Explore Scientific Focal Extenders and TeleVue Powermates are examples of Telecentric lenses. Photos are not to scale.
Most of us have been there. You want more magnification then your lowest focal length eyepiece can give so you turn to a multiplier. But wait – Barlows, Powermates, Focal Extenders? Are these interchangeable in use? If not, how do they behave differently at the eyepiece?