sigma and Kenko 2x converters for canon

[stewie m]

how do theses cope with auto focus and ai servo modes on a canon with a sigma 150-500mm

 

[twist]

Sigma 150-500 wont AF at all with a 2x

 

[seriousrikk]

In fact, it won't AF very well with an converter.

The canon camera you have requires an aperture of F5.6 or wider in order to autofocus.

Sure, the Kenko 1.4x 300 dgx does not disable AF - but your max aperture would be F9 which would need excellent light and a high contrast subject to work on one shot. AI servo would be... disappointing.

a 2x would be F13 or thereabouts - defiantly not.