When a camera says that it has, for example, a 10x optical zoom, what exactly is that 10x based on? Is it the angle of view of the human eye, the focal length of the camera, or what?
On every conventional digital camera (excluding the models with detachable lenses), there are buttons to zoom in and out with W side and T side. When you press W, the lens zooms out. The lens zooms ...
I would like to know why motorized zoom (controlled by a W/T lever) is always on fixed-lens cameras and never on interchangeable lens cameras.
I have Canon 18-135 and 70-300 zoom lenses. People ask me how much zoom my camera supports. What am I supposed to tell them? "135 ÷ 18 = 7.5" and "300 ÷ 70 = 4.2"?
How can a lens have a range of focal lengths? Shouldn't it be a single number? Isn't focal length supposed to be fixed for a lens of a particular shape and geometry? What am I missing? How many ...