GH4 & Stills: Does aspect ratio matter?

[acuriousman]

I've been hearing a lot of conflicting info about this.

Is there one aspect ratio for stills that will garner the best quality/dynamic range over all others? I've been hearing 4:3 is the best aspect ratio for stills because it "uses the entire GH4 sensor".

Is this true or will they all give you the exact same quality?

[leeys]

Yes, it's true. There's no more multi-aspect sensor since the GH3 so anything other than 4:3 involves a crop.

[JazzBox]

Are you sure? I ask because in video, more then often, using a crop of the sensor give a better quality (i.e. crop mode on Canon T3i/600D).
Why it is not true for GH4? It could be at least the same id not better. But I'm not a scientist, I suppose and I'm very curious about it, since I use a GH4

[Guest Ebrahim Saadawi]

The GH4 uses a 1:1 full sensor readout to produce the 4K video, it's nearly using the entire sensor, so you can just record that and crop later in post, like people in stills do (as their cameras record the full sensor too) 

 

But with cameras like the t3i, where the sensor is 6K while the output is 1080p, the camera skips many lines of resolution, throws them away to get to 1080p, while, with the crop mode, it can just take the center 1080p native window. In other words, in the crop mode it records entirely new pixels in the center that are skipped when you record the full sensor. In the crop mode it eliminates the aliasing/moire issues as no line-skipping occurs, but of course a tiny sensor give much deeper depth of field, and that tiny sensor aesthetic, noise is also amplified as line skip+compression takes away some of the noise...

 

But when you can record the entire sensor 1:1 anyway (GH4) it's better done in post, like stills people do it.

[JazzBox]

Thank you! I start to understand!