Canon Extender EF 2x III and the 28-300L

[tlake55]

Does the new Canon Extender EF 2x III work on the Canon 28-300mm f/3.5-5.6L IS USM lens? If it does, how well?

[inkista]

The Canon 2x teleconverters will only work with f/2.8 L lenses, so no, it won't. A 2x TC adds two full stops to the max. aperture of a lens, and most Canon dSLRs stop autofocusing when the max. aperture of the lens reaches f/8, because there isn't enough light for the camera's AF system to "see" by. The f/3.5-f/5.6 of the Streetsweeper would become an f/7.1-f/11 lens.

The Streetsweeper is already seriously pushing performance boundaries to cover a >10x zoom range with anything like L quality. I don't think adding a 1.4x tc would be a good idea, let alone a 2x, given that teleconverters work better on primes than they do on zooms. The only Canon L zoom lens you might want to consider adding a 2x converter to would be the EF 70-200 f/2.8L IS USM II.

[tlake55]

Originally Posted by inkista

The Canon 2x teleconverters will only work with f/2.8 L lenses, so no, it won't. A 2x TC adds two full stops to the max. aperture of a lens, and most Canon dSLRs stop autofocusing when the max. aperture of the lens reaches f/8, because there isn't enough light for the camera's AF system to "see" by. The f/3.5-f/5.6 of the Streetsweeper would become an f/7.1-f/11 lens.

The Streetsweeper is already seriously pushing performance boundaries to cover a >10x zoom range with anything like L quality. I don't think adding a 1.4x tc would be a good idea, let alone a 2x, given that teleconverters work better on primes than they do on zooms. The only Canon L zoom lens you might want to consider adding a 2x converter to would be the EF 70-200 f/2.8L IS USM II.

How well does the 2x converter work on the 70-200L?...meaning, how crisp are the results?

[inkista]

The samples I've seen popping up on boards is pretty impressive--on a par with the 100-400L. But remember, this is only with the f/2.8 IS Mark II version of the 70-200L. With any of the other four 70-200Ls, the results won't be nearly that nice. This is undoubtedly one of the sharpest lenses Canon's ever made.