FS7: Fair To Say? S-LOG 2 for day and S-LOG 3 for night

This is interesting. I certainly cant see Slog3 having more usable DR than Slog 2.. here is a patch 10stops below clip.. Slog 3 is brighter and more noisy which to me equates to nothing.

Slog_Shadows.jpg
 
As for the OPs question about the best performser in low light. Well I tried to conceive a test..

Slog, illuminated so that the white patch sat at 50 on the WFM.. (this was LED panel on 7%, T4, 1/64 ND) - I decided that having no values above 50 on the WFM counts as a 'thin' exposure.. the sort of exposure one might hope to make in 'the dark'

(actually I decided later that this is not really underexposed enough to cause proper chaos)

So we set SLOG2 so the white patch is at 50. We then leave the light and iris and select Slog3 and Slog3Custom18dbGainNoise_Med.

I then move each file into DR and correct so the white patch now sits at 80, and match blacks best as I can..

Result.. Im giving it to Slog Custom.. just... enough to change settings mid shoot.. probably not :)


Large JPG https://drive.google.com/file/d/0B1BBFhhXu9ReY0V4M2pyNDQxSVk/view?usp=sharing
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noise_EI_CustomSMall.jpg
 
Liam Hall said:
Point is, depending on your shot, in-camera you might expose Slog2 and Slog 3 differently.
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First of all, that is not what you said in your earlier post. And second, that is wrong anyway. Both flavors of S-LOG ought to be exposed pretty much the same, even Sony says there is only a 2 IRE difference between them for white, which is the driving factor for exposure. Point is, it is not a "flawed" test to compare both of them at the same exposure -- even if there might be cases when YOU might want to treat them the differently.
 
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morgan_moore said:
THere is dark and dark.. dark with a (car) headlight is a very wide DR scene.. wider DR than a headlight on in the day time.
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Not sure of your point sir.. depends what the car headlights are doing in the shot.. tiny pin lights miles away..momentarily panning through a shot.. or right next to the camera static full beam.. .. in which case its not a low light shot even if its in the night..

Obviously car head lights on during a bright midday sunlight shot isnt going to make much difference.. or am I missing something..?
 
Donny 123 said:
Not sure of your point sir.. depends what the car headlights are doing in the shot.. tiny pin lights miles away..momentarily panning through a shot.. or right next to the camera static full beam.. .. in which case its not a low light shot even if its in the night..

Obviously car head lights on during a bright midday sunlight shot isnt going to make much difference.. or am I missing something..?
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OP posted about "night" not dark - and indeed that is not really a good metric. Because urban night tends to exhibit extremely wide Dr - headlights - streetlights - signage mixed with dark alleys. While natural night - forest mountains etc present a low dynamic range.

The two situations may be treated with different profiles for best results
 
OK I tried a really grim exposure, basically no lights on in my studio (some ambient creeps in) and 1/16 ND in place on the camera.

I put the white chip at about 40 when in Custom 18dbg mode (to my eye an huge underexposure.. maybe what you would get in a shady back alley at night?

I then moved to Slog 2 and 3

To my eye once you are really trawling the grime to try and rescue your underexposed image Slog Custom is better than EI

https://drive.google.com/file/d/0B1BBFhhXu9ReOFh1dDZkQzVvWjQ/view?usp=sharing

really_dark_small.jpg
 
Doug Jensen said:
First of all, that is not what you said in your earlier post. And second, that is wrong anyway. Both flavors of S-LOG ought to be exposed pretty much the same, even Sony says there is only a 2 IRE difference between them for white, which is the driving factor for exposure. Point is, it is not a "flawed" test to compare both of them at the same exposure -- even if there might be cases when YOU might want to treat them the differently.
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I wasn't having a pop at you Doug, but let me break it down for you:

My first comment, that your test was meaningless in regards to the FS7, is quite straight forward; You shot 16bit RAW on F55 and applied different log curves to the same clip in Davinci. It's wrong to make substantive claims about one imaging system based on tests from another. For a test to have meaning it must be conducted on the camera in question. You may well be 100% correct, btw, but it simply doesn't stand up to scrutiny. My advice, as it always is in these kind of debates, was for the OP to do his own test. And test different log curves on different subjects, skin tone for example. I'm sure you'd agree with that.

My second comment was indeed different, I was moving the chat along rather than debate minutiae... Anyway, as you will note in my comment I said, 'depending on your shot you may expose Slog2 and Slog3 differently'. You are right, white values for Slog2 and 3 are only 2% different, but, and this is the important bit, mid-tone values are very different. Slog2 is 32% and Slog3 is 42%. And there may well be instances where that is the driving factor for setting exposure.

FWIW I've tested both Slog2 and Slog3, shooting in camera with the FS7 and made my own conclusions. I think everyone should do the same.
 
Liam what are you personal conclusions?

Ive never dug deep into SLog2 before (pressure of time) and am finding it interesting in a positive way..

S
 
morgan_moore said:
Liam what are you personal conclusions?

Ive never dug deep into SLog2 before (pressure of time) and am finding it interesting in a positive way..

S
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SLog2 gave a little more highlight roll-off, so better for landscapes where there's lots of cloud, but faces looked better in Slog3. Colours were slightly more cyan in Slog2 and slightly magenta in Slog3 - both easy to mitigate and probably just down to the technical LUT I was using.
 
Liam Hall said:
SLog2 gave a little more highlight roll-off, so better for landscapes where there's lots of cloud, but faces looked better in Slog3. Colours were slightly more cyan in Slog2 and slightly magenta in Slog3 - both easy to mitigate and probably just down to the technical LUT I was using.
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The first part is sound, since it is a fact that slog2 allocates more signal to the highlights, while slog3 allocates more numbers to the midtones (where skintones are located).

The second part - color shift - is more an indication that the LUT is not appropriate really.
 
Donny 123 said:
Yes surely logic would dictate that the sole use of Slog 2 or 3.. is for max DR.. if there is a large DR or at night time.. bugger all DR.. why use slog at all.. with its tiny amounts of data in the bottom end.. so it can handle a large DR.. ?
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My point is simple: if you shoot a situation where the DR is required - fine. For example a nightshoot of a city with brigth highlights. Then use log.

But if you shoot a dark night scene in the streets, no significant highlights, use standard rec709 profiles. You will see a better allocation of the lowlights to more stops what will allow you to grade that in a better way, compared to log.
 
wschmid said:
My point is simple: if you shoot a situation where the DR is required - fine. For example a nightshoot of a city with brigth highlights. Then use log.

But if you shoot a dark night scene in the streets, no significant highlights, use standard rec709 profiles. You will see a better allocation of the lowlights to more stops what will allow you to grade that in a better way, compared to log.
Click to expand...

Agreed. .. I only use night shoot as the OP (I think?) had mentioned it.. even with a few street lights or car head lamps.. I wouldn't shoot slog.. let those tiny highlights blow out anyway..
 
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