70-300L + Kenko 1.4 + 60D = ?

Has anyone tried the 70-300L with the Kenko 1.4x Pro 300 DGX on a 60D? How is focus using center point? There are a couple of times where I may want that extra reach, like later this summer I'll probably be in a high rise in Chicago watching the Air and Water show, but it is pretty far from the water front.

However good a lens the 70-300 is I can assure you that it does not take well to a converter unfortunately, you will experience excessive focus hunting even in good light, I gave up trying to use this same combo even on a 1D.

with this combination the max apeture does fall to f/8, but in normal daylight conditions it acquires focus normally on the 7d center spot, although it's slower

just tested it indoors it still focuses down to ev 9 or 40 lux, which is iso 3200, f/8, 1/8th of second, using the Kenko pro dgx 300 1.4x converter.

Cassiedup wrote in post #14679793
However good a lens the 70-300 is I can assure you that it does not take well to a converter unfortunately, you will experience excessive focus hunting even in good light, I gave up trying to use this same combo even on a 1D.

same experience here....