EOS R5 Mark II: BBF and AE Lock

[thegios]

I have triple BBF configured

- SHUTTER: Metering Start
- AF-ON: Metering and AF Start
- *: Metering and AF Start but with subject detecnion OFF
- FOCUS POINT SELECTION: Af with eye control

How do I lock exposure now?

I am asking because people keep on telling me that by half pressing shutter the exposure is supposed to be locked, but this is not the case in any metering mode and/or shooting mode and/or focusing mode.
Thx

[thegios]

After some tests, probably I have an answer to QUESTION 2: metering is taken at center on the subject, but when the subject moves the focus is still on the subject but metering is still taken at center and as a matter of fact changes whiel subject moves off center

I still don't have an answer to QUESTION 1

[p4pictures]

For your QUESTION 1

The new ability in the EOS R5 Mark II to choose to bias the evaluative metering to the subject or not works like this. 

The camera must be set to evaluative metering, subject detection cannot be set to NONE

In such case the detected subject in the frame will be the most important part for the exposure system, even if other parts of the frame are in-focus but not a subject. You can imagine a person stood in a doorway, the face is the important subject, even though the door frame is also in focus.

When Detect priority AE while AF is off, then all the in focus AF points are considered as being important areas for the metering. This is also the effect when subject to detect is set to none. 

Hope that helps.

[thegios]

This helps indeed, because I had the same interpretation: to me there is a distinction between SOMETHING in focus and a SUBJECT in focus, where SUBJECT can be a person, an animal or a vehicle. I had dis discussion with someone else in an other forum who would say: why a chair in focus should not be a SUBJECT, and to me the reason is that otherwise Canon would not have made a menu option for SUBJECT detection on/or where you have a limited list for subjects (person, vehicle, animal).
So according to waht you say:

• EVALUATIVE + "Detect priority AE while AF" ON + "Subject to detect" ON: metering on SUBJECT
• EVALUATIVE + "Detect priority AE while AF" ON + "Subject to detect" OFF: bias toward whatever is on focus
• EVALUATIVE + "Detect priority AE while AF" OFF + "Subject to detect" OFF or ON: bias toward whatever is on focus

[p4pictures]

Agreed that's how I read it. 

And for good measure when you use the AF areas with the padlocks they force subject detection to none and also whole area AF tracking off, so this setting is not relevant for them either.

[thegios]

"when you use the AF areas with the padlocks"

What do you mean here?

[p4pictures]

The EOS R5 Mark II has four additional AF areas each with a padlock in the lower right corner. 

Check the second screen illustration on this page of the EOS R5 Mk2 manual

https://cam.start.canon/en/C017/manual/html/UG-04_AF-Drive_0060.html 

These "padlocked" AF areas also force subject to detect to none and switch off whole area AF tracking, so that these areas will work the same as the ones in the original EOS R5. But since they have no subject then the "Detect priority AE while AF" setting is not used, simply the active focus points.

[thegios]

Oh yes yes, I know... Apologies but couldn't associate "padlock".

Thanks again

[jeffn54]

I have not tried the specific configuration of the BBF button you have defined here. But, I found in most if not all cases I can lock the Exposure with the * button on the back.

[p4pictures]

You are correct that the * button locks the exposure normally on most cameras.  However the OP mentioned that they had reconfigured their * button to work as an additional focus button with different settings to the AF-ON button, and in-doing so needed a different way to access the AE-lock function.