Have you captured an awesome macro photo? Post it here and share the story behind the shot. Be sure to include the Canon gear you used. This photo was captured with a Canon EOS 5D Mark III and a Canon EF 100mm f/2.8L Macro IS USM lens at f/5, 1/160 sec, ISO 100.
" Sensor is collecting light and with more pixels, each pixel is smaller and hence collects less light."
Almost perfect! 
"... each pixel is smaller and hence collects less light." Each smaller sensor collects less total light. But the light that falls on it is exactly the same regardless of its size. If you place an 8 1/2 x11" sheet of paper on the table and draw a 1" circle on it and then draw a 2" circle the amount of light falling on either is the same. However the larger circle has more of it. This again has to do with certain camera vs certain other cameras since sensor size is not the whole factor here. However, the processing hardware in the camera's electronics has a great deal, probably more, to do with how it preforms in low light or even in IQ for that matter. Again would you take a EOS 1D with a 4mp FF sensor, pixels that are huge, or a 7D with much smaller pixels to shoot low light stuff?
@ebiggs1 wrote:" Sensor is collecting light and with more pixels, each pixel is smaller and hence collects less light."
Almost perfect!
I have a problem with this analogy because it completely ignores the size of the photosites, or sensors, as well as the spacing between them. The analogy would be correct if the circle was one big photosite, but it is not. The analogy is correct about the same amount of light falling, though.
The surface of the image sensor can be compared to an ice cube tray, or a cupcake tin. Each photosite would be a “cup” in the ice cube tray or cupcake tin. Light falling on an image sensor can be compared to rainfall.
If an inch of rain falls on the ice cube tray, then every cup in the ice cube tray will collect an inch of water. Except, cups with a wide diameter, like a FF sensor, will collect more water than cups with a smaller diameter, like an APS-C sensor. Bigger cups will collect more water, and larger photosites do collect more light and smaller ones.
There is also space between the cups on the trays, just as there is space between photosites. Reducing the space between photosites increases the detail in the final image, because less light is lost to falling between photosites.
Manufacturers like to publish the size of the photosites on a sensor, but no one seems to talk about the blank space on the surface. I suppose that the amount of blank space could be inferred from the number of MP that the sensor has. But, the more completely photosites cover the image sensor, then the more detail you will get.
The ideal sensor would have large diameter photosites, which would be tightly packed together, to minimize loss of light.
@ebiggs1 wrote:" Sensor is collecting light and with more pixels, each pixel is smaller and hence collects less light."
Almost perfect!
Yes total light. I was trying to explain why the smaller pixel has more noise - I did caveat that everything else being equal - in electronics communication there's a term Signal to Noise ratio (SNR) - if this ratio is small your reception is not going to be so good - not sure if this term is used in photography but it's the same concept. Here light can be equated to Signal - amount of total light going into that pixel...the noise is the same regardless of pixel size for a certain sensor. So for smaller pixel that receives less total light, the SNR is smaller compared to a larger pixel - quality will be worse than a larger pixel.
