S-Log2: Sony's logarithmic gamma curve that preserves sensor dynamic range for post-production color grading.
S-Log2 is a logarithmic recording gamma curve (transfer function) from Sony, not a lighting or grip device. It is activated in-camera as part of a Picture Profile and stores the signal captured by the sensor in a way that preserves the widest possible range of brightness and contrast. The recorded image therefore appears flat and desaturated; the final look is only achieved in grading (post-production). S-Log2 was introduced in 2010 with the Sony PMW-F3 and is matched to the associated wide-gamut color space specification S-Gamut; it therefore usually appears in profiles as the S-Gamut/S-Log2 combination.
S-Log2 is a pure recording curve and does not define physical lamp values. Characteristic are the tonal assignments of exposure and its behavior compared to its successor S-Log3.
| Reference Value | Position in S-Log2 |
|---|---|
| 18% Middle Gray | approx. 32 IRE |
| 90% White | approx. 59 IRE |
| Dynamic Range (Sony Specification) | up to approx. 1300% signal range; Sony states around 14 stops for this, though in practice the usable range is often estimated to be somewhat less |
S-Log2 is chosen to record highlights and high-contrast subjects with ample latitude; the actual image creation is done in color grading. For on-set monitoring, exposure aids (zebra, false color, histogram) and a LUT-capable monitor are used to generate a corrected Rec.709 preview from the flat S-Log2 image.
The successor S-Log3, introduced in 2013 with the v3.0 firmware update for the Sony PMW-F5 and PMW-F55 (along with S-Gamut3/S-Gamut3.Cine, later also for the F65), offers about 1.5 stops more dynamic range, a more purely log characteristic in the shadow and mid-tone areas, and behavior in terms of gradation that is closer to scanned film. The F55 itself was initially launched exclusively with S-Log2 gamma. In contrast, S-Log2 is considered advantageous in very high-contrast scenes with a high proportion of light.
Ich setze S-Log2 ein, wenn ich weiß, dass das Material intensiv gegraded wird und schwierige Lichtverhältnisse vorliegen. Die Base-ISO von 800 zwingt mich zu präziser Belichtung – ich belichte grundsätzlich 1-2 Stops über und ziehe in der Post runter, um Rauschen zu vermeiden. Das Monitoring über LUTs ist essentiell, da das ungegradete Material für Fokus-Pulling und Belichtungskontrolle unbrauchbar ist.
S-Log2 gibt mir in der Postproduktion die Freiheit, die Stimmung eines Bildes drastisch zu verändern, ohne bei der Aufnahme bereits festgelegt zu sein. Besonders bei Szenen mit extremen Kontrasten kann ich später entscheiden, ob die Schatten gehoben oder die Lichter gedämpft werden sollen. Die flache Aufzeichnung erfordert jedoch präzise Kommunikation mit dem Colourist über meine visuelle Intention.
S-Log2 verlängert die Postproduktionszeit erheblich, da jede Einstellung gegraded werden muss – das bedeutet mindestens 20-30% mehr Zeit im Finishing. Die Speicheranforderungen steigen durch 10-Bit-Aufzeichnung, aber die Flexibilität reduziert Drehtage bei schwierigen Lichtsituationen. Für Low-Budget-Produktionen ohne erfahrene Colourists ist Standard-Gamma oft kosteneffizienter.
1. Was beschreibt „S-Log2" am besten?
2. Zu welchem Department gehört „S-Log2"?
3. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?
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