extender 1.4 and Canon 17-40 f4L

[cyben]

Hello,
Is it possible to use an extender on a 17-40mm and a 1.4 Extender on a Canon 20D and if so will I lose a lot of image quality.
I have a 17-40 and a 70-200 f4 L ut nothing in between and I do not want to get another len is it is possible.I had the 17 -85 IS but was quite disapointed.
Thanks

[ddelallata]

the 1.4 is not intended for lenses like the 17-40. There's a sticky here somewhere with more info about this. It''ll work great with your 70-200 though.

[rent]

some third party TC's will work with the 17-40. you will definately lose image quality when a TC is used. -alex