I came across a store selling telescopes as camera lenses. It's reflector telescope designed to be used with cameras. Doesn't have an eyepiece, doesn't attach to a tripod. Does attach to a camera, does have a focus adjustment, marked with distances. Looks like this: A Canon 300mm lens is $4000 US, that's f/4, IS Image Stabilization, USM focus motor. A Canon 500mm lens is $5700, an 800mm lens is $11,000. That's more than my motorcycle! My lens cost me $135, including shipping and border fees. At that price, you sacrifice a few incidentals, such as IS Image Stabilization. You don't get a focus motor, you have to focus manually. You don't even get an aperture, to reduce the light you have neutral density filters which cut the light be 2 and 4 f-stops. No, the filters don't go on the front, you have to take the lens off the camera and fit them on the rear. As for the focus, you have to get it dead right. At a distance of 12 feet, you get a depth-of-field of