Extender for Canon EF 28-135mm f3.5-f/5.6 IS USM

Having recently broken my 70-300mmm lenz I need a zoom but will have to save my pennies for the 70-200 L lenz I would like.

In the meantime can I get an extender for my Canon EF 28-135mm f3.5-f/5.6 IS USM that will so me through the next fews weeks?

Which body are you using? The reason I ask is that you probably won't get AF even with the 1.4x Kenko with your lens with anything short of a 1D series, not to mention, Kenko advises against using it with focal lengths wider than 50mm. If you use it, I suggest only using it from teh 50-135 range. The Canon for sure won't work since it won't mount, it will bump into the rear element of your lens.

Oops!

30D body

Remember you will lose one stop with the 1.4x and 2 for the 2x. With the Kenko and my 70-300 IS @ f/5.6 which is actually f/8 I can only get the center focus point to work.
However, with the 70-200 f/4 which is f5.6 with the converter, I can get all points working. But I've read that since the AF is better, more sensitive with less light on the 1D series bodies, this shouldn't be a problem.

I've never tried this before so I just popped outside with my wife's 350D, Kenko 1.4 and the 28-135.

I was amazed to get centre AF at max zoom up to f/11...no hunting, nothing.
Trying again in a lower light situation..under the trees...I lost the AF above f/5.6

It looks to me that it's workable in good light and high contrast despite what the spec's say....it amazed me!

Bob