I wonder if anyone can help me with an issue I'm currently having in post for a project where some of it was shot at 90fps.
The project is a music promo and the idea was to have some footage shot at 100fps which we could then ramp between slo motion and standard speed by increasing the rate to 400% in FCP (using rendered Pro Res files). I have done this before on other projects successfully.
The issue I have is that due to a circumstance on set the rushes intended to be shot at 100fps have been shot at 90fps instead. They play back fine when playing standardly over 25fps as slo motion. The problem I have is ramping the footage back up to a standard speed.
After working out (perhaps incorrectly!) that the footage should be sped up by a rate of 360% it synchs up correctly to the track. I have, however, some ghosting on the image. I have had this before when working with the 100fps footage at 400% but checking the speed is correct and then rendering would get rid of this. With the 90fps footage it is staying ghosted, and is the crux of the problem I have.
I am guessing that I either have the % increase necessary wrong or that there is some other inherant issue trying to do this with 90fps footage due to the fact that it isn't easily divisible into 25fps.
If anyone has had experience of this or could help me out that would be fantastic.
360% is correct. The ghosting you're experiencing is a FCP problem, but you can alleviate it by selecting the clip, pressing CMD+J and unchecking 'Frame Blending'. Frame blending is more useful when you're slowing down clips.
The best option however is to do the speed ramping in something like Motion or After Effects. You have a lot more control.