1:1 Crop mode (5x zoom) vs 3x3 binning ("normal") recording quality

[markodarko]

Hi guys and gals,

Since playing around with 1:1 crop mode a few weeks back I've been pseudo-obsessed with thinking about perhaps re-shooting the three short scenes I've done so far in my movie @ 2560x1072 (instead of the original 1920x804 that they were shot at) with the mind-logic that it should (surely) look better scaled down to 1080p rather than recording 1080p natively. Surely.

However, none of this was with any testing, just hypothetical logic in my ickle brain, so tonight I thought I'd try a quick and dirty shoot to test out the noise between 1:1 and 3x3 binning after A1ex's reply in this thread. It's clear to see at 3200 ISO that 5x zoom mode is decidedly more noisy. In fact, in contrast the 1920x804 non-crop image is very useable at 3200 ISO. Still plenty of detail.

Note: All I'm testing here is noise.

All I did with these shots were bring them into Resolve, add a Rec.709 color space and desaturate them to make them legal in the vectorscope:

1920x804 @ 3200 ISO on 1920 timeline


2560x1072 @ 3200 ISO scaled down to 1920 timeline


1920x804 @ 3200 ISO scaled up to 2560 timeline


2560x1072 @ 3200 ISO on 2560 timeline


1920x804 @ 3200 ISO scaled up to 4K timeline


2560x1072 @ 3200 ISO scaled up to 4K timeline


1920x804 @ 3200 ISO scaled up to 4K timeline (left corner)


2560x1072 @ 3200 ISO scaled up to 4K timeline (left corner)



Now, obviously there are differences in the setup of this test. Even though both times I focused on the nail varnish bottle (not mine, honest) there will be differences in the DOF as these tests were done using the same lens with me just moving back a bit to try and frame the shot the same as the non-crop image in 1:1 crop mode (mainly because I don't have a super-wide lens to get the same perspective in 1:1 crop). Not scientific at all.

If I was doing this scientifically (and if it wasn't so late now) then I'd use my 35mm lens for the 1:1 crop mode and then match that shot with a zoom lens at around the 100mm mark without moving the tripod etc. I may do that tomorrow if I've got time and add a selection of different ISOs into the mix too.

Right now though, at 3200, and with regards to noise, even with the different DOF it looks clear to me that the advantages the extra photons bring to the table in 3x3 binning mode ("normal" recording) far outweigh the extra pixels of the 5x zoom recording. Not just on the 1920 timeline but when upscaled to 4K too. It'll be interesting to see if that's the case at lower ISOs too.

Not rushing out to re-shoot that footage at the moment though...

[Ali Oliya]

cant see the pictures...