Log to Rec 709 questions

[macman4789]

Hi,

Bit of an amateur question, but if I’m recording in any log format (CLog2, Clog3, Slog, Apple log from an iPhone), if I then get the conversion LUT for that respective log form from the manufacturer to convert to Rec 709, in theory should they all look identical? Or would you see some major differences because of the way certain brands produce certain aspects such as skin tones etc?

I’m trying to know the best way of matching up say iPhone log footage and CLog 3 footage so they look as close as possible together.

Secondly, similar question, if I recorded in Apple Log and then recorded on another device in Apple Log 2, but then converted both to Rec 709, would they both look the same?

Many thanks

 

[lin2log]

No, they would most definitely NOT look identical just becasue of some LUT. Just as two NO-LOG cameras wouldn't. Different sensors = different color science.

And recording with the wrong LUT relative to the SENSOR will most definitely not help anything either. Then you have to differentiate between CAMERA LUT and CUSTOM LUT, too! Those are two entirely different things.

Bottom line: if you're converting/viewing/editing in 709, why even record in LOG to begin with?? 🤨

 

[smithdr]

"I’m trying to know the best way of matching up say iPhone log footage and CLog 3 footage so they look as close as possible together."

The best way to get log footage to look the same is to grade in a common gamut. In Davinci Resolve, that common format can either be Davinci Wide Gamut or ACES. This is done via a color space transform (CST) node. Not certain how to do that in FCP.

"Bottom line: if you're converting/viewing/editing in 709, why even record in LOG to begin with??"

One records in Log to get more dynamic range in the final graded result prior to converting to Rec. 709. Again, in Davinci Resolve this is done with a CST node that converts from Davinci Wide Gamut to Rec 709.

Hope this helps.

Don

 

[ChrisA]

I’m trying to know the best way of matching up say iPhone log footage and CLog 3 footage so they look as close as possible together.

Secondly, similar question, if I recorded in Apple Log and then recorded on another device in Apple Log 2, but then converted both to Rec 709, would they both look the same?

Many thanks

The reason you color grade is to (1) give your work the "look" you want. It is an artistic decision and (2) to match color between shots taken in different light or with a different camera. The reason you shoot "log" is to give yourself more freedom in grading. If you shot H.265, you can't change it much later in post.

How to make the color the same between two cameras? The same way you make the color look the same with one camera but shot under different lighting. As you shoot during the day, the sun moves and the color of the light changes, but you fix that so it matches. You have to do the same if you have different cameras.

You could just blindly apply a LUT. Then you change color space, but the footage will still track changes in lighting and the difference between cameras and lenses. Changing the colorspace moves everything the same distance. So if it were all different, it would remain all different.

 

[macman4789]

Thank you for all your replies, for a beginner like me it has helped me to understand a bit better.

The cameras will be in a consistent indoor space with the same lighting conditions throughout but I just want both cameras to look the same so I figured shooting log would give me the best chance of this?

 

[lin2log]

"I’m trying to know the best way of matching up say iPhone log footage and CLog 3 footage so they look as close as possible together."

The best way to get log footage to look the same is to grade in a common gamut. In Davinci Resolve, that common format can either be Davinci Wide Gamut or ACES. This is done via a color space transform (CST) node. Not certain how to do that in FCP.

"Bottom line: if you're converting/viewing/editing in 709, why even record in LOG to begin with??"

One records in Log to get more dynamic range in the final graded result prior to converting to Rec. 709. Again, in Davinci Resolve this is done with a CST node that converts from Davinci Wide Gamut to Rec 709.

😂😂

ACES? Seriously? CST node? 🤦🏼‍♂️

You don't seriously think that a self proclaimed beginner, who doesn't even know what a LUT is or how to use one can make heads or tails of anything you wrote, do you? Never mind not knowing the first thing about "color grading". Read the room.

So again: zero point in shooting and log in his case. Unless of course you're masochistic and enjoy making your life exponentially more difficult than it needs to be. In which case… All the power to ya!

 

[smithdr]

😂😂

ACES? Seriously? CST node? 🤦🏼‍♂️

You don't seriously think that a self proclaimed beginner, who doesn't even know what a LUT is or how to use one can make heads or tails of anything you wrote, do you? Never mind not knowing the first thing about "color grading". Read the room.

So again: zero point in shooting and log in his case. Unless of course you're masochistic and enjoy making your life exponentially more difficult than it needs to be. In which case… All the power to ya!

The OP asked how they were going to make clips shot in log from different sources look the same. The way to do this is to put each clip in a common color gamut. The only way I know how to do this is in Davinci Resolve using a Color Space Transform. So my comment is appropriate. It is incumbent on the user to learn how this might be done. There are plenty of resource available on the internet with this information.

The OP knows enough that they want to shoot in Log because they believe they will get better results--that is correct. So telling them, as you did, “to just shoot in Rec 709 because they are eventually going to convert to Rec 709" is just dumb and demonstrates a lack of understanding on your part.

 

[ChrisA]

You don't seriously think that a self proclaimed beginner, who doesn't even know what a LUT is or how to use one can make heads or tails of anything you wrote, do you?

The OP wrote: Thank you for all your replies, for a beginner like me it has helped me to understand a bit better.

When I answer questions, I assume if the questioner is serious, he will Google terms he does not know or ask. He asked how to match footage. I basically said "you just got to use your eyeballs and do it." But I hope he will quickly find the display called "Waveform" that helps you to see better.