Canon EOS R6 Mark II work with Speedlite EL-5 problem

[Ccming]

I use Fv with auto ISO, auto aperture, auto shutter speed and ETTL flash.

before Feb, include Feb, the auto f stop can be correctly set as f2.8 automatically.

but from Mar, it always set f4 as priority, and ISO often go to 6400.

today, 2024-Aug-07, I went to a shop to try another two R6 Mark II,

what I found is, if the firmware version is 1.1, auto aperture works normal, but if the firmware version is 1.4, the auto aperture will be f4 for most of the situation, except very low light, it can be f2.8

[kvbarkley]

What is the problem?

[deebatman316]

It was common for DSLRs when set to P or A+ Modes. To set exposure settings to 1/60th F/4 ISO 400. If the lens had a maximum aperture of F/5.6 it would just change the aperture to that. But the camera uses Fill Flash in those modes. So all the camera did was adjust flash output in E-TTL Mode regardless of the aperture set.