So is 24 frames per second "good enough"

[Jeremy Neish]

very sorry for being the moron but

if you shoot 48 fps or 60 fps what do you set your shutter speed at to get 180


this has always confused me a bit :confused5:

As I understand it, they are independent of each other, 180 will always give you the same amount of motion blur in a given frame no matter the frame rate. In the video world frame rate and shutter rate are tied together, making it more confusing to me. I prefer the "film" terminology, because they are independent.

 

[Bruce Allen]

But, you have probably not seen high framerate shown in a theatre with proper cinematic projection, etc.

Having been a part of a lot of high-framerate stereoscopy projection tests, I can tell you that when all the piece of the projection chain are there, it's mind-blowing.

I'm in your camp for sure, Lucas.

I like 24fps for 2D but once you go 3D, 48fps+ is great. And preferably 4K as well, right 2D film is like a dream. 3D is about being there. I like my live theatre, opera, etc at >24fps so why not my drama?

BTW, if you had to choose - what do you think feels better for 3D - 4K at 24fps or 2K at 48fps?

Bruce Allen
www.boacinema.com

 

[Roberto Lequeux]

Motion blur has to do with the actual amount of motion (subject speed across the frame), and shutter speed. 180 is half, so 24fps gives you half of 1/24th for each frame, etc... if a camera can record 48fps using 1/48th shutter then you are recording double 24fps with the same exact exposure time, meaning same motion blur, required exposure, etc... and since 48/2=24 you can drop every other frame and get the same exact thing you woulda gotten if you shot 24fps 1/48th. So, for archival purposes, shooting 48fps 1/48th would be great. However, you would need the sort of player Michael posted to be able to watch the fishies, barracudas, sharks, mermaids, etc... in their 48fps glory, or wait till everything is delivered through the www channels where you could theoretically broadcast whatever the heck TVs can handle.

The interesting thing would be to do some tests from 60fps to 24fps with the latest software, or perhaps safer, from 48 to 60.

I'm in your camp for sure, Lucas.

I like 24fps for 2D but once you go 3D, 48fps+ is great. And preferably 4K as well, right 2D film is like a dream. 3D is about being there. I like my live theatre, opera, etc at >24fps so why not my drama?

BTW, if you had to choose - what do you think feels better for 3D - 4K at 24fps or 2K at 48fps?

Bruce Allen
www.boacinema.com

Interesting point. I am still a fan of the "dream" though.

 

[Rick Burnett]

Motion blur has to do with the actual amount of motion (subject speed across the frame), and shutter speed. 180 is half, so 24fps gives you half of 1/24th for each frame, etc... if a camera can record 48fps using 1/48th shutter then you are recording double 24fps with the same exact exposure time, meaning same motion blur, required exposure, etc... and since 48/2=24 you can drop every other frame and get the same exact thing you woulda gotten if you shot 24fps 1/48th. So, for archival purposes, shooting 48fps 1/48th would be great. However, you would need the sort of player Michael posted to be able to watch the fishies, barracudas, sharks, mermaids, etc... in their 48fps glory, or wait till everything is delivered through the www channels where you could theoretically broadcast whatever the heck TVs can handle.

The interesting thing would be to do some tests from 60fps to 24fps with the latest software, or perhaps safer, from 48 to 60.

I don't see how you can ever shoot 1/48 at 48fps. With a single sensor, that gives you no time to read or reset the pixels.

 

[Roberto Lequeux]

I don't see how you can ever shoot 1/48 at 48fps. With a single sensor, that gives you no time to read or reset the pixels.

I know what you mean, but even my HVX let me do this. I'll leave that up to the camera manufacturers.

It doesn't seem that far fetched for a camera with a 1.5 Gigapixel processing power though...

 

[conrad gaunt]

I don't see how you can ever shoot 1/48 at 48fps. With a single sensor, that gives you no time to read or reset the pixels.

I can shoot 48fps @ 3k with a 1/48sec shutter, right now

what you're describing is a theoretical 360deg, something a film camera can't do, but existing R1s can. Its not a great shutter angle to use if you want a film look, but then a R1 isn't "film" camera.

a 180deg shutter, at 48fps, is 1/96sec.
At 90deg its 1/192 sec.
At 60fps, 180deg=1/120sec,
90deg shutter is 1/240 sec.

 

[Jeremy Neish]

Formula for converting between the two. Wikipedia:
http://en.wikipedia.org/wiki/Shutter_speed (near the bottom)

 

[David Battistella]

Two things would have to happen.

Shoot at 48fps
Project at 48fps

This was the original plan for film, BUT double the cost for aquisition, double the cost for distribution.

It might be possible for digital distribution, but let's not forget how much LIGHT you need to add to be able to aquire the same quality of image. You need a FULL STOP of light to be added at 48 and two stops for 60FPS.

That is a large amount of wattage.

David

 

[Stuart English]

Exposure at 48 fps

Exposure at 48 fps

But if you maintained close to 1/48th sec exposure per frame your lighting needs are the same.. no?

 

[Martin Weiss]

You need a FULL STOP of light to be added at 48 and two stops for 60FPS.

...or a camera with twice the sensitivity.

800 is still a bit more than 320 plus an extra stop.

 

[Rick Burnett]

No, I am not describing a 360 degree limit, I am describing the time that an active row of pixels has to be read out. If it takes 8ms for a complete read/reset, then each line I imagine could be off for 8ms/2540 (assuming max horizontal lines on the sensor) so that would be 3.14uS. Given 1/48 = 20.883mS, I think it's pretty safe to assume they are just rounding off since 3.14us would be a loss of .01% of time in that frame for the exposure which is damn close enough for me Hadn't done the math before, but now it makes sense.

 

[Jeremy Neish]

But if you maintained close to 1/48th sec exposure per frame your lighting needs are the same.. no?

True, but you'd have double the motion blur per unit of time due to the 360 degree shutter. Unless I'm calculating this wrong...

 

[Rick Burnett]

True, but you'd have double the motion blur per unit of time due to the 360 degree shutter. Unless I'm calculating this wrong...

Yeah, I am confused about this as well.

If you are shooting 48fps 1/48 then each frame is equivalent in exposure length to 24fps 1/48, you just have an extra frame for that other 1/48 that you ignored at 24fps.

 

[Roberto Lequeux]

True, but you'd have double the motion blur per unit of time due to the 360 degree shutter. Unless I'm calculating this wrong...

...or a camera with twice the sensitivity.

800 is still a bit more than 320 plus an extra stop.

It might be possible for digital distribution, but let's not forget how much LIGHT you need to add to be able to aquire the same quality of image. You need a FULL STOP of light to be added at 48 and two stops for 60FPS.

That is a large amount of wattage.

David

No, if you shoot 1/48th 48fps you need the same exact amount of light and have the same exact amount of blur, as if you where shooting the "standard" 24fps 180 degree (1/48th). The only difference in exposure time will be that which Rick calculated, which is negligible, especially on something capable of such high framerates.

All you have to do is drop your footage into an 24fps timeline in a decent NLE, and compress your clips to exactly half their durations.

You would want to shoot 47.952 for 23.976 if possible.

 

[Rick Burnett]

Not sure how well this will translate, but this is how I think of it, you shoot 24fps 1/48, and a ball is moving across your screen fast enough, the ball with be blurred but will also jump in location due to 1/48th of time being ignored by the sensor:

If you shoot at 48fps with 1/48, an additional frame is added to capture that ball in that period where the sensor is off.

If you could play back at 48fps, I would imagine a MUCH smoother movement for very fast objects as there isn't a period where the sensor is ignoring information.

But, if you wanted 24fps, 1/48, you can just drop every other frame and have EXACTLY what you'd have if you had shot it that way to beging with (minus the read/reset that you lose)

 

[Hrvoje Simic]

is the "videoish" feel of high frame rates built in or developed?

If by "videoish" you mean "not cinematic/not as good" - it's developed (IMO).


In our minds frame rate has been subconsciously connected to the type of content, and mental "habits" are not easy to change. If it's not 24, it's "not cinematic". Feels that way at the moment until we learn to allow other options and give them time to grow on us.
"Only 24 fps = cinematic = good" is something I'm pretty sure cinematographers of the future will laugh at.

 

[Roberto Lequeux]

Hrvoje, I agree. We seem as a society to have a big appetite for "reality", in every sense. EDIT: A good direction, so long as we continue to become more and more discerning in every way.

Maybe over-sharpened 48/60fps measured-4k 3D (or holographic!) is what we end up with for "TV" and films will just be softer, not over sharpened, plus better lighting, etc, etc, etc, etc, etc, etc, etc...

 

[chrislancaster]

if you want a good idea of what 360 shutter looks like on a cinematic movie watch the 2nd half of 2012

 

[David Battistella]

But if you maintained close to 1/48th sec exposure per frame your lighting needs are the same.. no?

You would have to open up one stop.

Take the RED for example:

24 FPS at 1/48th of a second is normal

If you used variable frame rates and went to RELATIVE:

The Shutter is locked so at 48fps you'd need to open up the iris to get the same exposure as 24@ 1/48th.

If you went to NORMAL mode, the RED Camera would compensate by controlling the shutter and leave the Iris fixed.


David

 

[Michael Hastings]

You would want to shoot 47.952 for 23.976 if possible.

Ha! You answered my next question before I got to ask it: and so presumably 59.94 for 29.97?

Stuart: Will these be standard rates on epic?

If by "videoish" you mean "not cinematic/not as good" - it's developed (IMO).


In our minds frame rate has been subconsciously connected to the type of content, and mental "habits" are not easy to change. If it's not 24, it's "not cinematic". Feels that way at the moment until we learn to allow other options and give them time to grow on us.
"Only 24 fps = cinematic = good" is something I'm pretty sure cinematographers of the future will laugh at.

Hrvoje: that has been my unscientific gut feeling for a long time. In the analog Betacam days (;-) I wrote 7-d but I meant Betacam) video had a distinct look far from the smooth, high DR look of film, and I believe the deep dof and interlace plus the overall "electric" look of video became associated with 30fps and the film look was associated with low frame rates.

However, I believe a transition was begun once cameras went digital and you could more easily adjust gamma, knee, and such plus some better color processing to make it more "filmic". Then in the last ten years or so extensive color grading became so prevalent that it often really is hard to tell with certainty which is which. So I think the "deprogramming" has already begun and it is being accelerated by cameras like the R1, and even dSLRs which (as much as we rail against line skipping/half assed resolution and moire) do tend to have a comparatively "filmic" look in terms of DOF, DR and color response.