5D IV, 100-400 (and 70-300) with Kenko 1.4

anyone use this combination and getting over exposure by around 2 stops. Doesn't seem to over expose with the 24-104 but the 2 longer zooms its every time

Different lenses and different bodies all behave differently with aftermarket TCs. I haven't found the cause yet though. I have an older set of Kenko 1.4x and 2x, they work just fine on all 3 of my cameras and lenses, but the new YN III EF-copycat 2x over exposes on 2 of my 3 bodies with the 70-200 for example.

There are some communications going on with different cameras and these TCs that cause these problems I believe.

All 3 elements contribute to this issue, I feel. The camera, the lens and the TC...

davem01 wrote in post #18471873
anyone use this combination and getting over exposure by around 2 stops. Doesn't seem to over expose with the 24-104 but the 2 longer zooms its every time

Does it overexpose also in Live View mode ?

In my case, live vew was always correct, because a different metering system is employed in that mode. Again, the exact recipe is a mystery, but now with the 7D2 and 5D4, I run the EC down 2-3 stops, and 0 with the SL2. The YN knockoff of the Canon 2x III is very good indeed, including the IQ, so I think I will keep it despite the issues.

CheshireCat wrote in post #18471902
Does it overexpose also in Live View mode ?

ummmm. Just tried it with my 17-40 and no issues. tried the 70-300 again and around 1.5 stops overexposed, then tried it in live view. The display is ok in live view but more worryingly the shot from live view was ok as well. Not sure what to think now!