GH5 - Aggressively Crushed Blacks?

[Cliff Totten]

So I have spent the weekend shooting my backyard with my new GH5. I gotta say that I do love this camera but one thing I have noticed is that no matter what gamma profile you use, this thing REALLY crushes it's backs.

It just seems that grays and dark grays fall off OK but then, suddenly, the GH5 dips the darker blacks STRAIGHT down way too early. It literally falls off a Cliff. V-LOG seems to hold the low end better but any other profile slams the crap out of the shadows.

Maybe this is just the "Panasonic look" or something. Anybody else notice this with their GH5?

Is is possible that Panasonic is protecting the highlights of the sensor by sacrificing the low end by mapping the sensor gamma readout like this?

CT

[Phil Lee]

Hi

Are you sure it isn't a level issue? Are you recording 0-255 or 16-235?

I've noticed nothing untoward with the black levels, however there are options to change these in the video settings menu.

Regards

Phil

[Simon Denny]

Cliff, did you ever resolve the crushed blacks, I'm finding the same however I have just migrated from Sony so maybe I'm seeing things.

[Phil Lee]

Hi

Are you recording as 0-255 or 16-235? Do the crushed blacks appear when played back from the device to the monitor or just on a PC/TV? What picture profile are you recording in?

Regards

Phil

[Simon Denny]

Hi Phil, I'm using 0-255 and also just discovered 0-1023. Wish there was more detailed info on these settings and how to use them accordingly. It just looks like the low end is crushing more than I'm use to. How am I determine this, via HDMI to my Flanders monitor and looking at wave/vector guides.

Also I love taking stills and noticing the blacks are heavy in JPEGs. I need more time to setup the camera and explore.

[Phil Lee]

Hi

Try video as 16 to 235 which is the standard for video.


With 0-255 then black levels below 16 can be crushed if playback codecs are treating it as video level. This shouldn't affect photos though.

Regards

Phil

[Simon Denny]

I'm not sure I understand these settings for luminance levels with Record Format choice.

In the Record Format MP4 (LPCM) 422/10bit 0-255 up to 16-255

In Record Format MOV 422/10bit 0-1023 to 64-1023

I recall Avid having to deal with luminance issues however I'm now in PP. Seems like most people use 0-255 however no MOV 0-255? unless it's 420/8bit.

[Ron Evans]

Video levels at 8 bit will be 16 to 235 and for 10 bit 64 to 940. If you shoot to 0 on either then edit and playback in a video timeline the blacks will be crushed because everything shot below the limits will be black. Anything above the limits will exceed the legal upper limit. You can of course use the upper limit of 255 and 1023 and get super whites as do a lot of video cameras. It is a question of matching the source to the timeline parameters. If you go straight to a TV then below the limits will be crushed by default. At least that is my understanding and I have my GH5 set for 16 to 235 for UHD 60P

EDIT: full explanation here https://en.wikipedia.org/wiki/YUV

[Simon Denny]

Thanks Ron,

Lot of messed up info out there on this subject with this camera. 16-255 seems correct to me or 16-235.

[Phil Lee]

Hi

Video is 16-235, 16 is black and 235 is white, it's just the way video was when TV first came about as they need space either end for other things.

Computers are 0-255, and webcams and smaller MP4 cameras will usually record 0-255.

Computers however often have a setting for full colour range or video/limited range, so when they play video they expect 16-235, so stretch out 16-235 to 0-255, so black at 16 becomes proper black on a PC at 0 and the same for the white at the other end. If this isn't happening you can tell as often the video played back looks just like someone has turned the contrast down and it has a washed out appearance.

If the computer or playback device is getting 0-255 video but thinks it is 16-235, it stretches it again, but now of course all the black information that was in 0-16 is lost, and dark grey becomes black.

16-255 often looks okay, but because whites are above 235, these are often referred to as illegal whites or superwhites, and typically get lost on TVs, as they stretch 235 upwards and anything above that is clipped or lost.

16-235 is likely the safest option as editing packages and most media players etc expect this, although some media players will get it wrong still.

Recording 0-255 has advantages. You get 255 shades of grey (or other colours), rather than 219, and in total can capture a much large range of colours. The negatives of course is if the playback device is a TV, it's not going to look right. So why have that option? Well for those editing their footage and in the know, you get more data to work with on the timeline for adjusting exposures or colour. Of course if the output is for playback on a TV, you need to export the footage compressed back into the correct range so it looks right.

Regards

Phil

[Simon Denny]

Thanks Phil, next stop for me, import into Avid.

[Simon Denny]

Two days of reading and extensive tests on using 0-255 v 16-235 I have come to the conclusion that I'll stick with 0-255 for now or if I have the GH5 setup incorrectly.

[Ron Evans]

You can always reconfigure the range in your NLE. It is just more work and if playing back directly to a TV the blacks will be crushed. The Superwhite may be fine though for most modern TV's

[Simon Denny]

Yep, this is what I'm trying too work out with, shoot, hand over to client etc.... As an editor I understand the the different flavours 0-255 v 16-235, it's the client side that I need a foolproof workflow. Some client editors don't care or don't know as I have seen with my own stuff later on TV.

I also need to be mindful with the different NLE's in particular Avid and PP which I work across along with clients, the client side needs to be a seamless effort.

[Ron Evans]

If you want to be sure the client will not get confused then stay with 16-235. Fanatics can get a little more from 0-255 but at least if you deliver 16-235 none will complain about crushed blacks or superwhites.