R5 Mark II + "Detect priority AE while AF"

[thegios]

Apologies, I've tried asking this before, but haven't got a clear answer yet, so I'll try asking again...

Part 1

Is it true or not that Evaluative Metering considers the whole scene but with a bias on focusing point? I am asking because this is not documented on Canon manuals but many photographers say so. This is also supported by Canon manual (thanks Canon for making things ambiguous) in the AE Lock description: in Evaluative Metering the AE Lock considers the point in focus.

Part 2

If we all agree that Evaluative Metering is biased on point in focus , then what is "Detect priority AE while AF" for? This is a new option introduced with R5Mk2 and works only under two concurrent conditions: Evaluative Metering + a SUBJECT is in focus, where subject is a person, an animal or a vehicle. SUBJECT is key here, because for "Detect priority AE while AF" a chair in focus or a house in focus or a tree in focus is not a SUBJECT.

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So, given we are in Evaluative Metering, I'll try to give my interpretation of three possible scenarios, based on some tests:

1. "Detect priority AE while AF" is OFF: metering considers whole area with a bias on point in focus.

2a "Detect priority AE while AF" is ON + no SUBJECT in focus: same as 1 (metering considers whole area with a bias on point in focus.)

2b. "Detect priority AE while AF" is ON + SUBJECT in focus: metering considers ONLY THE SUBJECT, not the whole area with a bias on the SUBJECT but ONLY THE SUBJECT, that is a sort of spot metering on the SUBJECT in focus.

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What do you think?

[p4pictures]

The part…

Especially if you consider "AE lock meter. mode after focus" and you have BBF and you always use servo...

This custom function is applicable ONLY when one shot AF and evaluative metering is used. Since the dawn of the EOS system, Canon have linked one-shot AF focus complete signal with exposure lock. The idea being that with one shot AF, photographers focused on a subject then recomposed the frame, so it makes sense to bias the exposure to the AF point and lock the exposure in that case. Since around the EOS 6D DSLR the custom function was added to allow photographers to have the same automatic exposure lock with one shot AF for any of the metering patterns. Such an approach is mostly helpful if a photographer uses the central AF point and say spot metering as this only measures from the centre. Without this custom setting, they would focus, lock the focus, recompose and the metering was now pointed at a different part of the scene. 

This function is independent of BBF or shutter button being used, and completely irrelevant if you use Servo AF since there is no "locked" focus signal from servo AF. 

[Waddizzle]

Totally agree, Brian