Kudos to Sony for responding to market sentiments! (press release below). I sent a query to both a Sony PR agent and a high-level Sony technical person, but as yet I have not gotten an answer to whether there is a lossless-compressed option.
UPDATE: it is indeed an uncompressed format. Indeed, needlessly wasteful, even worse than a simple bit-packing approach would allow, wasting ~9MB per image, even setting aside other possibilities for lossless compressed.
I am puzzled why an uncompressed format would be offered versus a lossless-compressed format. The core issue is file QUALITY, not file FORMAT. Lossless-compressed is identical to uncompressed in quality, but saves a lot of space. And it is not a given that an uncompressed format will solve all issues. My prediction is that the Sony uncompressed format will still show issues as compared to the as yet unbeatable Nikon D810 pixel quality at ISO 64. In particular, Sony raw files look “cooked” to me. I do not think that cooked look is just the lossy compression.
An uncompressed Sony A7R II file will be about 42.2 * (14/8) > 74MB per file, assuming the bits are packed. If the 14 bits are stored in two bytes (16 bits) instead of being packed together, then the file size will be at least a whopping 84MB. Versus ~42MB per file with the current lossy-compressed format = double the size.
The language in the Sony press release is unclear: “selectable compressed or uncompressed 14-Bit RAW” — does that mean selectable lossless-compressed? Or the current lossy-compressed? Are we really going to have to deal with the with the (needless) storage demands of ~74MB uncompressed raw files?
File sizes and lossless compressed
Consider the Nikon D810. Its 14-bit lossless-compressed files are usually around 42MB per file, though files with corner-to-corner detail can be substantially larger (or smaller, with lots of blue sky or similar, particularly high key stuff). Uncompressed, its files ought to be 36 * (14/8) = 63MB. Except that Nikon does not pack the bits, so those 14 bits are stored in two bytes (16 bits), wasting 1/8 of the space (2 bits out of 16) for a file size of 72MB + ~3MB of other stuff for a total file size for its 36-megapixel images of 75MB per image.
In other words, lossless compression saves about 30% to 50% of the storage space on average—more for some images, less for others, depending the amount of detail or random noise in the file (entropy).
See File Size as a Measure of Image Detail for more on just how much space can be saved with lossless compression. Years ago I employed other techniques to reduce image size as well. I have three compression patents in my name on lossless compression (though not ownership rights), and I know a little about these things.
Emphasis added in places.
Sony Announces Addition of Uncompressed 14-Bit RAW Still Image Capture for New α Cameras
by Communications 09/15/2015, in Digital Cameras
Son3y Announces Addition of Uncompressed 14-Bit RAW Still Image Capture for New α Cameras
New α7S II to Feature Selectable Compressed and Uncompressed 14 Bit RAW at Launch; Free Firmware Updates Coming for Additional Models Beginning with α7R II
NEW YORK, Sept. 15, 2015 – Sony Electronics, a worldwide leader in digital imaging and the world’s largest image sensor manufacturer, has today announced user selectable Compressed and Uncompressed 14-Bit RAW image capture will be featured in the new α7S II once it arrives in stores this October.
Additionally, they have announced plans to add user-selectable compressed or uncompressed 14-Bit RAW still image capture via firmware update to additional cameras beginning with the recently introduced α7R II full-frame mirrorless model.
“The voice of our α community remains the most important guiding force of our product development plans,” said Neal Manowitz, Deputy Vice President for Digital Imaging at Sony Electronics. “The addition of Uncompressed 14-Bit RAW processing is a direct result of customer feedback. Widely requested by photo and video enthusiasts, we believe the choice of RAW processing types will further elevate the performance of these extraordinary cameras.”
[DIGLLOYD: uncompressed is/was NOT the request of those who understand the matter, it is lossy vs lossless at issue, e.g., file *quality* not file *format*]
The α7S II and α7R II are compatible with Sony’s growing lineup of α -mount lenses, which now totals 64 different models including 13 native ‘FE’ full frame lenses. In 2016, Sony aims to build the native FE lens lineup to over 20 different models, bringing the overall α -mount assortment to over 70 different lenses.
A variety of exclusive stories and exciting new content shot with the new α7S II and a7R II cameras plus other Sony α products can be found at www.alphauniverse.com, Sony’s new community site built to educate, inspire and showcase all fans and customers of the Sony α brand.