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18fps vs. 24fps


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#1 Nick Norton

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Posted 02 August 2006 - 10:26 AM

now i know that 24fps is the standard frame rate and that it is easier to blow up to 16mm or 35mm, but what about 18fps?

i'm sure 24fps would look smoother than 18, but what exactly is the difference?

would there be a time you would want to shoot 18 rather than 24?

thanks-

Nick Norton
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#2 John Pytlak RIP

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Posted 02 August 2006 - 10:37 AM

now i know that 24fps is the standard frame rate and that it is easier to blow up to 16mm or 35mm, but what about 18fps?

i'm sure 24fps would look smoother than 18, but what exactly is the difference?

would there be a time you would want to shoot 18 rather than 24?

thanks-

Nick Norton


Use 18fps for "home movies", where you are planning to project the films on a home projector running at 18fps. The slower frame rate was chosen for home movie use to save on film costs.

24fps is the standard frame rate used for professional production, expecially if you intend to transfer to video or "blow up" the image to a larger film format.
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#3 Andrew Means

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Posted 02 August 2006 - 11:59 AM

18fps for poor folks. (like me!)
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#4 Ugo Grassi

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Posted 02 August 2006 - 01:29 PM

At 24 ft/s the sharpness is better because you send more "informations" to your eyes for second.
Don't forget the image informations are in "random" position in every frame. It means: more frame for second more information to your eyes.
The random position of the grain is the reason of the higher quality of chemical image versus the digital cinema.

Edited by Ugo64, 02 August 2006 - 01:33 PM.

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#5 Bryan Darling

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Posted 02 August 2006 - 04:47 PM

I've shot 18fps predominantly in Super 8, whereas I've shot both 18 & 24 in 16mm. I have to say that when projecting the film through a film projector I can't tell a difference. Now I have shot 24fps on certain shots where I may be moving the camera around a lot or in situations where there will be more camera shake, i.e. a out the roof of a car or long end of the zoom. I then project that back at 18fps and it smoothes out the shakes and movements some.

18fps also lets you achieve "slower" slow-motion as 36fps becomes 100% slower, rather than 50% slower when shooting 24fps. I'd shoot both ways, say using one cart, 1/2 at 18fps and 1/2 at 24fps. Shoot something inbetween to help you note where the speed change is. Then project it and/or transfer it at those rates and see how you like it.

Edited by tornsprocket, 02 August 2006 - 04:49 PM.

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#6 Chris Gravat

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Posted 02 August 2006 - 06:56 PM

24 fps is the standard in the united states and some other countries for syncing sound to picture. But if only it was that easy, the camera must be crystal sync to achieve perfectly synced sound. Although if you are shooting at 24 fps without crystal sync you can manage to stay in sync for roughly 25 secs,if you run the camera longer than that your sync will drift when syncing in post.

18 fps, as stated before is "the home movie standard." Sound cannot be synced to 18fps, and when 18 fps is projected at 24 fps the picture appears to be sped up (in the 24 fps world 18fps is called undercranking) All the films you watch at the theater are projected at 24 fps, if theres any fast motion in the film you are watching at the theater then it was shot at a lower frame rate (undercranked.) The opposite is overcranking= slow motion (36fps, 48fps etc.) when projected at 24 fps.

Hope this answered your question.

- Chris Gravat
Orlando, FL
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#7 Eric Maxwell

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Posted 28 August 2006 - 02:43 AM

I recently shot a super 8 short that used both 24 and 18 fps and the difference, at least at home on a television, is very small. For the bits in the story that take place in reality I used 24, but in fantastic or unreal situations, I used 18 for a slightly dream like look.

Though this isn't the best indicator at all, use any editing system that can render the footage at different frame rates and save a video file at both 18 and 24 fps. True, there are a lot of other factors in film, but the video test is a start.

Also, I believe that significant sections of Guy Maddin's "The Saddest Music in the World" were shot in 18fps, both on super 8 and 16mm.
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#8 David Leugers

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Posted 28 August 2006 - 11:23 AM

While I am not a "24fps" snob, I have shot all my movies (R-8mm, S-8mm, 16mm) at 24fps. I like the quality and smoothness. Back in the day when we all edited our films using a splicer, the splices were much less visable on screen at 24fps. In that vein, defects on the film are also less noticeable as well. Lots of reasons to shoot in 24fps, but 18fps is certainly OK if that is your preference.
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#9 Sean McHenry

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Posted 15 October 2006 - 11:48 PM

Note that it would be tough to get a professional blow up or even video transfer to beta or other video format at 18. I am sure a few places can do it but the accepted norm is still 24 for released theatrical films. It would be like expecting a PAL video to be accepted here in the US. It can be converted to our US NTSC standard but why not just shoot it right in the first place. Sure, it can be cool or you can use it for an old time hand cranked feel, like the really old Chaplin films or something. Unless you want higher speed playback, the opposite fo Slow-Mo, it is more a bother than it's worth I would think.

Most NLE programs aren't set up for 18fps either. Some can do PAL native (25fps) but all will be looking for 24, especially if you are converting to NTSC on the way in or out of the NLE.

You really won't save all that much film if you are going 18 vs 24 anyway, at least for a short. Would make a big difference of you were doing a feature, but if you were doing a feature, you would want to shoot the accepted norm of 24 fps.

Sean

Edited by Sean McHenry, 15 October 2006 - 11:51 PM.

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