T.Stops Blog

Sony F3 – sLog Testing

Today we will be looking at sony’s sLog Update for the Sony F3.  This camera represents so much imaging power in such a compact package.  The whole rig weighs in at about 17 pounds.  Roughly the same size and weight as my old SGpro REV3 setup, when hooked up to a HVX200.

Tools:
1 Sony F3 w/ sLog update
1 Ki Pro Mini
1 set Cooke iPanchros
1 DaVinci Resolve

We recorded with sLog 3G444, out the standard SDI port with the LUT turned off into the KI pro Mini.

The interiors with the candle and lamp tests, are shot recorded Dual link 444 into a Blackmagic card in uncompressed capture. ( with exception to the shot of Tom sitting at the table with the heavy back light, that was to Ki Pro as well)

KI PRO Mini Courtesy of Next Level Pictures

Using the Small HD DP4 to gauge exposure in sLog.  Luckily the HDMI works when using sLog.

Objective, to discover where sLog should be exposed, How it should be treated in post, and what the difference between 709 standard Gammas and sLog in post, and acqusition.

From previous testing the F3 w/ sLog clips to white @ 6 stops over key. Using this information i metered the brightest highlights in each scene to +6 stops, JUST touching the clip point ( or what i thought was the clip point). The dark end of the scale fell to where it fell.

The goal being to see how far down you can drag up the image, and how conservative i have to be with using fill light to maintain an image in the black section of the scene.

OK, So here’s the skinny. You have to expose just as carefully as you would with any other medium. The sLog w/ Offboard capture gives you incredible room to adjust and manipulate later, however like every camera, the closer you get to perfect in camera, exposure wise, the more Oomph your image will have after delogging. That said, 10bit 422 ( and especially 444 capture) gives you and INSANE amount of room to fudge.

For kicks we recorded the REC709 180% LUT as well and tried to match them to see if matching was possible. The Footage can be massaged into a similar looking image, but the highlight quality, grain structure, and shadow retention goes out the window. If you need a very high dynaic range shot with and F3 and dont have sLog, if you at least have a KI Mini, you can get SOMETHING…. it wont be as pretty, but it’ll be there.

These compositions are boring, very boring, but they are carefully chosen. to reflect situations i’ve run in to the last few years, on various shots that have always bothered me and made me wish i had the “Infinite Dynamic Range” as MacGregor so eloquently put it. Well, for the most part, we have that now, at an indie price point. Yes, the Alexa is better…. by about a stop. (when you hit the 13.5+ zone 1 stop actually becomes a lot) but at 1/3 the price, this is terrifying performance. And the fact that i own it, and its paid it self off in 3 months, and i dont have a 70k mill stone around my neck is simply phenomenal.

The thing when shooting sLog thats tricky; it goes against every instinct you have as a DP. You have to under expose, so far down that you think “Theres NOTHIGN THERE!!!!! WHAT THE #$%^ I’M DOOING!?!?!?!?” but use your exposure tools, use your false color, use your wave form. Skin tones stay at 35IRE, High lights on skin @ 40-45 IRE. Dont worry, its ALLLLL there…. The trick is to use spot meter to see how many stops you are from one point to another in the scene. Get a Grey card, light your set, get your highlights to about +6 stops over key, then set the Grey card @ 35IRE with the waveform. You should be set.

The truth is i dont know why, but for some reason, color information, because of the sLog, is more accurate, pleasing, and is retained all the way up to the clipping point. Even 10bit capture on regular 709 doesnt have the same amount of detail in highlights. Its just not retained in the same way. Pay attention to the highlights in the forearms in the “dramatic” lighting shots.

I highly reccomend downloaing the 2gig low compression version to really see in full resolution whats going on, and how Frigging sharp the F3 really is.

Now that Daylight is covered, lets see what happens when the sun goes away….
Below you will see, sLog raw Tiffs, and graded Tiffs. Feel free to DL and grade. For reference, i shot the skin tones at about 35 IRE to Uncompressed Quicktime – 3G 444 sLog, @ 0dB F16, with a 2k Par with double diffusion, and in the shot is a 40w Compact fluorescent. no Fill.

The skin tone is metered at a T16, with the highlight +1 stop, and the fluorescent bulb itself is +9 stops, and the top of the puppy’s head is +3 stops over key.

I am flabbergasted that i can own a camera that has this much imaging power.

——————————————————————————————————————————–

LOG Out of camera:

RAW Log TIFF File.

 

Delogged

RAW de-LOG TIFF File

———————————————————————————————————————————

0dB RAW LOG

Cooke Panchro @ T2.8

1 foot candle.

RAW Log TIFF 0dB

0dB DE-Logged

DE-Log TIFF

——————————————————————————————————————————–

+6dB

+6 dB RAW Log TIFF

+6 dB DE-LOG TIFF

————————————————————————————————————————————

+12 dB

+12 dB RAW Log TIFF

+12dB DE-Log TIFF

————————————————————————————————————————————-

+18dB

+18 dB RAW Log TIFF

+18 dB DE-Log TIFF

In reality i’d be hard pressed to go above +6dB in LOG. it does get quite grainy, though +18 dB in a dire situation is shoot able, and grades rather well considering the source, and technical extreme its put under.

Lots of people balked at the price tag of $3,680 for a “firmware” update, but the simple truth is, its worth EVERY penny.   The F3 which already has a stellar image, just suddenly jumped up in the ranks.  It Jumped up so high, that i actually am going to use it on a feature film i’m shooting in the coming months.

Check back soon!

I will be releasing the plans for free for my “Anamorphic Looks Device

And i will be reviewing the Small HD DP4.

Follow me on twitter @timurcivan

www.tstopcinema.com

-T

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7 Comments on "Sony F3 – sLog Testing"

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I love boring tests that show me the unbiased, straight dope I need to know. I would like to see graded SLOG compared against graded R709 shots to see where the image ends up. I know you did this for the final setup with Tom, but the day exteriors with clouds would be especially informative.

Perhaps we can do that….

it was already done, a few of the outdoor shots we have the 709 original shown where it was exposed just to protect the highlights, and the graded version to try to match the s log version. the mid and lows were so underexposed in the 709 to protect the highlights, everything had to be gained up to match. lots of noise, and you also can’t color match it as well either because it lacked light in areas where there was in s log, so color didn’t fall in the same places.

Did you record to ProRes 4:2:2: HQ? Does the KiPro Mini record S-Log 10-bit or 4:4:4?

Do you know that the Slog is now free with the F3 if you buy it now. Or you can get it as an upgrade for $899. Does that upset you, like it does me, that Sony charged $3660 for everyone who supported this process early and are now looking like suckers. I got mine in December, 2011, and Sony has no intention of offering any adjustments to the early adapters. Just wanted to let you know, in case you might want to complain.

Man tell me about it……

Hello Tim,

I own a F3 along an O7Q+ external recorder/monitor. I can output only 422 uncompressed as I dont have the CBK RGB01 upgrade (no longer available). My question is this:

I dont have a light meter and wanted to know how to set exposure when shooting Slog. Shall I open aperture to the point where my signal displayed on the waveform goes from 0 to 115 IRE ? Or shall I ignore my black level and focus only on the skin tone fall (38IRE) ? What is the correct approach ?

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