I would like to create a background/backdrop for a video, but I am having quite a hard time deciding on the best dimensions for the backdrop. I will be shooting at 3840 x 2160. Is there a way to determine the dimensions based on the resolution? The idea would be to have a backdrop that completeoly 'fills' the frame of the camera, if that makes sense.
I tried playing with different options in Photoshop and Illustrator. i.e. I created a document with the dimensions 3840 x 2160 at 300DPI (since it's for print), determined it would come out as roughly 32.51 x 18.29cm, and then multiplied until I got a reasonable set of dimensions (i.e. multiplying 8 times = 260.8 x 146.32cm). But somehow, it seems wrong because I would need to place the camera at a certain distance from the background to capture it all.
I'm quite sure there's no rule or anything like that for this, but I would really appreciate any help/pointers on this one!