Hi,

in the next time i want to film some mountainbike/freeride action. I like the look of films like "the collective", "roam" or "ckd". I know that this films are 16mm. I want to get a similar look and so i would shot in 25f. But i dont know which would be the best shutter speed for this kind of action to get the most filmic look? I am greatful for every idea.

To emulate film, you generally want a shutter speed of 1/48th or 1/50th.

Some film cameras offer adjustable shutters, but none of the cams used in the films you mention do that trick. It's the newer film cameras (Arri 435, SR3, etc) that can shoot short shutter speeds.

Also, in order to do slow motion in the post, shoot in 60i and conform to 24f in the post. In that case, people recommend to shoot with 1/120 for crips look. Oh, I'm assuming that you will be shooting with XH G1/A1 or XL H1.