Any one had the issue of a Kenko Teleplus mc4 DGX (1.4x telecon) locking up their camera when used with specific lenses? It works fine with 5d3 plus most of my lenses, but when used with my 400 f5.6 it autofocuses (this tc doesn't have the pins which prevent af @ f/8) and meters correctly, however when I take the shot the camera locks up with the shot counter blinking, and I have to pull the battery to restore function. If there is no solution I will return the tc, as I bought it with the hopes of af at f/8 on my 400 mm, and already have the canon 1.4x II.
