Thanks John, Kurt, Rex... much appreciated
I have two Sigma lenses at this time; the 105/2.8 Macro & 135-400/4.5-5.6 APO... and I'm not thinking of getting any other Sigma glass.
My other lenses are;
Minolta 50/1.7, Minolta 100/2.8 Macro, Minolta Mirror 500/8.
Tamron 17-50/2.8, Tamron 28-300/3.5-6.3 and Tamron 11-18/4.5-5.6.
Sony glass; DT 1650/2.8, DT 30/2.8 Macro, DT 55-200/4-5.6, DT 18-70/3.5-5.6 (came with the a700), 70-400G/4-5.6 - and I'm not counting the 70-300/4.5-5.6 'nicked', 'borrowed' by the lad!