Sony A7RIV - About diafragma and shutterspeed

[todegro69]

I have the Sony 24-105mm lens on my SonyA7RIV. I am in A modus. Diafragma is fixed to 4.0, time is 2.5" and ISO is 100. When I move my camera around these settings change depending on the ambient light. When I point to the window the shutterspeed changes to 1/200". This seems very logic.

When I press AF-ON (which is set to BackFocus) shutterspeed changes to 1/320" and only when I push to take my picture I see the ISO changing from auto to 400. Is this the normal way things happen?

So I have to focus before I can see if my shutterspeed is OK and my ISO is not too high?

Thank you for your reply

[Joe_Dohn · Accepted solution]

According to the Help Guide for the camera, in Aperature priority (dial mode A), this is how things are handled.