Frame rate/shutter angle question

[Steven Caesare]

So, with digital sensors not having a physical shutter, and thus being able to shoot a 360-degree shutter, would a frame taken at 48fps/360-degrees look the same as a frame taken at 24fps/180-degrees?

IOW: could you shoot 48/360 and use every-other-frame for a 24FPS cinema release, and yet have a 48fps "psuedo Showscan" version?

-sc

 

[Stuart English]

Image Capture

Image Capture

Yes, if you captured 48 fps / 360 degrees and dropped every frame it would look very similar to a 24 fps / 180 degrees capture.

 

[Steven Caesare]

Thanks Stuart.

I'd be interested in seeing both the 48fps and 24fps streams extracted from the same set of footage taken.

Seems like it might be a cool way to shoot, and perhaps be prepared for digital projectors as they may be much more flexible for frame rates in the future...

-sc

 

[David Mullen ASC]

You may find 48 fps with a 360 shutter looking a bit "video-ish" however -- typical interlaced-scan NTSC video is shot at 60i with no shutter (1/60th) so basically the look is the combination of a high motion sampling rate (60X) with no light-dark interval from a shutter, no temporal gaps. So 48 fps with no shutter is going to look a bit similar.

 

[Steven Caesare]

That makes sense.

Although I do find that 24fps material on my projector, which displays at a 96Hz refresh rate, continues to look film-like despite having no light-dark squence due to lack of shutter interval.

Your point about the highr framerate is a good one, althouh I wonder how well it would do at eliminating judder from the 24fps rate, yet not look to videoish because it would still have similar motion blur as a result of the 1/48th second exposure time.

Has anybody tried this?

-sc

 

[David Mullen ASC]

That makes sense.

Although I do find that 24fps material on my projector, which displays at a 96Hz refresh rate, continues to look film-like despite having no light-dark squence due to lack of shutter interval.

Your point about the highr framerate is a good one, althouh I wonder how well it would do at eliminating judder from the 24fps rate, yet not look to videoish because it would still have similar motion blur as a result of the 1/48th second exposure time.

Has anybody tried this?

-sc

I think 48 fps is going to look even better with a 180 degree shutter, i.e. 1/96th of a second. Shorter shutter speeds allow sharper images and higher frame rates allow them to not strobe as much, so turning off the shutter at 48 fps reduces one of the advantages of shooting at 48 fps, the shorter shutter speed.

 

[Steven Caesare]

I think 48 fps is going to look even better with a 180 degree shutter, i.e. 1/96th of a second. Shorter shutter speeds allow sharper images and higher frame rates allow them to not strobe as much, so turning off the shutter at 48 fps reduces one of the advantages of shooting at 48 fps, the shorter shutter speed.

It seems that some of what people object to in the discussions I've seen on the "we need higher framerate" debates is the lack of motion blur in each frame making it look too crisp and "video-like".

Sort of how the Gladiator battle squences were obviously different depsite still being 24fps.

So I wonder if we could eliminate some of the judder of 24fps, but make the motion look "smooth" as we've become accustomed to with enough blur in each frame.

Plus the side advantage would be the ability to extract a cinema-friendly stream by using every other frame.

Not arguing with you David... I'd love to see some of the different ideas tried so we could compare.

Thanks.

-sc