Hi people,
I was considering buying a Canon 2X converter to use with my EF100-400 F4.5-5.6 IS USM.
I plan on using it for motorcycle racing and hopefully good sunny weather.
I reilise that I could be losing auto focus if conditions are not as bright as I hope.
Just wondering if anybody has had any dealing with the converter and wishes to share experience.
Or what I'm really asking is should I buy one...

Thanks again in advance.