Subsampling is how. Camera does its "thing." Well beyond my expertise or even desire to understand. Bit depth or color depth is a bit easier to manage and makes my life much better the more I have
. Adobe actually has a decent explanations but because Steve has a nifty anti-spam policy, I can't post the links so I'll copy/paste:
"Color depth (or bit depth) is the number of bits per channel (bpc) used to represent the color of a pixel. The more bits for each RGB channel (red, green, and blue), the more colors each pixel can represent."
"Bit depth specifies how much color information is available for each pixel in an image. The more bits of information per pixel, the more available colors and more accurate color representation. For example, an image with a bit depth of 1 has pixels with two possible values: black and white. An image with a bit depth of 8 has 28, or 256, possible values. Grayscale mode images with a bit depth of 8 have 256 possible gray values.
RGB images are made of three color channels. An 8‑bit per pixel RGB image has 256 possible values for each channel which means it has over 16 million possible color values. RGB images with 8‑bits per channel (bpc) are sometimes called 24‑bit images (8 bits x 3 channels = 24 bits of data for each pixel)."
Chromo subsampling is how the camera takes this info off the sensor