70-200 f/4L + 2x Extender?

Has anyone hear used a 70-200 f/4L with the canon 2x Extender?? I have been looking into this as an alternative to getting a whole new lens and was wondering what peoples experiences were with it. Would like to know specifics such as how the IQ, image quality, aperature, noise, and other things changed with the addition of the extender. BTW it would be used on a 40D Any help would be great!!
Thanks

First off you will lose AF. IQ will suffer greatly. But, overall it isn't too bad really. Real solution is to get a longer lens though. What are you trying to take pix of?

KJEphoto wrote in post #6853290
Has anyone hear used a 70-200 f/4L with the canon 2x Extender?? I have been looking into this as an alternative to getting a whole new lens and was wondering what peoples experiences were with it. Would like to know specifics such as how the IQ, image quality, aperature, noise, and other things changed with the addition of the extender. BTW it would be used on a 40D Any help would be great!!
Thanks

I used this combo when shooting the open national stunt glider championships a few years ago, because I needed a long lens to do so. This was the direct reason for getting a 100-400L, after having tried a few other options as well.

The 70-200 is great with a 1.4X extender, but not with a 2X. Losing AF and a lot of IQ is not going to make you happy, IMO, especially not when you're used to the quality you get out of the "naked" 70-200 in the first place.

Kind regards, Wim

KJEphoto wrote in post #6853290
Has anyone hear used a 70-200 f/4L with the canon 2x Extender?? I have been looking into this as an alternative to getting a whole new lens and was wondering what peoples experiences were with it. Would like to know specifics such as how the IQ, image quality, aperature, noise, and other things changed with the addition of the extender. BTW it would be used on a 40D Any help would be great!!
Thanks

Image quality suffers quite a bit. It's still 'OK', but that's not why you bought an 'L' lens!
Aperture is degraded 2 stops so it becomes an f/8 lens, and probably needs stopping down another one for acceptable quality.
Noise is unaffected - that's not a lens issue.
As others have said, you'll lose auto focus on a 40D.
All in all I'd say you're better off with a 1.4x teleconverter and cropping the image if you need to...