LUTs for LOG: Why You Should Use a LUT with LOG Footage - DaVinci Resolve 14
If you’re new to shooting a LOG profile with your camera and are finding that the color of your footage isn’t looking as natural as you’d expect, it might be that using the camera manufacturer’s LOG LUT will make a big difference.
This was my exact situation: I started shooting with the Blackmagic Design Ursa Mini Pro using the “Film” profile (which is a LOG profile). But I found that skin tones generally looked rather too pink or magenta. I was baffled until my friend Jacob Fenn, who is a colorist, showed me this technique in DaVinci Resolve 14. Simply using the color space transform effect to apply the BMD 4.6k LUT solved the problem!
Links to gear discussed and used to record this session:
Blackmagic Design Ursa Mini Pro Cinema Camera
Ursa Viewfinder - Good for when shooting outdoors in the sun
Ursa Mini Pro SSD Recorder -allows you to record to standard, affordable 2.5” SSD drives
Anton Bauer 90Wh Digital Battery - about 2 hours of life with viewfinder and SSD recorder. This battery keeps track of a bunch of metadata which the Anton Bauer performance charger takes into account to optimize charging
Sigma 24-70mm f/2.8 OS ART Lens (used on the single shot of Cary on my Ursa Mini Pro)
Electrovoice RE20 Dynamic Microphone (This is what I used to record the voice over for this episode)
Antelope Audio Orion Studio Audio Interface (Thunderbolt and USB 3.0)
Copyright 2017 by Curtis Judd
Panasonic GH4 VLOG for Purchase?
For many months, we GH4 shooting enthusiasts have been awaiting Panasonic's new firmware to include a VLOG profile.
For those not familiar, a log profile allows your camera to capture video in a way that can potentially compress shadows and highlights so that they do not digitally clip. They do this by applying a logarithmic curve to the captured images.
As an example, when you shoot a scene where there are some things in shadow and other things in bright sunlight, either the shadows or highlights lose all their detail. The image below is a good example. In this case, this is supposed to be a scene that was shot in VLOG and then graded so that details remain in both the trees above and the shadows of the waterfall below. Normally, one of those would be blown out or crushed.
When the GH4 was originally released, it included a Cinelink D profile which was sort of similar to a logarithmic profile but it was more of a flat profile where it mainly just de-saturated the color values and reduced the contrast of the overall image. That's not quite the same thing. And, it seemed to be doing more than that. I found that Cinelink D worked ok for some landscape type shots but it did rather odd things to skin tones. So I very rarely use it.
A log profile, however, should essentially give you additional dynamic range - the range of luminance values you can capture. However, the GH4 records to 4:2:0 (color subsamping, which is consumer grade) 8-bit color. While this works decently if you're not going to grade heavily, it can begin to fall apart pretty quickly if you try to make any sort of exposure, contrast, or color grading adjustments in post production.
On the bright side, the GH4 can send a 4:2:2 10-bit stream out its HDMI port which I use to record to my Atomos Shogun recorder. I'd like to test whether that makes a difference at all.
However, Panasonic has done something a little different here. Like with most professional grade cameras, they are selling the ability to turn this feature on. You don't just get it for free. That's pretty common in the pro camera world.
In the world of consumer products, paid firmware upgrades are not as common. And for many, this paid approach is a little disconcerting.
Arguments can be made for both sides (why should I have to pay for a software enhancement that my camera hardware is capable of supporting? Why should Panasonic not charge for the research and development they poured into this effort?) I get the reason for the price. It sort of makes sense. I'm not thrilled to plunk down $100 for the feature, but I understand that they need to at least cover the cost of their R&D.
Some may argue that the Sony a7S and a7RII already have log included. But keep in mind that those cameras are priced at over $2000 and $3000 USD respectively whereas the GH4 was originally $1700 and now sells for under $1500 USD.
Nevertheless, it is a little bit awkward since Panasonic is a little later to the LOG game for a camera that has been on the market for about 1.5 years. Also, my impression is that the largest user base of the GH4 are enthusiasts and low to no-budget filmmakers. Not the entire user base, but probably the largest portion of it by quite a lot.
I'd like a way to test it out before committing. But maybe that's what Panasonic is doing here; selecting out a user base that is more likely to actually understand log profiles and how to use them properly.
I think I'll wait to see what people can accomplish with VLOG in practical terms before plunking down the $99.
