Z150 and Z90: are they recording Hybrid-Log Gamma in 8 bit?

W

wilecoyote

Member
Hello:

I've been looking at specs for the Sony Z150 and Z90, since I'm looking for camcorders that can record HDR and their Hybrid-Log Gamma support was something that appealed to me. However, once I've started digging into the specs page, I found this (from https://www.bhphotovideo.com/c/product/1222976-REG/sony_pxw_z150_4k_xdcam_camcorder.html):


Color Sampling:
XAVC Long
4K: 4:2:0 8-bit
HD: 4:2:2 10-bit
Click to expand...

In other words: when in 4K, the Z150 (and the Z90 too, I presume) can record HLG... but only in 8 bits.

An HDR format like Hybrid-Log Gamma, recorded in only 8 bits? What?????

Alistair Chapman mentioned explicitly in http://www.xdcam-user.com/2017/07/what-is-hlg-and-what-is-it-supposed-to-be-used-for/ :

HLG was designed for 10 bit distribution using HEVC, it was never meant to be used with 8 bit codecs, so be very, very careful if using it in UHD with the FS5 as this is only 8 bit.
Click to expand...


I can only ask: has anyone actually tried it? (Shoot 4K in HLG and view it in a HDR device, that is). Are the results... acceptable at all?
 
You are correct on all counts. The cameras all have S-LOG so if you are going to record for HDR, that is what you should use instead of HLG. HLG is intended for "live" applications and not grading.
But of course, even if you use S-LOG you are still faced with 8-bit, so these are not really cameras that you would want to use for 4K HDR of any kind.
 
Here are some 10 bit 4:2:2 HLG 720p/1080p HLG clips converted to PQ (HDR10) shot on the Z90. The only device I have that can play them back at full 1000 nit is my Samsung Galaxy S8 phone.

I am noticing that in HLG mode, my shadow noise worse, very noticeable in HDR or REC709 outputs. I am most pleased by the increased saturation of things like blue, which really pops on the police lights in HDR10 BT2020 compared to REC709.

https://youtu.be/MCqZeB9FxCc

https://youtu.be/qH2F1HRB1k0

https://youtu.be/bpgqJQo7BU4

https://youtu.be/CbCr2u5ww14
 
Here is a n 8 bit 4:2:0 HLG 4K clip, converted to PQ (HDR10), as a comparison. The most noticeable difference in my footage that I see, is that the glowing color orbs around bright lights, are banded on the 8 bit footage, but smooth on the 10 bit HD clips.

https://youtu.be/2snfr1ocJhc
 
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