And here is where you are wrong. There are many cameras that have the exact same relationship.
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It is a convenience feature, not real mechanical/optical/electronic relationship.

Barry_Green said:
My original rant/question was that if 180 degree shutter is proper for 24p for creating film look, then creating a similar look when shooting 60fps would involve using 1/120 shutter. True or not?
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True.
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I meant, if my target rate is also 60fps. Still true?
 
Cranky said:
But there is no relationship between shutter speed and frame rate when you shoot with a digital camera.
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To elaborate on what Barry said ...

Even though there is no mechanical relationship between framerate and shutterspeed in a digital camera (aside from the fact that you can't have your shutterspeed slower than your frame rate ... ie: 24 fps at 1/12th second isn't possible on any camera), there is a definite relationship when it comes to the final look of movement in the image.

Cranky said:
My original rant/question was that if 180 degree shutter is proper for 24p for creating film look, then creating a similar look when shooting 60fps would involve using 1/120 shutter. True or not?
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Yes, you are right, if you shoot at 60 fps with a 1/120th shutter it will have a film look like it was shot at a "normal" 180 degree shutter IF you slow this footage down to 24p. If not, then it will obviously look very video like.

Cranky said:
Apparently, display frame rate (smoothness vs. stutter) and actual shutter speed (smear vs. staccato) is more important than a holdover from the mechanical past.
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Yes it is, but like I said earlier, the reason I brought up shutter angle in the first place was to provide an understanding of how frame rates relate to shutter speed. If you're trying to go for a "film look" then obviously it would behoove you to understand how film cameras work.
 
dvollrath said:
you can't have your shutterspeed slower than your frame rate ... ie: 24 fps at 1/12th second isn't possible on any camera
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You sure can. You will get duplicated frames, but they will be distinct frames just because the recording section must record a certain number of frames per second no matter what. This is how smeary look is produced.
 
Cranky said:
Still, if you think of it, action is shot at faster actual shutter speed when you overcrank, so I am not sure why it would look the same when you project it with slower rate. The actual image has been shot with fast shutter hence it is recorded sharper than normal images, and if subject moves fast, you will see more strobing. Um, this means that to achieve the same look of strobing subject has to move slower in proportion to overcranked speed. If you do 200% overcrank then the subject must move twice slower to produce the same strobing as normal shooting. Am I right?
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Not exactly. Haha. Think of it like this ...

Imagine your camera is locked on a tripod and you shoot a car moving at 60 miles an hour at 60 fps with a 1/120th shutter speed. Then you shoot the same car moving at 24 miles an hour at 24 fps with a 1/48th degree shutter speed. If you slow down that 60 fps footage to 24 fps, the movement in the scene will look just about identical in both clips.

You are right in the fact that filming a car moving at 60 mph in slow motion will produce a sharper image than regular speed, but that's simply because your the movement in the scene is being slowed down. This is why thinking in terms of degrees helps clear things up. All you're doing is adjusting the look of the movement.
 
What about if we're shooting 60p and are planning to convert it to 24p (reverse telecine or whatever other method) and maintain normal speed in post (I guess not applicable to the 7D but sue me)....1/60 right?
 
Cranky said:
You sure can. You will get duplicated frames, but they will be distinct frames just because the recording section must record a certain number of frames per second no matter what. This is how smeary look is produced.
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Umm yeah that's possible, but regardless of how the media records it, you're ending up with 12 fps if you do that, not 24. I've done that exact effect before in one of my films and it does play at 24p in a timeline, but that doesn't change the fact that the image is really moving at 12 fps.
 
For lots of things like this I highly recommend this book:

http://www.amazon.com/Film-Producti...=sr_1_1?ie=UTF8&s=books&qid=1256241376&sr=1-1

Basically it teaches everything that it took me months of lurking on these forums to learn.

I also recently lost my copy >.<

The latest edition covers video stuff, including specifics like the HVX, a bit about the RED One, color sampling, codecs, etc...

all in all a great book if you have a lot of questions..really excellent IMO.
 
Thanks Camera said:
Can someone give an example of an instance where you'd want to raise the shutter more than twice the frame rate? Action shots?
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If you wanted to freeze the action, for an exaggerated "staccato" look (like the zombies in "28 days later", or pretty much the entire picture "Crank II: High Voltage").
 
You'd have to ask him what it was shot at. Some of it looks like it used a super-short shutter speed (like 1/500 or so) and most of it looks like it's probably around 1/120 or 1/60.
 
Definitely. There are a few shots where the dirt clumps are discrete blocks, and then in most of it the dirt is just a flying cloud of dust... the section from 0:50 to 0:55 looks like high-speed shutter, then the section from 0:56 to 0:59 looks like normal shutter... I think 1:11 to 1:18 is high-speed shutter; it looks like 2:28 to 2:40 is probably all high-speed shutter, etc...
 
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