18 mpixel sensor pixel size vs older types

redguy22 wrote:

Heya folks,

I just came across some info how big pixels are on different cameras and sensors. And noticed that my old (But still decent) Canon EOS 1000d/ Rebel XS has a bigger pixel size, but less megapixels.

The new 18 megapixel sensors on the 600D/700D/100D(T3i/T4i) have obviously more pixels, but are abit smaller. 5.7µm on the 1000D vs 4.3µm on the 700D & co.

Pretty curious how this affects the quality of pictures. From what I understand so far the 1000d should perform a bit better on the noise part (minus the noise reduction settings) but the 700D & co should perform a bit better on daylight scenes.

Just trying to understand sensor mechanics a bit. And trying to see if Canon sacrifices noise performance for more megapixels.

Or I am just plain wrong on everything, oops? but, I'm happy to hear the correct info in that case.

I think the whole "bigger pixels = less noise" rule is only applicable when comparing sensors built with similar technology. The 1000D came out back in mid-2008, whereas the 600D came out in early-2011, and the others after that. I would assume that fabrication/process/technology had advanced in the intervening 2.5+ years that allow lower noise in the smaller pixels.

If physical pixel size is the only factor that affects noise, then there would be no difference in noise performance between camera models, and that is not at all the case. We'd also probably still have low-MP cameras around specifically for people who want low-noise performance, and this is also not the case.