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Bruce Dempsey September 10th, 2014 05:00 PM

120p all the time
 
If you cam can do it why not shoot 120p all the time not just for slomo? Afterall if 60p is better than 30p for action wouldn't 120p be even better?

Noa Put September 10th, 2014 05:03 PM

Re: 120p all the time
 
I think the problem would be to find a player and tv that was able to display at that framererate, in real life that would mean you would have to convert to 25p/50p anyway making it only usefull if you would use it for slowmotions.

Bruce Dempsey September 10th, 2014 05:06 PM

Re: 120p all the time
 
Talking aquisition Noa. It would of course be deliveredat regular frame rates.
My point is Would there not be more detail at 120p thus better video?

Jody Arnott September 10th, 2014 05:24 PM

Re: 120p all the time
 
Quote:

Originally Posted by Bruce Dempsey (Post 1860919)
Talking aquisition Noa. It would of course be deliveredat regular frame rates.
My point is Would there not be more detail at 120p thus better video?

I'm not sure there would be more detail at 120 fps? The resolution is the same, just more frames.

I think low light would suffer too as you'd need to use a higher shutter speed.

Bruce Dempsey September 10th, 2014 05:41 PM

Re: 120p all the time
 
120 pictures per second is bound to reveal more detail in movement than 60 or 30 pictures per second
Oh Yeah more light needed for sure

Chris Medico September 10th, 2014 05:43 PM

Re: 120p all the time
 
And it will take more space on the recording device as well.

Bruce Dempsey September 10th, 2014 05:53 PM

Re: 120p all the time
 
that depends if the datarate goes up because 50 Mb/s wehther 120 frames /s or 15fps is still 50 Mb/s and would take similar memorycard space..So I guess the overall quality of the video won't improve with higher frame rates unless the bitrate goes up to because you spread the bitrate over the second regardless of framrate
movement will be smoother with higher fps and maybe that translates to percieved better video?

Brian Drysdale September 11th, 2014 09:55 AM

Re: 120p all the time
 
Apart from slow motion, there's no point in shooting at higher frame rates unless you intend to project at those frame rates. Douglas Trumbull is a big proponent of high frame rate production and exhibition . Home | Douglas Trumbull - Immersive Media and Visual Effects Tests seem to indicate that there's little gain beyond 60fps.

Screen brightness is also important.

At high frame rates like 120fps you have a fast shutter speed, which means that when played at the standard frame rates for normal speed action, you'll have strobby type effects similar to "Saving Private Ryan. Shooting at the slower, standard frame rates and standard shutter speeds you have blurring which smooths out the action.

Chris Medico September 11th, 2014 09:58 AM

Re: 120p all the time
 
That does assume that you drop frames to get down to 24 or 60 or whatever. There is an interesting approach that actually combines the frames instead of dropping them. That doesn't render out looking like Saving Private Ryan.

Not that I would suggest shooting 120fps for everything though.

Noa Put September 11th, 2014 10:17 AM

Re: 120p all the time
 
Quote:

Originally Posted by Bruce Dempsey (Post 1860919)
My point is Would there not be more detail at 120p thus better video?

No, you only get more frames, not more detail.

Brian Drysdale September 11th, 2014 11:22 AM

Re: 120p all the time
 
Quote:

Originally Posted by Chris Medico (Post 1861018)
That does assume that you drop frames to get down to 24 or 60 or whatever. There is an interesting approach that actually combines the frames instead of dropping them. That doesn't render out looking like Saving Private Ryan.

Isn't the net effect of that a recreated motion blur in post?

Chris Medico September 11th, 2014 11:50 AM

Re: 120p all the time
 
Exactly. It eliminates the stroby look of the high shutter speed. It looks natural and not processed as if you were using a motion blur effect in post. So if you want to shoot 120 you can and still bring it down to a lower frame rate that looks natural.

Even so, I don't recommend shooting that high day in and day out.

Bruce Dempsey September 11th, 2014 12:04 PM

Re: 120p all the time
 
just now compared 1280 120p xavc-s 50mbit to 60p 1920xavc-s 50mbit same static shot same light and 60p is prettier by a considerable margin and the ax100 won't default to 120p upon boot which tells me something too
maybe 1920 at 120fps or someday 3840 at 120fps whoa

Noa Put September 11th, 2014 01:04 PM

Re: 120p all the time
 
And if you would compare 4k at 25p that would even look more detailed, like I said before, framerate has nothing to do with the detail, you did compare 1080p with 720p, ofcourse 1080p will be more detailled, no matter what the framerate is.

David Heath September 13th, 2014 06:39 PM

Re: 120p all the time
 
Quote:

Originally Posted by Bruce Dempsey (Post 1860919)
Talking aquisition Noa. It would of course be deliveredat regular frame rates.

But then it would either be at half speed (assuming "regular" = 60fps), or you'd have to drop every other frame. If the latter, easier to simply shoot with a shorter exposure time per frame. When each frame would have less motion blur - so be sharper - but this can cause a "jerkiness" to motion.

To change the motion rendition, you'd have to shoot and show both at 120fps. (And there are advocates for doing just that for future systems.)
Quote:

My point is Would there not be more detail at 120p thus better video?
There may be LESS detail, it depends on the camera. As example, take the FS700. It has to simplify sensor readout at 120fps, so drops lines when it reads the chip. Hence a 120fps frame is worse quality than one at 60fps - you can see that in Adam Wilts review at - High Speed and Low Light with the NEX-FS700 by Adam Wilt - look at the charts at the bottom.

In the case of the second one (for 240 and 120 fps) the resolution has been halved on each axis and there's vastly more aliasing compared to the 60fps chart.

I suspect most cameras will have very similar issues - full uncompromised full sensor readout at 120fps would be pretty difficult.


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