I use the FA *200/2.8 with the 1.4XL converter. It works pretty well.
Thanks for the information Bruce, I take it that with the 1.4XL you will lose just one stop, which I assume makes the lens an f3.5.
f/2.8 - 1 stop = f/4
or even more simple (?):
2.8 * 1.4 = 4
and
200 * 1.4 = 280
DagT
