120 FPS Global Shutter!!! and more

[neuroanatomist]

Just noticed the native ISO range of ISO 250 - 25,600.

Global shutter comes at a price – noise. According to DPR, Sony claims the a9 III, "...doesn't compromise on ISO performance or dynamic range." Giving them the benefit of the doubt, I suppose they mean that at base ISO the sensor is no noisier than, for example, the a9 II...at the same ISO value. However, going from ISO 100 to ISO 250 on the a9 II costs a stop of DR, and the DR of the a9 II at ISO 100 is already a stop lower than the R3 at ISO 100. Oh, how the times have changed...

[Kayaker72]

Global shutter comes at a price – noise. According to DPR, Sony claims the a9 III, "...doesn't compromise on ISO performance or dynamic range." Giving them the benefit of the doubt, I suppose they mean that at base ISO the sensor is no noisier than, for example, the a9 II...at the same ISO value. However, going from ISO 100 to ISO 250 on the a9 II costs a stop of DR, and the DR of the a9 II at ISO 100 is already a stop lower than the R3 at ISO 100. Oh, how the times have changed...

Yep. And you have to start asking why is the base ISO 1.3 stops higher than the R3?

I did a quick search, while specifically regarding the A9 III, I didn't find that, but Global Shutters in general, it seems that the "solution" allowing a Global Shutter isn't that the data is all processed instantly (if you think about it, 24 million readings/calculations/adjustments truly instantly does not seem likely). The "solution" is to have on-chip and even in-pixel memory. So the data from 24 MP is instantly moved to memory which is they read sequentially by the processor. If that memory is located adjacent to the pixel well, it is taking up surface area on the sensor, so you actually are using less than the full sensor surface area (apparently this has been the case with several sensors), smaller pixel wells (which might lead to a smaller ISO range?). The other option seems to be having the memory behind the pixel well, so the sensor surface area is unimpeded, but you have more distance between a heat sink at the back of the sensor and the pixel wells. Either way, by having on chip memory, you are adding a step to the process and each step increases noise.

Or so I read/watched.

In a way I am glad Sony did this: 1) push the envelope; but 2) mentally, I am now only really looking for faster read speeds.

[neuroanatomist]

In a way I am glad Sony did this: 1) push the envelope; but 2) mentally, I am now only really looking for faster read speeds.

I'm sure we'll see a global shutter from Canon at some point. Canon is definitely not an envelope-pusher when it comes to sensors. Personally, I have not had any issues with rolling shutter effects on the R3. The readout speed is nearly as fast as a mechanical shutter. If Canon brings a stacked sensor to the 5-series, that would give you what you want (or...buy an R3 ).