I've just seen this: Firmware Update XF300 and XF305 (http://usa.canon.com/cusa/support/consumer?pageKeyCode=prdAdvDetail&docId=0901e02480bed8fe)

Cheers

Grazie

Has anyone downloaded this yet? I'm curious as to how well the digital teleconverter works.

Hello Mark,
This is an automatic translation of my text in french.

I have installed firmware 1.0.6.0 after a repair at the front lens CANON. I see a blur important in the use of the zoom at maximum power.
I did a mail service CANON repair and I expect the answer to whether the repair is poorly done or whether firmware.
I would return to this forum after the results.

The existing 1.5x is ok as before, and the x3 is useful if you really need that much magnification. I shot some insects on flowers and with a bit of sharpening in post, it was quite acceptable. Foget entirely the x3.......