FS7: LUTS for the beginner

Chris Johnston

Chris Johnston

Veteran
Just trying to get my head around using luts for a more artistic look and not sure on the proper (?) use.

I typically shoot episodic TV for broadcast locally so my fs100s work great with the picture profile I've using. (good clean rec709 look I'm happy with) quick turnaround to the station after minor color/brightness corrections usually.

I'm replacing the fs100s with FS7's and have decided to try to squeeze in some "artistic" narrative type work / fun projects as time allows. (as well as using the FS7s for the TV work.) For the TV work I've been shooting Cine EI slog3 and then applying the lut in post to bring it into a nice broadcastable rec709 ish look. Very happy with the image I've been getting. This brings me to my main question (or misunderstanding) of using luts for a "Look" rather than a correction of "LOG" footy.

I've been using luts ONLY for log "correction" to bring it into a rec709 type image and then doing the minor color/brightness/contrast corrections to my liking. I've only downloaded or purchased a few different lut packages because what I have has worked great. My confusion comes with proper workflow that others may use to get some of the more "artsy" looks on stuff that is for their fun (not TV biz) shoots. I downloaded a free lut package from Lutify.me and 1 or 2 of the luts have a really cool look when applied to the standard "LOG" footy from my fs7. (not something for tv but maybe a music vid or short film)

Reading on their site, it talks about the different "types" of luts. (not talking about 1D or 3D) but more about LOG correction luts, film emulation luts, artistic/creative luts, Sooo...

Are all luts that are out there designed to take you from "loggy" footy to the "end product" (so to speak) or are there luts that are specifically designed to get you from a rec709 ish look to the more artsy look. I've been just applying luts to my log footy to see what it looks like and whether I like it or not, but now I may be rethinking I'm possibly doing it wrong. What do you do? Do you normally get it to rec709 ish and then do the artsy luts or just go from log to artsy.
(I realize luts might be considered a somewhat "lazy" way of getting the end product look you want but if it saves me a bunch of time...then call me lazy.)

PS: If most luts are designed to take you from "loggy" footy to end product (or close to it) aren't log looks for different cameras different? Nikon log looks a lot different than arri log vs sony log vs canon, etc etc etc. If you apply the same lut to different can footage aren't you going to get completely different looks after application?

Sorry for the noob questions
 
Chris Johnston said:
Just trying to get my head around using luts for a more artistic look and not sure on the proper (?) use.

I typically shoot episodic TV for broadcast locally so my fs100s work great with the picture profile I've using. (good clean rec709 look I'm happy with) quick turnaround to the station after minor color/brightness corrections usually.

I'm replacing the fs100s with FS7's and have decided to try to squeeze in some "artistic" narrative type work / fun projects as time allows. (as well as using the FS7s for the TV work.) For the TV work I've been shooting Cine EI slog3 and then applying the lut in post to bring it into a nice broadcastable rec709 ish look. Very happy with the image I've been getting. This brings me to my main question (or misunderstanding) of using luts for a "Look" rather than a correction of "LOG" footy.

I've been using luts ONLY for log "correction" to bring it into a rec709 type image and then doing the minor color/brightness/contrast corrections to my liking. I've only downloaded or purchased a few different lut packages because what I have has worked great. My confusion comes with proper workflow that others may use to get some of the more "artsy" looks on stuff that is for their fun (not TV biz) shoots. I downloaded a free lut package from Lutify.me and 1 or 2 of the luts have a really cool look when applied to the standard "LOG" footy from my fs7. (not something for tv but maybe a music vid or short film)

Reading on their site, it talks about the different "types" of luts. (not talking about 1D or 3D) but more about LOG correction luts, film emulation luts, artistic/creative luts, Sooo...

Are all luts that are out there designed to take you from "loggy" footy to the "end product" (so to speak) or are there luts that are specifically designed to get you from a rec709 ish look to the more artsy look. I've been just applying luts to my log footy to see what it looks like and whether I like it or not, but now I may be rethinking I'm possibly doing it wrong. What do you do? Do you normally get it to rec709 ish and then do the artsy luts or just go from log to artsy.
(I realize luts might be considered a somewhat "lazy" way of getting the end product look you want but if it saves me a bunch of time...then call me lazy.)

PS: If most luts are designed to take you from "loggy" footy to end product (or close to it) aren't log looks for different cameras different? Nikon log looks a lot different than arri log vs sony log vs canon, etc etc etc. If you apply the same lut to different can footage aren't you going to get completely different looks after application?

Sorry for the noob questions
Click to expand...

There is also another path.. which is to record the LUT directly to your footage.. in Cine EI mode.. rather than shoot custom with matrix adjustments.. I do this alot for non LOG shoots. using User 3D LUTs..but you can of course use the in camera ones too.. it can still be tweaked but you have set your look by LUT rather than custom settings..
 
A lut is just a set of calculations that take your footage from A->B. End of.

A super simple lut might go..
IF colour value=234-234-234 THEN new colour value = 264-264-264
This Lut could be titled 'Add thirty to 234'
And would give an input pixel whos value was 234-234-234 an output value of 264-264-264
Obviously this would be entirely useless.
A full lut will calculate a new value for every colour (000-000-000) through to (1064-1064-1064)
The calculation does not need to be simple addition/subtraction but could work on all sorts of complex formulas)


So they can

-Delog
-Add and 'arty look' to 709 footage
-Delog and add an 'arty' look in one hit
-Maybe perform a specific task like matching an A7s to an FS7 (although I doubt this actually works!)
-do some thing entirely random like turn your footage into a 'negative'

IMO the best way to delog footage (especially sony) is to use the delogging LUTs issued by the manufacturer

One can then add 'art' to that if one desires with a second 709->art LUT

Something to be aware of.. LUTs can be 'destructive' so any clipping caused by a lut may not be recoverable with another move in the post chain.

Also a lut with a steep curve may end up calulating values that cannot be reproduced on screen or may clump together values.. aka create banding in skies and other smoot tonal zones of the image.

S
 
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Thanks Morgan, That's pretty much what I figured. Just couldn't figure out how X lut would work with different camera Log files because they are so much different from each other. Guess it's just hit or miss. If you like it use it.
 
morgan_moore said:
A lut is just a set of calculations that take your footage from A->B. End of.
[...]
So they can
-Delog
[...]
S
Click to expand...

+1, Sam. Also - when delogging Slog footage in Resolve, I find the color space transform much more precise by using Resolve Color Management rather than LUTs, which - after experimenting in Resolve for the last 4 months or so - I almost completely abandoned. The color space transform with RCM, applied to Slog source material, gives me much cleaner, more natural looking Timeline which is- above all - much easier to work with in the Color page of Resolve...

Piotr
 
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