My new Kenko Pro 300 DG 2x Teleconverter arrived today, not bad seeing as I only ordered it Monday night, and it came from Hong Kong. It also escaped duty and VAT so only cost me £75.
Having had a quick play with it on the 70-200/2.8 it seems to work very well, I had intended to get a 1.4x as well at the end of the month but I might give that a miss for a while having seen the results from the 2x.
Having done some testing, it also works quite happily on my 24-70/2.8, 50/1.8, and 90/2.8 Macro. Whilst it fits the 10-20/4-5.6, the camera won’t then autofocus correctly which isn’t really a surprise.
Hopefully this will satisfy my desire for a longer lens for a while.