F35 Beginners: Exposure for S-Log

starcentral said:
2.) You can just rate the whole camera lower all together (ie. so you're lifting the tones across the entire range evenly) which in turn means you're shadows are brighter, but so are your mid-tones and highlights. Later in post your bring the whole exposure down evenly across the entire tonal range. You also effectively increase the signal-to-noise ratio of the entire image but at a loss of your range in the top end. ie. highlights.
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This same as ETTR no?
 
Yes. Also called "CineEI" mode on the Sony's. For example you set the EI gain to one stop lower than camera's base ISO rating and you expose based on what you see in the viewfinder as well as waveform levels, but underneath the signal is overexposed by one stop. But you eat away at the highlight latitude. On F35 or Alexa it seems forgiving to do this. Not the case with F3/F55 as I have seen... and probably not with F65 either.
 
I don't want to speak for everyone, but in general you can expose skin where ever you want based on the rest of the scene, perhaps other tonal ranges you're trying to protect, etc..

Generally I place skin 1 stop under middle grey but it depends on skin color too.
 
SJX said:
You guys exposing skin with 38% in slog?
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Only if I want it to be a stop underexposed. Most skin tones are significantly brighter than middle grey, so exposing them at middle grey makes no sense unless you want them to be underexposed.
 
a white card which reflects 90% on a normal scale, is 68% in slog. So if you use zebras you can use that as your guide.
 
JMtheDP said:
So, I've recently bought a lightmeter after a couple of years without (don't ask) and I have been using it with the F35. I've come to some interesting conclusions and thought I would share. Nothing is going to be particularly revelatory to those who have done some exploration of the topic, but I thought it warranted its own topic on here for any other people coming to the F35 family, especially those coming from a non-film background.

Previously, I have been exposing by eye - the technique I have used very successfully for years on my F900 with a mild gamma curve. For the F35, I always shot in S-Log but always never used a LUT to monitor.

I only ever turned the LUT on for dark scenes, thinking that for most daylight work, it just blew everything out and looked crap.

When I got my lightmeter, I started using that to meter. I rated the camera at 400 ASA, because I am a conservative type with exposure. I know this camera has stupendous highlight ability, so I wanted to play to its strengths.

But, I couldn't reconcile what my meter was saying with what the camera was saying. Everything looked underexposed, and very, very flat. Nothing came even close to clipping for a lot of the shots. Previously I would use a waveform along with my eye and try and land the scene dead-centre for exposure. However, when it came to processing the footage, any instant LUT just over-exposed everything.

Why? I was over-exposing. The F35 is truly like film. In nearly every way. I have been shooting a lot of interiors recently and the reason my waveform looked a little low and thin was the scenes were not coming even close to stretching the camera's abilities. Skin-tones go very low down, around 40 IRE, because the camera has a lot of headroom. Noise levels are "acceptable" - it isn't grain free but I don't mind a bit of noise - it is natural to me.

I was most impressed when I was exposing a scene today, in comparatively crappy English weather. I exposed according to the meter, checked my waveform. It looked fairly stingy - everything happening from 20-40 IRE. Then, I panned up to the sky. The waveform peaked around 85 or so - the camera was holding detail in a very bright sky and a very dark brick wall. Very nice. Had I exposed my "traditional" way, this would not have worked.

So, I am learning to un-trust my eyes and re-trust my meter. It is proving very interesting. For further reading, I really suggest seeing a more detailed article, with pics, by Timur Civan, below

http://timurcivan.com/2011/09/sony-f3-slog-testing/

Hope this helps some people, would love to hear opinions on this

James
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This is great write up.
 
So I want to improve my exposure workflow with F35. So far I do by eye because:

JMtheDP said:
But, I couldn't reconcile what my meter was saying with what the camera was saying. Everything looked underexposed, and very, very flat.
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This exact what happen if I try use the meter. I check meter and it say T4 and I put lens on T4 and it don't look right. So I'm doing by eye so far. It works good but I want to start using other tools. Like zebra. But I want to ask how people use zebra with F35 and slog. What you set zebra 1 and zebra 2? Do you use lut or look at slog?
 
You can trust a meter, a meter is consistent. Don't trust your eyes. From my exposure tests with the camera, I needed to rate it at 400 ISO in SLOG in order to have middle grey land at 38% where it's supposed to.

If for some reason you can't simply use a meter, then at least use something like false colour metering to set your exposure, so you know where your exposure actually lies.
 
But meter is like JM said. Meter tells you and camera don't agree. I don't have any gear with false color now. So I want to use zebras. 90% white in Slog is 65%. So set high light zebra to 65%. But what about skin zebra? Around 50%? Skin should be higher than 18% gray. 18% gray in Slog is 38%. But then need to monitor in Slog right? LUT in F35 is rec709 and will change these zebra values. Correct?
 
There's literally no difference between using zebras, false colour, a waveform or a lightmeter to set exposure values. If your targets are 38% for middle grey or 65% for white, then properly exposed you'll get the exact same result with each and every method.

You simply have to run some exposure tests with your lightmeter in advance to determine the ISO at which it yields you middle grey at 38%. Once you have that dialed in on your meter (for me it was 400 ISO for my Sekonic and the F35) you can expose however you want - at key, half a stop over or under, two stops over or under - you can do whatever you choose to do, and the camera will respond accordingly.
 
If you don't believe a light meter can give you the proper exposure level for grey, and want to work with it as your reference point, then don't work with it. Some people just hate using light meters, I on the other hand do like using them but who cares what I think. There are so many other exposure tools and techniques available.

Get yourself a 7Q and you can have a dozen exposure tools at your disposal. :happy:
 
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I found by the way if exposing outdoors, especially under bright sun, it's very important to shield the meter - that'll give you better results. Just see what works for you.
 
JMtheDP said:
I found by the way if exposing outdoors, especially under bright sun, it's very important to shield the meter - that'll give you better results. Just see what works for you.
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Good tip. Problem with my meter too is it's incident only. So is hard to depend only on meter when shooting things faraway like buildings etc. Why I want to use zebras more now.
 
Everybody. I know there are many tools for exposure. But I'm asking about zebra specifically. But it looks like nobody use them or want to share. I have no interest of buying a 7q.
 
I stopped using zebras for S-Log, I would only really want them for the "clip" point. S-Log compresses the dynamic range so much, zebras for skin won't be too helpful as they are with 709 cameras, in my opinion
 
Yes I believe the viewfinder zebras are based on the LUT used, not the log image. I never liked the F35's LUT. Horrible thing.
 
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