I decided to try out some extreme telephoto optics: my longest fixed telephoto lens is the Canon 300mm f/2.8 IS and it is a very sharp lens, and I decided to put a Kenko 1.4x teleconverter together with a Canon 2x TC with this lens on my Canon 1D Mk III camera. This combo adds up to an 840mm equivalent focal length (before factoring in the 1D 1.3 "crop factor"), but at the cost of sharpness.

I happen to value max sharpness, which is why I've never tried this combination, but my hopes of getting a 500mm or 600mm fixed lens this year seem to be distant, so I went ahead and put this combo together and headed down to Critter Lake, my nearby wetlands, to test it out, wanting to get a feel of it heading into the Fall birding season. Fortunately, there were a few ducks around, a hawk graced me with its presence, a couple pidgeons and a scrub jay.

I took all these shots with my gear perched on the car window (engine off, padded with a jacket). As I expected, not as sharp as I normally insist on, but my hopes are that as I carefully work with this combo, I will get "acceptable" shots that would otherwise be too distant!

I have accompanied each of my shots here with close crops, because 1)This is how we show bird shots and 2) I want to show the relative sharpness of these shots. I'd like people to respond -- does the loss in sharpness outweigh the gain in reach? Input is appreciated!