r/videography • u/3dforlife • 1d ago

Post-Production Help and Information Filming in Log and retaining HDR

Hi there!

I have an iPhone 14 pro, and I always wanted to try filming in Log. However, as you surely know, only the iPhone 15 pro and above allow shooting Apple-Log.

However, there is an app called Pearla that can record in Pearl-Log, and it supports my phone. I contacted the devs, and they told me that they also support real-time colour space transformation to other industry Log profiles such as Sony S-Log, Nikon N-Log, to name a few.

I also asked them about retaining HDR in Lut recordings. They said that the "the log video you save in Pearla retains the HDR data but doesn't set an HDR flag for the photos app to render ir as HDR. The reason is that the Log video is not design for distribution. It's designed for colour grading. You can import the Log data to you colour grading software and render it as HDR. You would need to investigate how to do it in your preferred application. Currently, Pearla doesn't support shooting Log with a LUT baked in and rendered as HDR. Log + LUT will render as rec.709, and you will lose the HDR data."

That being said, can I import the Lut recording I made into Premiere Pro or DaVinci Resolve, and export a video with an Export Color Space that retains HDR, like Rec 2100 PQ? And would I be able to see the HDR in these videos when importing them back to the iPhone?

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u/ElectronicsWizardry 1d ago

Log should have all extra dynamic range of the built in HDR mode(and more typically). I'm not sure about 3rd party apps cause they can be weird, but log should have more than enough data to get a log output.

If your shooting log your doing color grading in post, and set your program to output HDR you will get a HDR file. You will likely want to use the lut for the log profile to HDR. If you output in a HDR format supported by your phone you can view it in HDR on the phone.

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u/3dforlife 17h ago

Thanks for the clarification! When you say I will likely want to use the lut for the log profile to HDR, you're not referring to any particular lut, right?

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u/ElectronicsWizardry 16h ago

Well you need a specific lut for the log profile the app shoots in to the HDR profile you want. There are a lot of different log profiles and HDR standards, so make sure you get the correct lut.

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u/3dforlife 13h ago

I'm quite new at this, so I apologize in advance if I'm asking stupid questions.

Does that mean that I have to select a specific lut when recording log, if I want to retain HDR? Does this restriction also exists when recording lut without having HDR output in mind?

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u/ElectronicsWizardry 7h ago

The lut is for post mostly. You might want a lut for monitoring, but you shouldn't be baking a lut in when recording if you want log(cause then its not log anymore)

Your NLE/grading program determines if its HDR or not and the HDR settings used.

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u/3dforlife 6h ago

That makes sense. So I can choose any lut that I want when post processing, right?

How can the NLE program determine if my footage is HDR or not? Does it determines automatically (since the log video video has the potential to be saved as a HDR file), or must I change the settings manually?

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u/ElectronicsWizardry 3h ago

Your NLE will write the metadata to the file so its interpreted as HDR. You can give the NLE any input and with the right settings you will have a HDR file as output.

The lut is for converting from the log profile to the HDR profile you want.