24p

[rmshkarthik]

hello, could u tell me.

24p it means 24 frame in cine format or other thinks, if. it is what is that? i feel very curious about to get clear lessson in 30i and 60i. in video camera how we can change the shutter angle. i have heard 1/250 shutter is egual to 45 degree shutter in film format for blur effect. i am using PAL format.

thanks

[Laurent Andrieux]

Cinema works at 24 fps. each frame is shot in the camera and then projected at this rate and each frame is projected during 1/48 s and the shutter is closed, allowing the next view to be track down in the gate during another 1/48 s.

 

Each frame is then exposed and projected at a 1/48 s time.

 

This rate shows flickering. In projection, there is a trick that is to project each frame in two times, the shutter being closed twice in a ctual cycle.

 

In video, another solution was found : the video image is recorded a lines that will further be traced on the monitor, from left to right and down to the bottom.

 

The idea is to project the image in 2 times as well, but first, only the odd lines (1, 3...) are projected, each line being recorded and then projected 1/60 s if you work at 30 fps (ntsc), or 1/50s if you work 25 fps Pal.

 

This is call interlacing of the frames/lines in video.

 

Since video camera manufacturers are setting up video systems for cinema, it became interesting to imagine a system that would provide 24 plein frames each second. The videio image is then made of all the lines and all the lines are projected at once, line after line, in progressive mode (line 1 then 2 etc...).

 

You then can easily - at least more easily than from 60i... - get a 35 mm print from a 24p video material if you want to 35 mm positive project and screen the film...

 

Does that make any sense and answer your question ?