Sony a7RIV Engineering Dynamic Range

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JimKasson
JimKasson Forum Pro • Posts: 25,804
Sony a7RIV Engineering Dynamic Range
23

I got my hands on a set of a7RIV dark field files, and was able to measure the engineering dynamic range (EDR) vs ISO setting:

14-bit raw, uncompressed

There's a surprise here: the conversion gain changes at the transition from ISO 250 to ISO 320, which is earlier than in the GFX 100 and the IQ4 150 MP, which use the same 3.76 um pixel pitch in BSI Sony sensors. Otherwise, it's about what most of us who deal with this have been expecting.

Some interesting things:

  • There is no periodic spiking in the spectra of the images that would indicate PDAF-striping "fixes" that cause banding in the GFX 100 and Z7.
  • There is low-pass filtering on all channels above ISO 12800.
  • There is low-pass filtering on the blue channel; probably to interpolate over the PDAF pixels.

Details here:

https://blog.kasson.com/a7riv/sony-a7riv-edr-and-dark-field-spectra/

The blog post is pretty technical; I'll be happy to answer questions.

jim

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