5D Mark III -- Autofocus at f/8! Sort of...

[Alan Stankevitz]

Got my 5DM3 today and have been running it through its paces. Just for kicks, I threw on a Tamron non-reporting 1.4x TC on my 600mm with another 1.4X giving me a focal length of 1176mm @ f/5.6 (at least that's what the 5DM3 thinks. It's actually f/8, but since the non-reporting teleconverter isn't seen by the 5DM3, it thinks it's f/5.6) And???

It autofocuses w/o hunting like crazy. It's a tad slower and jitters on occasion, but it's definitely useable. I have yet to try it on BIF, but I'm quite certain it should work reasonably well.

Besides, the 600mm @ /f.8, I tried the non-reporting TC 1.4x on the Canon 400mm f/5.6 and the Canon 100-400 f/5.6. Both are useable!

Here's a sample I took at the peanut feeder this afternoon under dark and gloomy conditions (Canon 600mm + 1.4x + 1.4x, Canon 5D Mark III, ISO 1600, 1/640 sec):



The 5DM3 autofocus is excellent!

Alan

[Ofer Levy]

That's fantastic news! I guess it will work with the Canon converters with one of the pins covered.

[mikeojohnson]

I'm curious as to the model number of the Tamron t/c
thanks,
mike

[Alan Stankevitz]

I'm curious as to the model number of the Tamron t/c
thanks,
mike

Model 1.4x C-AF1 MC4