I have done some further research on the picture profiles and found out quite a bit of information.
In this post I will focus on the luminance and black gamma.
Luminance determines the range of black and white that are in the footage. People familiar with the Panasonic GH4 will know that you can set luminance fundamentally in two ranges: 0-255 and 16-235.
What this means that you have in the first case 256 grades of grey and the in the second 220. Some people confuse luminance with dynamic range but they are not the same thing.
You will somewhere find the definition of limited for 16-235 and full for 0-255 this is what it means.
In particular video broadcasting legal luminance is 16-235 so if you use a clip produced at 0-255 the extremes will be clipped this is anyway resolved as the levels are mediated when clips are produced for compatibility.
On the other hand if you use a clip with range 16-235 on a computer that has 0-255 luminance range it will look as lacking deep blacks or whites.
Ultimately you need to decide what is that you are shooting for and if your clips are going to be played on a computer that works in RGB or on a Tv that has YUV.
< 7 stops
< 7 stops
So the only profile that is broadcast compatible before editing is PP6 or the Cine2 gamma curve.
You can see that the dynamic range is the same for PP5 and PP6 so the fact that the camera records more grey levels does not really change things as the cine2 curve is smoother so it can accept higher input signals.
In order to increase depth of blacks it is possible to use the black gamma setting. This has 2 controls, one is the Range Narrow, Medium, Wide and the other is the level that goes from -7 to +7
If you are going to grade your footage of and if you are going to use the video gammas PP1-PP4 you should not touch the black gammas otherwise you risk crushing the blacks.
However if you intend to use the cine profiles straight out of the camera you can tweak the black gammas accordingly.
The range determines where the setting will be effective.
Broadly speaking Narrow works on the first 10% of the signal, medium around 20% and wide around 30-35%.
What it means is that Narrow really works on the deeper blacks as you move to Wide you are altering also the grey and effectively changing the balance of the whole image.
For what concerns the level a positive value will move black towards grey and a negative value shift grey towards black.
There are two main uses of the black gamma: get deeper blacks without altering the overall contrast this is obtained using the Narrow setting and a value between -3 and -7 or use the Wide setting with negative values to give the whole image a darker tone.
A setting of Wide with level around -3 gives an overall darker tone to a Cinegamma if you don’t want to change the blacks in post and remains overall balanced.
Which leads to my current favorite profile that is a customised PP6 setting the parameters that I have changed are:
I have tested the various Gamma with backlight situation and I found that Cinema2 performs best on my Tv where I watch my clips.
I prefer Cine2 even on the computer to be frank but it is true that the blacks are a bit light.
Color mode: I have tried Cinema and Pro am now on Pro with Saturation +8
Black Gamma: Range Wide Level -7 as the cine2 mode is quite dull I like to push the blacks a little overall.
As the Sony RX100 Mark IV records at 8 bit my opinion is that using S-gamut is not worth without an external recorder. And to be honest the amount of grading possible is quite limited so my approach is to get the video as good as possible out of the camera.
The new cameras in the RX100 and A7 series can record 4K video internally but what is more important come with significant enhancements for video shooters.
Probably the most important feature is the availability of picture profiles that have a number of presets that can be further customized by the user.
There are many forums on the internet with custom setting to try to extract cine like look from Panasonic GH4 clips but all in all we can say that the controls in a still camera have been quite limited so far.
The new software that comes with the RX100 and A7 is a real step forward in this respect and contains all characteristics and functionality previously only present on Sony professional and semi professional video cameras.
The Seven Presets
The starting point of using a picture profile is to find one that we like as a starting point for further customization; the new Sony cameras have 7 profiles already loaded with example settings. The profiles have many characteristics that can be configured but probably the most important is the shape of the gamma curve because it also determines the minimum ISO and the availability of other features.
The descriptions above are my personal short description as the user guide is quite confusing.
Profiles PP1 to PP5 are usable straight from the camera, PP6 is optimized for editing and PP7 can’t be used without editing.
The profile PP1 and PP2 emulate the camera behavior in movie and still mode in terms of contrast and saturation. The main difference between the two is that the Still mode has stronger contrast and saturation than movie. Both use a minimum ISO of 125 and they allow customization of the standard camera modes.
Within a profile you have access to controls for color and sharpness at much granular detail that you have with the camera in normal mode. For example the saturation slider goes from -32 to +32 and the sharpness can be completely controlled manually. Colour depth is available in the range -7 to +7 for the whole RGCCYM palette. The customization of those controls lets you have the colours you want off the camera this can be particularly important to people looking for a specific look of certain colors typically red and blue.
Another feature that is incremental to the normal movie mode is the knee setting. The knee is particularly useful with highlights and with back lit shots. What it does it to compress the highlights within the usable signal range.
The knee is a way for those who like video look footage to capture more highlights and avoid hard clipping of back lit images.
The profiles PP3 and PP4 use the ITU709 gamma curve that is the standard for high definition video television. The gamma curve has a low light gain of 4.5 dB and for this reason the minimum ISO is 200.
The video profiles bring substantial increase in both shadows and highlights to the image compared to the standard profiles.
The difference between those two profiles is the selection of the color mode. The PP3 profile has a Pro colour mode that the manual says ‘it is similar to professional Sony broadcast cameras’ the PP4 instead has an ITU709 Matrix colour mode.
What it means is that the Pro colour is slightly below the standard saturation whilst the ITU709 Matrix is extremely saturated looking like the Tv program that go these days. Both settings allow usage of the knee setting in auto and manual mode. The idea is to restore the highlights and make the footage look less harsh. The issue is of course that this has only effect on the highlights and not on the shadows.
The profiles PP5 and PP6 use the two different Cine gamma curves one is limited at 109% and the other at 100%.
Those are the official descriptions:
Cine1: Softens the contrast in darker image areas and emphasizes gradation changes in lighter image areas, producing a subdued tone overall (equivalent to HG4609G33). Gamma curve that obtains a dynamic range of 460% when the exposure is adjusted to 33% video output with 18% reflectance gray. The maximum value of video output is 109%.
Images shot with this gamma can be used without grading, but since the images have smooth gradation characteristics, this can be used to grade and finalize the viewed image in the post-production process.
Cine 2: Similar results to [Cine1] but optimized for editing with up to 100% video signal (equivalent to HG4600G30). Gamma curve that obtains a dynamic range of 460% when the exposure is adjusted to 30% video output with 18% reflectance gray. The maximum value of video output is 100%.
Both curves are cine like and therefore do not use the knee function by default this is because a cine gamma curve is already clipping at much higher signal levels. The Cine2 curve has less contrast than Cine1 and is limited to 100% as opposed to the standard 109% so it is optimized for editing and the footage will lack whites and look fairly grey.
Practically the cine profile achieve a higher dynamic range using a smoother curve, this compares to the video profiles where the curve is pretty much the same until the highlights get compressed using the knee function.
The PP7 profile is for S-log2, this has the highest dynamic range but the minimum ISO is 1600, the footage looks really bland out of the camera but this can be really enhanced through editing to bring out all the details.
My Take on the Picture Profiles
I think the whole cinema like video is a very overrated subject for underwater use. An acid test to understand where you stand is your own TV. If you use the picture settings Vivid or Standard then you are a video like person, waste no time pursuing cinema like look as in the editing you will effectively bring it back and eliminate all the detail you capture by increasing contrast and saturation.
If instead your TV is set to Cinema or is even calibrated then you are a Cine like person.
Personally I think S-log2 for underwater use at 100 mbps is a total waste of time and it is only worth with external recorders. The bitrate is too low to capture that amount of detail and resist extensive grading and actually shooting at 1600 is pretty difficult and requires ND filters (that the RX100 has) to perform decently.
You can take still shots with the picture profile so the first thing to do is to take a few pictures and see what image you like the most, then you can start tweaking.
I found myself to like the cine settings in terms of contrast but I find then too bland in color so I have settled for +20 saturation right now.
Between Cine1 and Cine2 is quite difficult to choose because although Cine2 is in theory optimized for editing actually it looks pretty good straight from the camera for my liking. I particularly like the fact that the highlights almost never clip with this setting even in harsh conditions. It is possible to mix the Cine profiles with the Pro color mode but I found that using saturation was giving the same result.
Detail setting (aka Sharpness)
The last feature of the RX100 and A7 new controls is the fine tuning of the sharpness setting. I find that the default works pretty well except at high ISO where you want to start adjusting slightly the behavior.
But it takes a bit of time to understand the settings.
The starting point for me is the crispening setting that in perfect Sony tradition means exactly the opposite of what you would think. So a setting of +7 means actually limit the sharpening on speckles and noise where a clear shape can’t be detected. Once you set crispening to the max and you shoot at high ISO you see how it reduces the noise. However the issue is that now the sharpness has also reduced so in order to restore the effect you go back to the total level of detail and set it to 7. Once you do that you find out that now the sharpening applied correctly is actually excessive so the limit setting effectively clips the amount of sharpening applied to the edges I use this at 3, as this results in a reduction of highlights sharpening (glass reflecting objects look dull) I then set the highlight detail to +2. After I did all of that the end result was very similar to the standard setting and a bit softer on the edges, practically it was only better at very high ISO so I went back to the original setting.