Bigger file noise advantage?

[jaomul]

Hi All,

while reading a few reviews I saw a comparison between 2 camera sensors that stated that though the noise levels looked very similar at similar iso levels, the larger megapixel sensor would show an advantage in the finished image. Why so? Thanks

 

[Propsguy]

Probably higher resolution.

 

[KmH]

Likely because of in the camera software.

Two image sensors of the same size having different MP counts means the image sensor with a higher MP has smaller pixels than the other.
As pixels get smaller they have a lower SNR (signal to noise ratio) because each pixel captures fewer photons (light).

That's a main reason why full frame image sensors generally have better high ISO performance than APS-C and smaller size sensors do. The full frame image sensor pixels are several times larger and have a better SNR.

File size isn't the same as image size, or more accurately image resolution whjch is the pixel dimensions of the image.
Altering the image file size would effect the image quality but would not directly effect any noise in the image.

 

[Trever1t]

a 36mp sensor may give similar noise levels at a given ISO as a 12mp sensor but when printing both at 8x10 or whatever you are normalizing the 36mp file to the 12mp size and indeed going to show less noise as a result. Or if you tried to print the 12MP file at say 24x30 you'd see higher noise from the 12mp file.

 

[Derrel]

Somebody once said, "Bigger is better." This article might be helpful for increasing understanding. Full Frame Myth

 

[jaomul]

Somebody once said, "Bigger is better." This article might be helpful for increasing understanding. Full Frame Myth

Thanks Derrel. This is not exactly what I was looking for. It is not overly important but to explain better what I meant- in dp reviews Nikon d7100 review under the noise section it says with no nr the d7100 looks pretty similar to the 7d at same settings, but that the Nikon should have the advantage due resolution. I was just curious as to why

 

[KmH]

Where does the Nikon D7100 DP review say that?

I found: http://www.dpreview.com/reviews/nikon-d7100/13

In Raw mode, the D7100 displays noise levels consistent with its APS-C competition. However, since this is a per-pixel test, which would usually be a disadvantage for high pixel count sensors, its ability to produce the same per-pixel noise as the EOS 7D is impressive (since it means it'll produce lower noise if assessed at the whole image level).

 

[jaomul]

Read the last line. Does that not say it will produce less noise if you assess whole image. I could he understanding this wrong