Why Does Higher Frame Rate Mean Smaller Frame Size?

[Tom Fox]

Presumably because more frames = more data

[Keith Koby]

Has nothing to do with FCPX… It’s bandwidth on the recording medium. It’s the same in broadcast. think about cable and sat too. 720p is 60 fps while 1080i is 60 fields per a second (30 frames per second). In order to push the resolution, you sacrifice frame rate and vice versa. The particular camera you are talking about has a limitation on either its processing power or recording medium bandwidth that restricts it from being able to record 1080p 50 for example.

Keith

Keith Koby
Sr. Director Post-Production Engineering
iNDEMAND
Howard TV!/Movies On Demand/iNDEMAND Pay-Per-View/iNDEMAND 3D

[Shane Ross]

It’s not cropped…that’s just the standard. 720p, as mentioned, is a 60fps or 50fps medium. 1080i is a 25 or 30fps medium (some 24fps on occasion).

1080p50…1080p60…VERY rare, only available on some cameras designed to shoot it…and not a standard for viewing. BluRay is 24, 25 or 30fps…TV is 25 or 30fps. The web doesn’t really do 60 or 50fps at 1080. It CAN, but it’s very rare. The main reason for using 1080p50 or 60 is to shoot footage you intend to slow down to 30, 25 or 24fps.

Shane
Little Frog Post
Read my blog, Little Frog in High Def

[Ben Mullins]

Hi,

Thank you all for your responses. My main reason for shooting at 50fps is as Shane says for slow motion. I use a Panasonic GH3 which allows 1080p 50 fps but reduces the data rate from 72Mbps to 50Mbps. Previously I had shot on a RED One and noticed that 50fps would reduce the frame size to 720 and I was just curious as to why some cameras might do this (a colleague uses a 5D and mentioned the same thing).

Thanks,

Ben.