Hi Julian

I noticed on your jlcalc app that adding teleconvertors to extension
tubes does not affect the minimum and maximum focusing distance. In my
experience, the mfd DOES change when a TC is placed in front of
extension tubes. I can work around the problem by just typing in the
extended focal length into the focal length field, and leaving the
teleconvertor field blank, but I thought you might want to fix it.

Cheers,

--
Brendan Simons, Project Engineering
Stern Laboratories, Hamilton ON
905-548-5322, www.sternlab.com