Canon EOS 2x extender

[jamisan]

Anybody ever use one and how good are they really?
Thanks

[Bob Atkins]

See http://www.bobatkins.com/photography/reviews/tcs.html and http://www.bobatkins.com/photography/tutorials/tc3.html

With a good lens ("L' series telephoto) a 2x TC can be useful. Sharpness drops, but if you really need to extend the focal length, you have to accept that. The 1.4x usually gives better image quality.

[jamisan]

After I posted this I did some research on the 1.4 sounds like that would be the one to get. I know I wont gain much but does anyone know if this (the 1.4)will work with the 28-135mm IS USM? (have one) I can probably afford the extender but cant afford an L telephoto right now.

[Bob Atkins]

The Canon 1.4x will not fit, but the Tamron 1.4x will. That's the 1.4x extender that I use with lenses that won't take the Canon TCs.

You may or may not get good AF operation since the 28-135 is slow (f5.6) at the long end. However even if you have to use manual focus, it's fairly easy with that lens which has a good manual focus system, and the AF confirmation light (and beep) will probably operate OK.

[jamisan]

Will the Tamron  1.4x Teleconverter work on the Canon 70-300 IS USM 4-5.6? 

[Bob Atkins]

Yes, I use one on mine. You won't get autofocus, but IS will work just the same.

If the light is OK and you have resonable subject contrast, the "green dot" focus confirmation indicator in the viewfinder may work when you're using manual focus with this combination.