Sony A7RV: low light performance with 26 Million Pixels

[LCM94120]

Hello

One of the features of the Sony A7RV is to be able to record 61, 26 or 15 Mpx RAW files.

Using 26 mpx improves low light performance or not? Such as the 24 mpx full frame sensors?

Thanks

Edited April 17, 2023 by LCM94120

[Architeuthis]

Yes, it does. When you downscale the image later to 24 Mp, you get the same amount of noise reduction. No need to do it in advance, unless you want to save storage space...

Wolfgang

[Pieter]

On 4/17/2023 at 3:18 PM, LCM94120 said:

Using 26 mpx improves low light performance or not?

Yes, and no.

Yes: by downsampling a 61mp image to 26mp, the noise is averaged over several pixels, improving the signal to noise ratio per pixel. If you pixel-peep, the 26mp image will look better in terms of noise than the 61mp image.

No: if you print both images to the same size, the noisy pixels in the 61mp image are much smaller than those in the 26mp image. The averaging of the noise is done by the brain of the beholder: when viewed from the same distance, both images will look equally noisy (or clean). What's more, the 61mp image will look slightly more detailed.

So what exactly do you mean by improving the low light performance?

Edited April 18, 2023 by Pieter

[LCM94120]

Hi

thanks for the feedbacks.

I was thinking that some sort of onboarded technology would "merge" the pixels so that you end up like with at 26 Mpx camera, thus having bigger photosites, meaning more light per pixel.

Then apart from having less bigger files, there is no real improvement like on a real 24 or 26 mpx full frame camera I guess.

[Pieter]

16 hours ago, LCM94120 said:

I was thinking that some sort of onboarded technology would "merge" the pixels so that you end up like with at 26 Mpx camera, thus having bigger photosites, meaning more light per pixel.

It does, but what would be the practical benefit of this to you? You end up with more light per pixel (higher signal to noise ratio on pixel level, so 'cleaner' pixels) but the light per surface area of your sensor stays the same. If you print an otherwise identical 61mp image and 26mp image to the same size and view them from the same distance, you'll hardly notice any difference in terms of noise. Because the pixels of the 61mp image are really really small, and because noise is random, the brain of the viewer will average the noise much like the camera does when converting the 61mp image to 26mp. But the 61mp image does retain more detail.

So in short, yes you get cleaner pixels when the camera is set to 26mp, but you do not really get cleaner prints.

[LCM94120]

Hi

We read a lot about 24 mpx full frame sensors beeing more suited for low light capabilities where you can raise your ISOs higher and have less noise thus better image quality. Just wondered if this would have the same effect than a 24 or 26 mpx camera.