Well, it’s not really part 1, since I did some shutter shock testing earlier. But now I know that the camera’s vibration is no problem, I’ll give it my regular testing regime. [Added later: If you’re interested in the a7 noise floor in single shot mode, look here. If you care that the a7 becomes… [Read More]
Archives for February 2014
Can you see the Sony raw compression artifacts?
In the previous few days’ posts, I’ve established that: The Sony raw compression algorithm generates artifacts that can be made visible by subtracting an uncompressed image chosen to stress the algorithm from one that has been compressed and decompressed and subjecting the result to amplification by a factor of 20 or 30. If the delta… [Read More]
Speculating on Sony’s raw compression
Hans van Driest has posted a possible explanation of why Sony uses the tone compression algorithm that it does. It’s speculation, to be sure, but, if true, might explain a lot. Here is is post, lightly edited for clarity. Sony uses column conversion, meaning they use a lot of ADCs in parallel. This, in combination… [Read More]
Removing the delta modulation component from Sony raw compression
Someone expressed interest is seeing how the Sony tone compression/expansion simulation would work with our test image if the delta modulation component were removed, leaving us with only the 13-to-11-bit tone compression and its 11-to-13-bit counterpart. I’m glad to oblige. Here’s the target image in Adobe RGB: Here’s what it looks like in Adobe RGB… [Read More]
Simulating Sony raw compression with photon noise
I added ideal photon noise to the test of the previous post, assuming that the camera’s ISO dial is set to 100. Here’s the simulated uncompressed raw file demosaiced by bilinear interpolation: And here’s the file companded by the Sony compression algorithm and demosaiced in same way, subtracted in a linear color space with Adobe… [Read More]