4K HD and 4K 16:9 difference

[PabloMCV]

Hello

Can you explain what is the difference between 4K HD and 4K 16:9

Sorry I don´t understan

Thanks

Pablo

[Eric Z]

One is 4096 x 2160 and the other is 3840 x 2160.

[Jarek Zabczynski]

Shouldn't they both be 16:9 though?

[Brandon Kraemer]

"4K" is no longer 16:9, 4K HD is. There used to be (RED ONE) both 4K HD and 4K 16:9 resolutions available. The difference was 4K HD was evenly divisible by 1920x1080 which made transcoding faster but both were 16:9 formats. Now on the Epic/Scarlet cameras 4K is 4096x2160 and has an aspect ratio slightly wider than 16:9, effectively 256:135. The 5k, 3k and 2k resolutions are also 256:135. To scale and fit height to say 1920x1080 you will crop information from the sides.

Does anyone know why there doesn't seem to be 2/3/4/5k resolutions that are 16:9 on the newer cameras?

[Brian Iannone]

4K: 4096x2160 (a.k.a. 2160p)
Aspect Ratio: 1.9:1
Used in cinema.

4K HD: 3840x2160 (a.k.a. Quad HD)
Aspect Ratio: 16/9 (1.78:1)
Used when the delivery format will be 1080p. 4K HD (QHD) is exactly four times larger than 1080p, so it resizes proportionally down to 1920x1080.

[D Fuller]

Hello

Can you explain what is the difference between 4K HD and 4K 16:9

A little history:

4K 16:9 was the original 16:9 resolution offered in the Red One. It is 4096x2304. It is not, at present, available in Epic/Scarlet. (I have no idea if it ever will be.)

4K HD is 3840 x 2160. It was developed to provide a setting that is sharper and less processor-intensive for downsampling to 1920 x 1080 HD. It is, as Brian says, "Quad HD" or exactly 2x the resolution of 1080HD in each dimension, so the math is simpler for the downconverter, resulting in better, faster downsampling (especially in programs like FCP that are not the best down-samplers on the planet). This resolution is available in Epic/Scarlet.

[Stuart English]

4K: 4096x2160 (a.k.a. 2160p)
Aspect Ratio: 1.9:1
Used in cinema.

4K HD: 3840x2160 (a.k.a. Quad HD)
Aspect Ratio: 16/9 (1.78:1)
Used when the delivery format will be 1080p. 4K HD (QHD) is exactly four times larger than 1080p, so it resizes proportionally down to 1920x1080.

Correct ...

[Uli Plank]

I suppose they dropped it for other sizes since for a delivery in HD 1080 it doesn't make much sense to use anything else but Quad HD.
You might say that you'd like 5K 16:9 for getting a bit wider from the same lens, but that's about all I can see as useful. In most other cases you'd shoot for multiple delivery formats anyway and would need to frame accordingly. BTW, 5K is great for re-framing in post, but then your original ratio doesn't matter that much.

[Chris McKechnie]

So if you're wanting to acquire in 5k but have a 1080p deliverable, what would be the ideal aspect ratio to not lose too much of what you're seeing on the monitor when recording?

[Bob Gruen]

Think of what happens to individual pixels when you scale down. In 4K HD a four pixel square is combined into one final pixel. This is not true of the other formats: when combining the 'edge' pixels have to be handled in terms of percentages. Think of 3K HD where 1.5 pixels in each direction get combined into one pixel. 5K HD is much more complex.

If final delivery is 1080p I think I'd shoot 4K HD, unless I needed a wider shot than my widest lens could deliver.

Bob