disadvantage of filming in 50p editing 25p

Shutter speed does not affect the motion nearly as much as frame rate does.

Frame rate is about the number of pictures taken per second. When a lot of pictures are taken per second, then anything moving does not move very much between pictures. When fewer pictures are taken, then they move more -- seem to "jump" more from picture to picture -- than at a higher frame rate. This gives a particular flavor to the motion.

A shutter speed is the length of exposure. All it affects is the apparent blur of moving objects in each individual picture. It doesn't change how far an object moves from picture to picture. A very fast shutter speed can produce more of a staccato motion -- make it seem jumpier -- but that effect is quite mild compared to the frame rate. And the same shutter speed will give you very different effects when used at different frame rates.

The difference between 50p and 25p, visually, is that 50p looks "live." It looks "live" because the motion is very close to what you see in real life. 25p looks more surreal, more "fictional," because the motion is not what you see in real life.

50p at the same shutter speed as 25p will still look a lot more "live" than 25p will. The overall flavor of the motions is the same; the shutter speed just adds seasoning. And just like seasoning has different effects on different flavors, so, too, does shutter speed on different frame rates. But a steak still tastes like a steak, and not chicken, if you put "cajun chicken" seasoning on it.

A lot of this is demonstrated -- especially the shutter speed differences -- in the demo reel of the 24p & Frame Rates tutorial. You can download it (you must watch it at 60p, and web services don't display at that rate, so it must be downloaded) at the page here:

http://www.wrightsvillebeachstudios.com/24pFR.html

Or directly here:

http://www.wrightsvillebeachstudios.com/24pExpts.zip
 
egproductions said:
In regards to pulling 24P from 60P footage, that is not recommended. You can't do an even pull down with those frame rates. In NTSC world you would have to shoot at 120FPS to do a 24P pulldown.
Click to expand...

If you shot correctly, converting from 60p to 24p is 99.9% indistinguishable from something shot natively at 24p. The "pulldown" difference is identical to viewing 24 fps material in a 60 stream with 2:3 pulldown, and that has been done for many decades, every time a movie is shown on TV. It is not a problem.

Reasons you don't want to make a habit of it are that it costs you a generation to make the conversion, and because you can't effectively monitor your motion while you're shooting 60p. When you convert to 24p, you will end up with footage with the same motion it would have had if you had shot 24p all along, so if you moved the camera too quickly, you'll end up with the exact same exaggerated strobe. Better to see what you're doing all along.

Also, converting to 24p from 60i costs you some vertical resolution, but that's not a concern with 60p. And with most current camera systems, shooting 24p natively gives you longer recording times than shooting 60p.
 
If I understand the original question correctly it wasn't about wether 50P will look different than 25P but rather if 25P extracted from 50P will looking different than if the video was just shot at 25P to begin with. To which my answer would be no, assuming you used the same shutter speed.

David, its funny that you mention that a 24P conversion from 60P can be indistingushable from shooting 24P originally. You make a good point with the 2:3 pulldown, however the only reason I thought it was a bad idea is because of an answer you gave me to the post a little while back. Your words:

"...120 fps would actually be better than 60 for conversion to 24, because it's an even 5:1 ratio -- leaving whole, non-interpolated frames -- instead of 2.5:1, requiring either interpolation or a slight cadence change."

Not trying to call you a hypocrite by any means. Your 2:3 pulldown approach clarified an assumption I was making.
 
I don't think that's all I said, though. :) I definitely didn't say converting 60p to 24p wasn't recommended. 120 fps would be a smidgen cleaner, but doing it from 60 is fine.
 
I bought David's frame rate tutorial and I'm glad I did. I have Sony Vegas (not pro) and also had to purchase this....

http://www.dvfilm.com/maker/

...in order to get true 24P to edit (from DVX100A in 24P-Advanced mode), but thanks to the tutorial I know how and why to use it.
 
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