[graham catley]

A challenge for the first recipients of the new lens;; with the 2x converter mark 3 is it a viable replacement for the 500f4 re AF speed and IQ ? many of the people now with bad backs and 500's I am sure will be interested;

old 300 2.8 II and 2x mark 3 this morning below

[Jaff]

Originally Posted by graham catley

A challenge for the first recipients of the new lens;; with the 2x converter mark 3 is it a viable replacement for the 500f4 re AF speed and IQ ? many of the people now with bad backs and 500's I am sure will be interested;

old 300 2.8 II and 2x mark 3 this morning below

I'd be pretty certain that a straight f4 will always be noticeably quicker AF-ing than anything at f5.6 regardless of what kit was actually involved, even if it's the latest and greatest. I would argue the same with regards to IQ too but I obviously can't say for certain not having tried the new 300mm and only having had brief goes with a MKI 500mm.

If you meant the 500mm with a 1.4x on then that'd be a different kettle of fish.

Your last sentence is a little confusing though Graham, 'old' 300mm f2.8 II?

[graham catley]

Yes I confuse myself at times. Current 300 2.8 and 2x mark 3 should be more accurate. I was wondering if he claimed increase in af speed and extra IS one the new 300 with converters would equal the old 500 with or without converters: its weight and convenience and versatility v reach really. Anyway no sign of any new models appearing yet anyway so its all speculative for a few more months / years?