50p, 25p, 100th v 50th?

[Ian Chapman]

I mainly shoot with Canon XF300's (up to four) at 25p with shutter speed set to 50th sec.
My editing is therefore done on a 1080p timeline.

I have added a Panasonic FZ2000 for some 4k footage, but mostly for high speed (slow mo) shooting for short clips of fast action to be inserted here and there.

When I choose the frame rate on the various preset options available on the FZ2000 (up to 120pfs) it plays back in nice slow mo within my standard timeline. No issues.

However, I have experimented with shooting in 50p (up to 200mbp is available ALl intra) to gain higher quality on the slow motion.

Should I shoot the 50p footage at 100th sec (as people seem to advise i.e. double frame rate) or keep it at 50th to match the 25p?

I ask because initial observations show some motion blur effects when I render out to 25p MP4 having set the 50p footage to a higher shutter speed (100th)

What's the best way to achieve higher quality slow motion from the 50p footage clips but still have them play back smoothly?

thanks. Ian

[Rainer Listing]

If you want the same amount of motion blur you have to have same shutter speed regardless of the frame rate, e.g. 50fps viewed at 25fps to look like 25fps has to be captured at the same frame rate as the 25fps - in your example 1/50th second. But don't obsess about it - the twice frame rate "rule" is just a rule of thumb. Like you said, you might be getting sufficient pleasing motion blur at half the shutter speed.

[Cary Knoop]

I think the rule is important for 24p and 25p, it is somewhat less so for 30p.

When you go to 50p and up it does not matter too much.

For slow motion I would maintain the same shutter angle, e.g. 50p -> 25p use 50p = 1/100.

[Paul Kellett]

Interesting thread regarding the same issue.

http://www.dvinfo.net/forum/open-dv-...speed-60p.html

Paul.