Canon Community

norrickb · ‎03-09-2023

Will this extender match with my EF 400mm 1:5.6 L telephoto lens? Will AF work? I thought the 400 mm was pretty high end expensive when I bought it, but compared to the super telephotos available now I guess it was peanuts.

Maybe I need to upgrade the 400mm?

normadel · ‎03-09-2023

Your lens is on Canon's list of lenses compatible with the extender.

BUT*******Download the manual for the lens if you don't have it. It specifically states that autofocus is not possible. Only manual focus can be used with extenders. A possible reason is that the effective maximum aperture will be reduced to f/11, which doesn't give the AF system enough light to work with.

Check the manual for any lens you want to get. It will tell you if extenders can be used.

View solution in original post

ebiggs1 · ‎03-11-2023

I'm convinced the extender isn't what I need.

Agree, it is not a good marriage. A tel-con is almost always a bad idea and or just a Band-Aid solution. Almost any native FL tele will be better in all regards. There are a few exceptions but very few and they are all the 1.4x tel-con not the 2x.

EB
EOS 1D, EOS 1D MK IIn, EOS 1D MK III, EOS 1Ds MK III, EOS 1D MK IV and EOS 1DX and many lenses.

ebiggs1 · ‎03-11-2023

"... I'll just stick with the 400 mm until (if ever) I can afford a new generation super telephoto."

Yours and everybody's best bang for the buck is one of the 150-600mm super zooms. Save up if need to and buy one of them.

EB
EOS 1D, EOS 1D MK IIn, EOS 1D MK III, EOS 1Ds MK III, EOS 1D MK IV and EOS 1DX and many lenses.

Canon Community

Extender EF 2x III Compatibility with EF 400mm f/5.6 L USM Lens