FS7: Exposing S-log3 in the snow

Well it's not exactly hard to set-up your zebras at the level you want and then hit that target with consistency. Very easy even for mortals. use of a MLUT for setting exposure is only important if someone has fallen into the very bad practice of exposing by how the picture looks in the viewfinder. Something I would never do . That is why we have zebras, waveforms, histograms, light meters, and other exposure tools so we can be accurate and consistent from shot to shot. I like looking at the pure unadulterated S-LOG image in my viewfinder and I never want to base any exposure decisions on a judgement call or just how it feels to me. It is much too easy for my eyes and/or viewfinder to fool me. But my instruments don't lie!

But whether someone prefers using a MLUT or not is not really the point of my earlier post. I was just pointing out that it is quite possible to set exposure without a MLUT and many people do it on a daily basis.
 
Last edited:
Hi Doug.. yes totally agree sir.. just a bit of light hearted banter.. no disrespect intended.. I have your book and some of your scene files in my beast..

Thanks
 
I don't agree. You should learn how to expose correctly using tools but you need to be creative in how you use your stops after that. You need a vision of how your film/footage is gonna look. Using an MLUT (and lutcalc) is paramount for that, in my humble opinion. 3d luts are the future, embrace it :)
 
stokstad said:
I don't agree. You should learn how to expose correctly using tools but you need to be creative in how you use your stops after that. You need a vision of how your film/footage is gonna look. Using an MLUT (and lutcalc) is paramount for that, in my humble opinion. 3d luts are the future, embrace it :)
Click to expand...

With an MLUT applied, just set Zebras to 88% or whatever target IRE normal whites should hit, and its the same deal.

I have just used this technique on three days worth of shooting, but i finally feel confident that my exposure is consistent between takes and lighting situations. Snow and rapidly darkening light set aside. :grin:
 
That will only work on say REC 709.800 MLUT.. others are not white 90%.. LC709A is a fair bit lower.. thats why if you are using an MLUT.. purely for expose purposes.. the REC709.800 is best..
 
Id just check the WFM (showing Slog) and open up until you see clip and then stop down a bit

Clipping is easy to see as the curve goes flat at the top. even easier to see if you have a 502 with the WFM set to fill the screen

S
 
Donny 123 said:
That will only work on say REC 709.800 MLUT.. others are not white 90%.. LC709A is a fair bit lower.. thats why if you are using an MLUT.. purely for expose purposes.. the REC709.800 is best..
Click to expand...

Then put whites at 71% for example, or whatever the correct IRE is.

I have a post it note filled with different exposure percentages for memory when using scene files / luts that i store with my camera. Very easy, and exposure is consistent.

Morgan: Thats ETTR, no? Takes grading to adjust all the various levels in post then, does it not?
 
Martin.G said:
Morgan: Thats ETTR, no? Takes grading to adjust all the various levels in post then, does it not?
Click to expand...

A bit of equalisation in post is pretty trivial if you shoot intelligently keep exposure constant across whole scenes.

ETTR does not always work as the 10bit does not put much tonal detail in the top couple of stops, Id never ETTR on a face on a dark background, for example, but in the case of snow Id go that way personally.

S
 
Thank you for clarification. Indeed, using one of the lines in the WFM as a guideline for snow exposure could work.

We still have plenty of snow, but i have not had time to test anything further yet. Perhaps in the coming days i will have some tests done. Western Norway has all kinds of weather within the same hour, so a consistent way to quickly adapt exposure is critical.
 
Im not talking about any marker line on the WFM, as you open up stop while examining your scene on the wfm you will see the 'hump' in the WFM gets a flat line at the top as you clip.. that is the 'line' I would use.

S
 
Wouldnt that remove all your highlight headroom?

I am shooting in S-log3, so whites should be around 60%, not 95% ?
 
Donny 123 said:
That will only work on say REC 709.800 MLUT.. others are not white 90%.. LC709A is a fair bit lower.. thats why if you are using an MLUT.. purely for expose purposes.. the REC709.800 is best..
Click to expand...

Agreed, I find REC709 800 just looks right in the VF and easy to expose by eye without zebras.

If people are burning their own LUTs LUTCalc shows you the 90% value for your zebras e.g. LC709A is 71, Varicam gamma is 77 etc. Also super useful if you're creating custom gamma curves with different knees and slopes it gives you the right 90% value for you zebras.
 
Martin.G said:
Wouldnt that remove all your highlight headroom?

I am shooting in S-log3, so whites should be around 60%, not 95% ?
Click to expand...

you only need headroom if.. well why do you need headroom?

--

It is important to know the difference between white (card) and.. white (clip)!

When Alichap and others talk white they mean a white card, not a clip point.

so you have a person with a white card and a sunlit snowy mountain behind once you have stopped down so the mountain is (just) not clipped then quite likely the white card in the hand of the model would be at 60-70

If the person is in full sun with a shady mountain behind you would indeed want the card in his hand probably at around 70, not 90 as you lose some tone at the top of the range of Slog.

S
 
Last edited:
Martin.G said:
Wouldnt that remove all your highlight headroom?

I am shooting in S-log3, so whites should be around 60%, not 95% ?
Click to expand...

Only if you need it. There are very few scenes that need all the available headroom which is why you can comfortably over expose by 1-2 stops to get the cleanest image.
 
I think it is important to be able to 'smell' a scene and expose accordingly.

For example a fancy hotel bar with a sea view one would want to expose so that the ext view is not clipped at all.

But a prison scene with a small window having that blown to white could work well.

So there is no rule for exposing 'room with window' .. or any other scene

S
 
Martin.G said:
Then put whites at 71% for example, or whatever the correct IRE is.

I have a post it note filled with different exposure percentages for memory when using scene files / luts that i store with my camera. Very easy, and exposure is consistent.

Yes but if you are not burning in your LUT,and using only MLUT for your VF.. if that is the way want to judge your exposure ..( I do it that way but many people dont.. its just a method you could try..).. they you might as well use the one with max contrast,helps focus too.. and the easiest to judge from .. why bother with a LC(low contrast) 709A MLUT.. if its only in your VF.. do that in post with your Slog footage..
Click to expand...
 
morgan_moore said:
you only need headroom if.. well why do you need headroom?

S
Click to expand...

Because the mountain in the back is overcast when you start the shoot. 3 hours later, its sunny while still shady in front of the camera.

Sure, you can adjust exposure again. But this creates more work in post. My main job is being a producer, so costs and time spent is of big concern to me.

While exposing for 60% white in slog3, i can just note this within the backup folder, and in 5 years time i can pick up where i left and even though i have forgotten every single detail, i can throw a LUT on the timeline and start working immediately.

Exposing white at a certain level creates lasting concistency. I like that.

And judging from the post in the 12bit raw thread right now, the XAVC 10 bit 4:2:2 bit distribution shows theres not really any quality gain by ETTR`ing the footage. Just a lot of post pain and work introduced.
 
I think if you think the camera (or delivery medium) have enough DR to sustain the sun going in and out on a snow scene without changing exposure you are deluding yourself.

If you make consistently hot exposures.. you can just add a single LUT.. just not the normal LUT (the normal luts dont work with cineEI either if your EI value is not 2000)

You could consider boarding that LUT and archiving it with the footage so in five years you have no problems.

If you post person cannot use the exposure slider in the NLE very fast.. well consider a different post person.

--

I think until you actually see Slog 'hot' (not ettr just a bit to the right) as non compressed jpgs you cannot judge if it is worth it. here are some jpg 12 for you to look at, sorry about the face.. https://dl.dropboxusercontent.com/u/33167160/Mugshot-jpg12.jpg
 
Martin.G said:
It still costs time and money to adjust every single shot. If it can be avoided, great! Thats why documentaries go for REC709.
Click to expand...

If you set your gain settings to 500, 1000 and 2000 you have 2 stops and 1 stop of ETTR and it's no more work to load a 500 iso LUT to a 2000 iso LUT. Unless you're incompetent and changing exposure wildly during a scene you should be able to copy a grade from one clip to another with out making any major corrections.
 
You must log in or register to reply here.
Back
Top