Originally posted by WMBP I am not sure I understand the technical difference between extension tubes and teleconverters. I have a 1.4x Tamron teleconverter that I use with my 70-300mm zoom lens. What difference would an extension tube make, if any?
Will
Teleconverters increase the effective focal length of the lens and contain lens elements to achieve this.
Extension tubes are exactly that: devices for positioning the lens further from the sensor to enable closer focussing. The have no lenticular elements.
There have been a few variations on the theme. I recall one, by Tamron I think, which was a teleconverter with a removable lens element group which left the empty body to be used as an extension ring.
HTH