I continue to pick at a question about where Sony places tone values for its in-camera jpg generated images. My question this time is how manufacturer default settings effect luminance.
In the Sony BIONZ and BIONZ X universe I've noted that Creative Style Black and White jpgs at its out of the box manufacturer default setting clips the shadow areas hard compared to sensor RAW. The Creative Style BW range of tone expression is compressed into a narrow range. It's a very steep curve into darkness.
It's this tonal compression that sent me in search of ways of expanding the in-camera generated Black and White jpg tonal range and found using DRO at specific values useful. DRO2 or DRO3 raise the shadow values in a controlled way, though the bottom of the tonal range is still -5EV/Zone 0. By comparison, RAW files using very early NEX reach pure black at -7EV and later sensors from A6000 onward reach pure black at -8EV or -9EV.
That's on the stills Creative Style side of the Sony systems I have.
On the video side in the BIONZ X systems I have there are additional imaging functions under the heading of Picture Profile. I originally thought these were an extension of Creative Style. Only recently did it occur to me to confirm/deny this.
Et voila! here I am with ever more words and illustrations of what I've found.
For this post I share the Sister of the Mother of All Digital Zone System Charts for a Sony A6300 that I have. Illustrating the effects of parameter changes (contrast, knee, etc.) are not covered here. That would be the Mother of All Digital Zone System Charts had I taken the time to do all that. However, I feel a pretty clear understanding of Sony is doing can be developed. Additional details and refinements are left to the reader to pursue.
As I leap off into the deep end of things I should note that the process used in all my Digital Zone System work is easily implemented on all non-Sony systems. All this is simply noting how cameras place luminance values given the various imaging functions a manufacturer offers. In fact, I've spot checked this entire approach against Panasonic Lumix S9 and Fuji GFX100RF systems and found the basis of understanding holds true across at least three manufacturers cameras.
Setup ~
- RAW processed 1EV separation values as reference
- In-camera generated 1EV separation jpgs for...
- Creative Style Black and White with settings at manufacturer default
- Picture Profiles selecting...
- Gamma
- Color Mode Black and White
- All other settings at manufacturer default for each Profile
Results ~
Comments ~
Looking at the result in columns from left to right...
RAW 0EV - This is my tone value reference. Though not shown here, -8EV is pure black. 1EV tone separation is achieved from -8EV to +2EV. From +2EV to +4EV is the "shoulder" of the curve (ala film). Film stopped being 1EV separated at -2EV, which explains why digital imaging systems offer a TON more shadow detail than film when 0EV (the standard) is set at Zone 5.
Creative Style Black and White - Pure black is -4EV Zone 1. Pure white is +4EV. Zones 4 through 1 show a steep drop in tone compared to the RAW reference. Visually, images made using this setting are contrasty with what I would call "inky" blacks.
Sills - The first Picture Profile "style" I come to shows what appears to me to be a very similar result to Creative Style Black and White.
Movie - This Picture Profile is the first illustration I come to of Sony moving tonal values compared with Creative Style Black and White and Picture Profile Stills. Notably, the shadow values are "opening up" with Zone 0 being properly pure black. This setting behaves similarly to what Creative Style with DRO enabled can do. If there was nothing further, at its default setting I feel Picture Profile Movie could be a satisfactory in-camera jpg imager.
Cine 1 - Now we're cooking with gas. Tonal values are expressed through EV -6 Zone -1, though the highlights are a little "hot" with how close +3EV is to pure white. To correct for the highlights being "hot", under-exposing by -0.3EV moves the entire curve appropriately (to more closely match the Zone System definition). For the way I was trained to "see" BW images from all the way back into the Film Days I could stop right here.
A very useful BW Sony recipe:
- Picture Profile Gamma Cine 1
- Color Mode Black and White
- -0.3EV
- All other Picture Profile Cine 1 settings factory defaults
Cine 2 - Wackiness ensues. Highlights are strongly compressed. Perhaps if someone is "color grading" video, having tone value in the highlights could be interesting. For BW stills work? I'm not so sure. YMWV.
Cine 3 - Hah! Another potentially useful manufacture default Picture Profile. This is very similar to Cine 1, except for the exposure as the tones are expressed. There's no need to -0.3EV with this setting. It seems usable straight out of the box:
- Picture Profile Gamma Cine 3
- Color Mode Black and White
- All other Picture Profile Cine 1 settings factory defaults
Cine 4 - This Picture Profile setting sets -5EV as pure black, where Cine 1 and Cine 3 set pure black at -6EV. Said another way, Cine 4 appears to be using less of the native dynamic range of the sensor that Cine 1 and 3. Depending on the environment a person shoots in, this could be sufficient as an out of the box Color Mode BW setting.
SLog 2 - All Holy Hell breaks loose and the FULL dynamic range of the sensor is expressed. +4EV down through -8EV have tone. Images using SLog 2 "look" flat. Referencing back to how my eyes were trained on film prints, SLog 2 "feels un-natural." It's a strange sensation.
Of course SLog 2 is meant for video work and the output of this setting is expected to be color graded after the fact. That's where the Cool Kids get to apply their oh so special color LUTs to achieve certain "cinematic effects."
For BW stills work I envision this setting being useful in extremely high contrast situations, then off-loading a jpg from the camera to a mobile device for processing where an 8bit color space is all that's available. Otherwise we'd just shot RAW and process it in a 16 or 32 bit color space, right?
SLog 3 - Ack! Here we go again with crushed highlights. I see zero value in this setting for BW stills work.
No comments:
Post a Comment