Bias frame

Okay kiddo, so you know how when you take a picture, sometimes it can look lighter or darker than it actually is? That's because of something called "bias," which is like a little error that happens in the camera.

A "bias frame" is basically a special picture that the camera takes before it takes the real picture. It doesn't have anything in it that you want to actually take a picture of - it's just a blank, dark picture. But this blank picture helps the camera figure out how much bias there is, so it can fix it when it takes the real picture.

It's kind of like when you're painting a picture, and you test out your brush on a scrap piece of paper first. You don't really care about what the scrap paper looks like, you just want to make sure the paint is going on the way you want it to. A bias frame is like a camera's version of a scrap piece of paper - it's just a test to make sure the real picture comes out the way you want it to. Does that make sense, kiddo?