You may have seen that Sony are releasing a free firmware update in the next week or so for the PMW-F3 that incorporates a new version of S-Log. You will still need to have purchased the S-Log upgrade in order to use S-Log, but now there are two variations of S-Log, normal S-Log and EI S-Log.
EI S-log differs from the original S-Log in that the base ISO is 800 as opposed to the 1600 of the original. You can select either S-Log or EI S-Log mode in the menu. When EI S-Log is selected you have the ability to then add EI gain to the MLUT’s (Monitor Look Up Tables or LUT’s). When you switch the EI ISO to 1200 for example, the additional gain is added to the LUT to give the equivalent S-Log + 3db gain output on the monitor out and to the SxS card recordings as using S-Log with gain. But the actual S-Log output on the A-B dual link outputs remains fixed at 800 ISO. The benefit of this is that what you see on the monitor out represents what you will end up with after post production with added gain or lift, it’s a way of pre-visualising what you will finish up with, without compromising your recordings.
Theoretically, if the cameras native 0db gain point is represented by 800 ISO. Which is what you have when using 50/60i standard gamma at 0db. Reducing the cameras S-Log gain like this by 6db compared to the previous or standard S-log base ISO of 1600. Should yield a 6db (1 stop) dynamic range improvement. Given that S-Log already improves the dynamic range by about 1.5 stops, then on paper at least, EI S-Log should yield a 2.5 stop improvement over the 11 stops the standard and cinegammas give. That would make the F3 a camera capable of 13.5 stops which is quite remarkable. I hope to be able to measure the actual DR very soon and see if this is really the case. Anyway, whatever the outcome of the DR measurements, the EI option is a nice one to have as it will allow you to underexpose a little (to gain extra headroom) when you shoot and then use the added EI LUT gain to check that even after gain gets added in post the images will still be noise free enough for use in your production.
A further feature of the update is the ability to change the R and B gain when shooting in S-Log. This will allow you to tweak your white balance. Currently when shooting s-Log you can only use a preset white balance dialled in in 100k steps, there is no option to white balance the camera using a grey/white card.
I would like to ask you if you can rate the real texture dinamic range, not 13.5 stops, more like 5, 6, or 7 stops from lowlights with texture to acceptable highlights with texture, not grades of black or grades of white, thankyou
I’m not sure I really understand you. An F.Stop is an F.Stop, it is a doubling of the image illumination level, or a 6db increase. If you use any of the standard measurement techniques for video or film cameras with a standard F3 your will come up with a measurable range of 11 stops, 12.5 with S-Log. The only ways you can consistently and accurately measure a range like this is to use accurate solid shades of black through grey to white or uniform light source or sources, increasing in known intensity. For the measurement to be accurate the illumination must be uniform and without texture. My measurements are completely in line with every other test out there, in particular i would draw your attention to the very meticulous tests done during the SCCE testing. What you measure is the darkest point where you can discern an increase in output signal just above the cameras noise floor and the brightest point where you can discern one brightness level from the next just as the camera/DSP goes into saturation and there is no further increase in output, this gives you the contrast range or dynamic range. It is of course obvious to consider that if you can discern one brightness or illumination level from another then you would also be able to discern some degree of texture. The entire range after all is where there is a discernible level change. As soon as there is no longer a discernible level change (and thus the inability to see/measure texture) you are outside of the measured DR.
Including texture, would mean including a measurement of contrast which is a combination of resolution, frequency response and dynamic range (MTF) and with so many variables would not give a repeatable nor consistent result when comparing like for like dynamic range. For example if measuring textured surfaces a camera with a higher MTF would score better than a camera with a lower MTF, but it’s not MTF we are really interested in when looking at DR. MTF can and should be measured separately and considered along with DR when evaluating a camera, but they are two different things and should be evaluated separately.
Hi Alister,
meaning that no +dB will be recorded to the Slog via A/B…
that leaves all the gain changes to post workflow. do you think this will be better than
doing it directly to the sensor/in camera?
Surely if you record to sxs you’d want that to happen in camera…
cheers
stefan