Has anyone had this problem with the Albinar lens?

There are two versions of the Albinar 500mm f8. One is a fixed aperture mirror lens and one is a variable aperture "Preset" lens.

Which version do you have?

They are both actually made by Samyang and also sold under many other names. (Opteka, Bower, Kalimar, Phoenix, Rokinon, Quantaray, Vivitar, Bell & Howell, Falcon, Walimex, etc)

These lenses are both fully manual lensese that have no communication at all with the camera.

The camera will act as if there is no lens attached to the camera. With Nikon cameras the aperture will always read F-- and with Canon cameras the aperture will always read F00.

If you have the mirror lens version the aperture is fixed at f/8.

If you have the "Preset" version you can set the aperture is on the lens itself.

The viewfinder will be slightly darker to what you are used to due to the f/8 aperture and will only get darker as you stop it down.

There are two aperture rings. The one marked "32 22 16 11 8" sets the aperture, and the one marked "O <--> C" opens and closes the aperture to allow better viewing and focusing before you stop it down to the desired aperture.

As with most lenses, this lens will give better results if you stop it down 1 or 2 stops. (f11 or f/16) This means it is best used on a sturdy tripod and/or bright conditions or high ISO.