Acording to this article https://fstoppers.com/gear/sony-announces-a7r-iii-solid-improvements-built-around-previous-generations-424-201012 the Sony A7r iii uses the exact same sensor as it’s predecessor. Given that how can the A7r iii get .8 stops more dynamic range than A7r ii as tested by dxomark?

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    \$\begingroup\$ Only DxO knows. \$\endgroup\$
    – Michael C
    Jan 20, 2018 at 16:37

2 Answers 2


From the article linked:

advances in circuitry design and image processing mean that the new camera can output all 15 stops of dynamic range in the lower ISOs rather than the a7R II’s 14 stops of output.

Dynamic-range is a ratio, so by improving the circuitry, they can reduce read noise. By having lower read noise, even with the same well-capacity, dynamic-range is greater.

Keep in mind that the sensor may be the same in most of its specifications, it may also be different in some ways or it could be manufactured with an improved process which reduces the amount of stray electrons.

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    \$\begingroup\$ I might be mistaken but isn’t the idea behind a cmos sensor as opposed to a ccd sensor that each pixel does its own analog to digital conversion? If so how can changes outside the sensor reduce this? Otherwise nice answer, upvoted. \$\endgroup\$
    – lijat
    Jan 21, 2018 at 6:06
  • \$\begingroup\$ It is more complicated than that. The A/D conversion happens when you read the photosite but there are different ways to do it, where the gain is done (to get different ISOs), etc. I am not a chip designer but I do know one and I know that there are so much work and details that goes into those things to make them as performant as they are now. \$\endgroup\$
    – Itai
    Jan 21, 2018 at 16:18

Can we start by saying it is not EXACTLY the same? Same generation - yes, but they did make changes. For example they improoved and thanged the autofocus part on the sensor.

It is likely they did some other minor optimizations based on the same sensor design.

Please realize that 0.8 stops is not a lot - they have more than 15 in the old A7RII.

Heck, they even say so in the article you linked. Did you not bother to read it at all?


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