18 mpixel sensor pixel size vs older types

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.

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.

Also, assuming max ISO is an indicator of sensor noise performance, the 600D has 2x the ISO, and the 650D and later have 8x the ISO performance of the 1000D.

Try going to a dpreview camera review, such as http://www.dpreview.com/reviews/canon-eos-650d-rebel-t4i/25 and use the compare tool to directly compare the noise performance yourself.

Very simply: more pixels means more sharpness (all else being equal).

A larger sensor means less shot noise (all else being equal).

Changing the number of pixels that a particular size of sensor is divided into doesn't affect shot noise levels. If you zoom into the pixel level, then yes, you'll see more noise. But that's because you're zoomed farther in. At a given image size, the amount of shot noise is constant no matter how many or how few megapixels are present.

That said... "all else being equal" is rarely true. You have to evaluate each camera model on its own merits. You can't determine image quality via calculations. You have to take pictures and look at them.

seeker moc wrote:

Also, assuming max ISO is an indicator of sensor noise performance

My general view is that max ISO is an indicator of what the marketing department wanted this year

Hello.

As others mentioned, it all depends. But with higher megapixel count sensor, you definitely get more resolution and sharpness, very well usable at moderate to low ISO settings.

I see that DPR didn´t have that nice viewing engine of their test shots, so you can´t directly compare noise of your 1000D and newer cams. So I tried to do the same cut-out of these test shots and compare it to the old picture (downsize). Here you can see result:

ISO1600 - leftside = EOS 1000D, middle = EOS 1100D, right side = EOS 100D

As you can see from that ISO1600 image comparison (with pixel peeping), with higher pixel number you get less image noise here, because newer cameras are just better. You will get the same or more noise at pixel level, but definitely not on picture level. Don´t worry, go for 18Mpx cam. Hope Canon will soon manage to (let us) use their dualpixels sensor cams as single pixel so we could have 36Mpx in APS-C sensor. WOOOW