Hi,
And here, so far, I have been very happy, smugly reading the posts on frame rate issues and thinking to myself - "I am so glad I live in PAL country - Shoot 25FPS, playback 25FPS, no funny "So-called" Drop Frames or, how do you say it... "Pull Down" to worry about".
Sigh
We have signed up to a stock footage firm, and hope to use them to source a lot of our aerial and panoramic nature shots and...you guessed it... they come in either 23.976FPS or 29.97FPS flavour.
I had a heart attack this morning, and almost blurted out my ignorance on the forums, because I imported some 4K footage (at 29.97FPS) into my 1080p 25FPS After Effects comp - the footage is of a fast pan accross some mountain passes. When I played it back, there was a terrible "Judder" and my heart sank. My first impression was that there was an issue with 4K footage in a 1080p project 
Thankfully I took some advice seen a few times on the firums from Dave - I sat back, took a deep breath, let it out.....and did it again.! 
Once I thought it through, it occured to me that the frame rates were different, and after a few tests using comps of different frame rates, I could prove that this was indeed the issue. I have now spent some time looking up frame rate conversions, and it looks to me that I am sitting at the wrong end of the Frame Rate Spectrum.
Am I correct in saying that it is easier to convert from 25FPS to 29.97, rather than the other way around? So far, the best information I could glean from the sites I went to (and most of this is from comments posted by Dave) is that Twixtor should do a fine job at assisting in the conversions.
I have recently bought Twixtor, so I am busy running a few tests to see whats what.
I thought I would take this chance to have a chat about frame rate conversions, and see if there are any new improvements and suggestions on going about this. As can be seen from my comments above, to date, I have not had to deal with Drop Frames or 3:2 Pull downs, so I need to start from scratch learning about them. I will be doing some heavy reading in the next few days, but any other advice would be appreciated.
Twixtor.....its you and me now........
Pierre