Scaling 1080 down to 720 question, hmc150

F

firehawk

Veteran
I know that the HMC 150 achieves 1080 by spatial offset (pixel shifting) and therefore only resolves a little more detail shooting in 1080P than shooting in 720P rather than full native 1080 sharpness. But since it does resolve a little more detail would a project destined for 720P look a little better if shot in 1080P and then scaled back to 720P, rather than just shooting it in 720P in the first place?

EDIT: By scaling down, I mean scaling it back 68% on the timeline, editing the 1080 footage on a 720 sequence timeline. Or editing the whole thing in 1080 and then downcoverting it upon final export to 720.

Also...On a related note: would it be best to shoot a chroma key project in 1080P rather than 720P if destined for 720 in the end, for the same reason?
 
Last edited:
My theory is the less processing the better. stay in 720p
chroma keying: more uncompressed the better. plus, closest to 4:2:2 the better.
 
My own personal thinking is that it may not make much difference either way. The camera starts with a 1920x1080 image. If you record it as 1920x1080, then scale it down it becomes 1280x720. If you scale it in the camera it becomes 1280x720 anyway.

While I've never done that experiment on an HMC150, in playing around with scaling videos I don't notice any real difference pre or post scaling. Maybe there is a difference, but you would have to look at the pixel level, but if I can't see it while looking for it, I doubt anyone else could.


Bob Diaz
 
In my experience, images downscaled from a higher resolution often look better than those shot natively at the lower resolution. Granted, it's a difference which is more stark going from an HD resolution to SD, but fruit is borne from 1080p down to 720p as well.

Obviously, take your camera and experiment. See what you get.
 
MadHMC150 said:
I agree here, usually shoot 1080 all the time and export as 720.. unless I need 60fps.
Click to expand...

That's what I've been doing (unless I need 60fps, then I obviously have to either use a different camera or shoot 720) and it seems to work out pretty well.
I just wanted to check with more knowledgeable people.

Thank you
 
The best answer is to test and see what you think - but I shot with the 150 for a couple years and always shot 1080 unless I needed slowmo. It's very cool to be able to re-frame a 720p project, especially for things like interviews where you can hide a cut by having a tighter shot, etc. Reframing is huge, and having 1080 footage in your library if months from now you recall a background plate or something - that's good to have.

For keying, I did a massive keyed project with the 150 and did it all at 1080 for a 720 edit. The keys and final comps look much, much tighter when scaled down. It's one of those things that seems to help visually "glue" a comp together even more for some reason - grain structure gets more universal, and the bit of extra res. when pulling your key is very helpful. Especially with the 150, which isn't a phenomenal camera to key with.

I'd also throw in that for keying with the 150 - try to shoot daylight, try to be at f5.6 or so, watch your focus like a hawk, and throw a lot of light at the subject. Do a test with your screen lit at several levels to see which IRE your keyer prefers on the green.
 
You must log in or register to reply here.
Back
Top