Interesting Wayne. It was not mentioned in John Shaw's books, IIRC that using
a TC can result in a focal length at closest focus shorter than the primary
Very weird. It get's a bit complex adding extension before or after the TC as
well but it had been assumed by many that a 2X TC on a 50mm lens right on the
lens with no ext tube
would largely behave as a 100mm lens ---well at infinity, it does.
TC even back in the day work best with matched optics---now essentially
critical with all the aspheric elements.
I remember my first trial using a Tamron 2X TC on the Zuiko 50mm/3.5 macro.
Ugh!! -- the corners were mush even stopped down a bunch. Same TC on the Tam
80-200/2.8 worked nicely.
Just have to try it sometimes and see what happens, Mike
Themed Olympus Photo Exhibition: http://www.tope.nl/