What is the "iris" of a camcorder?
A traditional iris is really just an opening, how much light is getting from the image sensor by what's called the iris, which is just the opening in between the glass and the image sensor. Now, that opening is measured in f-stops. The larger the opening, the smaller the f-stop. There are graduations in there as to what the f-stop is. You might see something like 5.6 or 11 or 16. That's really telling you how big the opening (iris) is. Now, that's important, because you obviously need a proper exposure. You need the right amount of light getting onto the chip itself. But some camcorders don't have an iris. They do what's called "electronically". They really just vary the gain or the brightness on the chip to do what an iris would do. It doesn't work exactly right, but it's how it's done in the smaller cameras. It's kind of like a television set that has a brightness control. You can turn it up, you can turn it down. It will make your picture brighter, or it will make it darker. But really, that's done electronically. So, the higher-end cameras, have the true iris in there, something that creates that opening, that f-stop, and then the less expensive cameras, although they do a great job, typically do it by varying the gain or the brightness level of the chip.
