Blackmagic Forum

Hello everyone,

I've been training of Resolve 18 for quite a bit so far, and I have encountered my first issue today.

I own an Fx3 and I Record all my shots in S-Gamut3.Cine/S-Log-3.

When exposing in the camera I am pretty sure I exposed correctly, however, when I Use the color space transform and I set the input colorspace to Sony S-Gamut3.Cine and the input Gamma to S-Log-3, I am faced with an underexposed clip. This has been happening all the time and I have 0 clue on how to fix it.







Your support Is highly appreciated

What happens if you use Resolve Color Management rather than a CST node?

I don't know what you are targeting as correct exposure in that scene but exposing on log requires specific knowledge and tools. If you use false color it's middle grey needs to be set at the correct range on the signal.
https://pro.sony/s3/cms-static-content/ ... 271406.pdf
According to the paper SLog3 has mid grey at 420 for 10bit.

The other part you may want to check is what your timeline colorspace is set to. (probably Rec.709 (scene) instead of Rec.709 Gamma 2.4).

It's actually better to not pick 'use timeline' for CSTs because that breaks anyway when you want to set your working space to log for colorspace aware grading. Set the CST manually to Rec.709 Gamma 2.4 and keep Apply Forward OOTF checked. Then set your timeline colorspace to SGamut3.cine/SLog3 and voila, you're grading scene referred without project wide color managed mode.

If you'd want to grade in DaVinci Wide Gamut instead or any other space set it to that instead but that requires your footage to be converted to it too as the first node otherwise the color tools aren't colorspace aware anymore.

There is no law that says you have to use the specific gamma space for decoding. You can work in display-referred, using scopes and an external calibrated display, and make your contrast / brightness decisions based on that.

Usually with Blackmagic cameras, I lean towards decoding in Blackmagic Film Gamma, which gives me kind of an Arri LogC feel. I can manually adjust from that pretty easily and get totally acceptable results. I would bet you could do the same thing with the SLog clips. What specific Sony camera are you using? Is it 8-bit or 10-bit color depth? (Info available on the Media Page.)

Please tell me you found a solution for this, I’ve having the same issue as you, OP

Can you post a short sample to a cloud service?

Pureguavaa wrote:Please tell me you found a solution for this, I’ve having the same issue as you, OP

The OPs use of CSTs is incorrect. If you are mimicking those settings you will get an incorrect result. If you can do as Uli suggests and post a short sample (a Resolve archive with media), someone can take a look.

laithsh wrote:Your support Is highly appreciated

For once, I'll agree with Jim Simon: introducing CSTs when you really don't know what you're doing is going to cause you grief. And whatever advantage a CST workflow might present is tiny (or more likely negative) for a beginner, compared to color management where these decisions are made for you.

You're also going to find it harder to grade in a log color space, which is a good reason to set rec. 709 2.4 instead. The advantages of doing otherwise are not going to be apparent to a beginner, and results are likely to be worse.

Set up Resolve Color Management, even using the simplified defaults, and see what you get.