ARRI Forum

Could you please clarify the topic below, explaining technically why is it better to shoot full HD instead of 2k (considering full hd output)?


Should I shoot ProRes HD or ProRes 2K?

For an HD deliverable, ProRes HD is best. Shooting ProRes 2K and down sampling to HD in post will not get you any resolution advantage, on the contrary, it may look worse than shooting ProRes HD in-camera. However, if you need to do some reframing, resizing, rotating or stabilizing in post, you could shoot ProRes 2K and then crop in post to HD. For that you would have to create some custom frameline so you see the original HD inside the 2K frame. While the ProRes 2K and the HD use a slightly different downscale factor inside the camera, we have conducted extensive tests that showed neither a difference in MTF nor a visible difference between shooting HD and shooting 2K with a crop to HD.
For a theatrical 2K deliverable, ProRes 2K is best as it is designed for a 2K cine post workflow.

Hi Melflores,

besides the fact that for 2K and HD a slightly different source resolution is being used to have an even downscale (general rule: the better the factors, the better the scaler, the better the result), there's no gain is downscaling twice, hence the saying in the FAQ.

In ALEXA
HD:
2880x1620 > divide by 1.5 > 1920x1080

2K:
2868x1614 > divide by 1.4 > 2048x1152

2K to HD:
2048x1152 > divide by 1.06666 > 1920x1080


Cheers,
Jan