Canon extender 1.4XII compatible with 100ISL Macro?

[NigelC]

Supposedly, 1.4X should only be used with fixed focal length lenses 135mm and over. has anyone used with 100L macro? Would any problems be mechanical or IQ ones? I don't mind experimenting on the latter, but not the former.

[francois]

No, it's not compatible. The rear element on the 100 L and the front element on the extender make it impossible.

[NigelC]

I have picked up elsewhere that it will work if the 12mm extension tube is used in between.

[stever]

if you need the magnification, you can put a 12.5mm extension tube between the lens and extension tube

some of the 3rd party extenders work, i have a Kenko pro which is not as good as the Canon and doesn't do the lens justice

[francois]

I have picked up elsewhere that it will work if the 12mm extension tube is used in between.

Yes, that's true. I don't know how's is the IQ with this setup, though.