FS5: Judging exposure?

What about in Slog2? Normally on the a7s I will just spot meter a grey card and get it to between 1-2 stops over, I can't figure how to do that with this camera. As for cinegammas - zebras set to what? Isn't it ideal to underexpose by a stop or so for that setting?
 
On the FS5, aside from using an external monitor with exposure compensation LUTs, there's no built in tool for handling overexposure so you have to overexpose it yourself. No big deal here's how you do it.

Put a 1 stop ND filter on your lens and setup your exposure to normal and proper levels. Now take the ND filter off, don't change your exposure, and press record. You are now recording 1 stop over exposed. Sure it's pain in ass, but it works.

This tip and more exposure information for working with the F series Sony camera's are available in my 10,000 word 37 page downloadable guides. I should not post links as it's against DVX rules but you can google it :happy:

sony-fs5-small.jpg
 
Doug Jensen said:
75% on bright reflected whites. Simple as that.
Click to expand...

Ok cool but I have to ask because this is something that confuses me using zebras. Set to 75%, introduce white piece of paper - do I want zebras ON the paper or expose just until the paper is free of zebra lines?
 
ScreenShot2014-08-21at55735PM_zps0aed166b.png


If a white piece of paper (or white card) is around 60% in slog, you would be over exposing your image by quite a bit if you set zebras to 75% on a white surface.

Knowing that white paper is actually 60%, what you do is set your zebras to 70-75% and only let it stripe over something that is very reflective in your scene, or highlights for example.
 
voyagervideo said:
Ok cool but I have to ask because this is something that confuses me using zebras. Set to 75%, introduce white piece of paper - do I want zebras ON the paper or expose just until the paper is free of zebra lines?
Click to expand...

You want to see a fair amount of zebra on reflected whites, but not fully covered.

I said 75% instead of 60% so that you will over-expose beyond Sony's recommendations -- that everyone knows are too low.
Also, because of the way zebras work on the FS5, setting the level to 75% means that zebras will actually appear at 70%, so you're really exposing at 70 and not 75 when zebras are at 75..
I've got a 6-hour training video at Vimeo that it explains this (and other things) in greater detail, but like Dennis, I can't post a link. Look and you will find.
 
Currently I use Gamma Assist with Slog2 and set zebras at 70%. I then dial back until zebras are not on white faces (I say white faces coz thats currently what I'm filming) I have been doing this since reading Alisters article:

When shooting in S-Log you can add a gamma assist LUT to the viewfinder to make exposure assessment easier. At the moment there is only one LUT which is the 709(800) LUT. This corrects the gamma in the viewfinder to a much more normal looking image to make getting your exposure right much simpler. I noticed that the cameras Histogram always measures the recorded signal. I think this LUT is going to be the key way of getting good log exposure with this camera, but it’s also very simple to use and that’s what you need for run and gun. Add the LUT and if it looks right, it is right, it really is that simple.

Now I don't know if what he is saying is correct : "Add the Gamma Assist and if it looks right, it is right" but I'm getting pretty good results. I use the Offset in Resolve to bring it back down if its +2 over exposed, and I can recover ample information if windows etc are overexposed. Its quite difficult to expose in Slog2 Run n Gun like what I'm doing but so far I feel its working ok.
 
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What Alister is saying is in reality that with any LUT enabled (like you can enable a "real" 3D LUT on FS7/F5/F55 or "fake" 709(800) LUT on FS5 - I say fake because it will not fix the color or anything only the contrast of the image) you can pretty well expose the image exactly as you see it. ie. if it looks normal in your view finder with the LUT turned on, then underneath it is "most likely" correctly exposed.

Think about it, if you are clipped with a LUT turned on, then you are surely clipping the underlying slog signal that is being recorded. With a LUT enabled if you set your zebras to 70% and only see stripes on highlights or shiny surfaces this is way over exposed because 90% is a white piece of paper, or white table cloth. With a LUT turned on "highlights" or very reflective surfaces should be 98-100% let's just say for argument's sake.

Kapish?
 
Thanks Dennis I think Kapish.

So with the "fake" 709(800) LUT your basically saying use zebras same as using say a Cinegamma? So i am doing it correctly - making sure i dial back faces to not hit 70%? And when the new firmware comes out and we can lower our zebras would u say setting zebras at 50-60% would be a good guide for faces with the 709(800) gamma assist LUT?

(BTW i use Pro colour and not Sgamut cause i like the results and have less colour fiddling in post.)
 
Yeah fake LUT (gamma assist) or real LUT, or 1D LUT or 3D LUT, well any LUT transposes original values from S-Log to some new ones. Most LUTs will have close to REC709 values, but be cautioned they can vary so pay close attention to middle grey, and 90% white (white piece of paper, or white pair of underpants). As you had suggested some LUTs will have similar values to the Cinegammas.

This chart is meant for transposed values for 3D LUTs running on FS7, F5, F55 because they can actually have an assortment of flavoured LUTs. But please note the 709(800) LUT listed there for your very fine conveniences:

Screen%20Shot%202015-10-04%20at%209.00.23%20PM_zpsngajezby.png
 
I think for LOG you already have your answer, Zebras set to 75% on bright white but wanted to add I have been playing with the gamma assist as well.... yes, it makes things look overexposed but but judging from eye just doesn't work for me because going from sun to shade to indoors would effect my exposure (eyes open up and stop down constantly) and let be honest that Sony LCD/EVF isn't anywhere close to reality. Gamma assist doesn't effect the histogram so how the image looks makes no difference but were it is really helpful for is focus... its just so much easier focusing on a contrasty image vs flat. Also I read (Chapman's site I think) that in the next firmware update Sony will give us the ability to set zebras from 0-109 so we can set with zebras from middle grey.... not a massive deal but I find grey cards are easier to work with in bright sun. Get Jensen's video, even the most basic parts of the vids will have little things that are pretty helpful.
 
Thanks Dennis.

Its a pain the ass exposing Slog2 on the run but i do like the finished look.

As there isn't always white reflective paper etc around, especially in ob doc i suppose what i am doing with 70% zebras is correct. I don't want to really under expose because then i would need to lift gamma in post a lot more and then i'd be introducing noise etc especially with the XAVC Long GOP FS5 codec.

So to conclude: Expose the "fake" 709(800) like i would with a cinegamma?
 
Well that is a trick question my dear friend.

Time to do some homework:

Look at the scope charts (provided by AbelCine) for the various Cine gammas. One one of them is close to the values in the chart I provided for 709(800) LUT.

:happy: :beer:

http://www.starcentral.ca/forums/Sony PMW.pdf

(download and save this PDF to your phone, for Sony F3 or FS5 it can be very handy for future reference)

[ EDIT: Ignore the first chart, it is for S-Log1 from the older Sony cams… ]
 
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I did purchase your Ultimate Exposure Guide for the FS5. Nice work Dennis.

where is Sony's literature for exposing using their 709(800) :Drogar-KnockedOut(D

I feel my results at exposing with the gamma assist 709(800) LUT using skin tones just below 70% is working. Although i know Doug Jenson disagrees using Skin tones because of the many different colours of skin. But if i never let them hit 70 and make sure they are quite below the image comes out nice.

Dennis do u have a recommended exposure guide for the FS5 Gamma Assist? Oh i see u already posted a Out mapping pic, didnt see before.
 
Sony's literature is my exposure guide and Doug's video I guess? :thumbsup:

Thank for your support, now I can feed my dog.

In the exposure guide gamma assist is mentioned a few times, and the same mapping table can be found.
 
Well I really hope your dog appreciates me helping finance his food!

I was going to post you a picture of my sons face which i used in Slog2 using my below 70% zebra method but your Contact email on yr site doesn't have a way to add pics. But I'm sure you will live comfortably without seeing it anyways :cheesy:
 
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