Tom in Arizona wrote in post #18852749
Hi Rob...
Have you tried stacking the 1.4x III and 2x III using the Canon 100-400 II lens? If so, I'd like to hear your evaluation of that combination. Also, I'm new to the concept of stacking converters and don't know what the rationale is for using an extension tube. Any advice would be appreciated.
Thanks
Tom
Tom,
I looked this up on YouTube and found some information that might help you out some.
https://www.youtube.com …stacking+canon+extenders+
Just to help you out on the Canon 100-400mm vII, anything other than the Canon 1.4 extenders will not autofocus, it is futile to even try.
I have a Canon 400mm f/2.8 v1 and it will focus with a Canon 1.4x and the 2.0x, I can even shoot BiF with the 2.0x, but it is fairly slow. I use the Canon 1.4x ALL of the time on my Canon 100-400mm vII lens on my 7DmkII, it works so well that I usually leave it on. Some care for that, some don't. I can (usually) fix anything that I need in Photoshop.
Look at the video and then look at the surrounding videos there that may give you more light on this subject.
Randy