R5 Mk2 : detect Priority AE with AF

[thegios]

There's a new option on R5 Mk2 named "Detect Priority AE with AF" AKA "AE for priority subjects during AF".

This works only under two conditions:

- EVALUATIVE

- SUBJECT DETECTION ON (either auto or vehicles or people or animals)

Before moving forward with questions on this new setting, let's first sort out one thing with EVALUATIVE: where is the exposure taken in EVALUATIVE?C anon says that metering considers the whole area, fine we all know this. But Canon also says that in EVALUATIVE the AE lock is centered on the AF POINT in focus (either selected manually or automatically).

That's why lots of people say that EVALUATIVE considers the whole scene but is weighted more on the point in focus.

What is the truth?

This is important to answer the following question:

What does the new option do?

Since I make a difference between POINT IN FOCUS and SUBJECT IS FOCUS (where a SUBJECT, according to Canon settings in SUBJECT TO DETECT, is a person or an animal or a vehicle, not a chair, not a table, not a column), from what Canon writes I understand that in EVALUATIVE:

- off > metering based on whole screen

- on > metering based on DETECTED SUBJECT, so if there's none (no people, no animals, no vehicles), even if focus is on a chair, than metering is based on whole screen. But then, what about Canon saying that AE lock is achieved at POINT IN FOCUS? And also, if there's a DETECTED SUBJECT IN FOCUS (a vehicle, a person or an animal), does this mean that you get exposure considering only the subject or metering is still based on whole area but weighted more on the subject?

My interpretation:

- OPTION OFF + SUBJECT TO DETECT ON or OFF: metering considers whole area but is weighted more on POINT in focus.

- OPTION ON+ SUBJECT TO DETECT OFF: metering considers whole area but is weighted more on POINT in focus (like above).

- OPTION ON + SUBJECT TO DETECT ON: metering considers only SUBJECT in focus.

Anyone who can shed some light?

[Waddizzle]

 “ 

This makes sense, although Canon doesn't explicitly say that evaluative weights more the AF point(s) but says that AE Lock is centered on the points in focus. Reason why this new "detect Priority AE with AF" sounds strange. “

• That phrase is exactly why I suspect it is referring to a detected subject. Multiple AF points can be in focus on a subject at any given moment.  But only one is used to lock focus when the shutter fires.  
  
  This is some random photo I found of the Canon AF display..

The AF has found the face within the large bounding rectangle. This large box can change shape and size as needed. 

Within the box there’s an AF point that has locked focus on the eye. Conventional Evaluative Metering mode  would use the eye area to bias the exposure.  It seems like Priority AE uses a larger area, possibly the bounding rectangle.  

[Waddizzle]

This makes sense, although Canon doesn't explicitly say that evaluative weights more the AF point(s) but says that AE Lock is centered on the points in focus. Reason why this new "detect Priority AE with AF" sounds strange. “

• That phrase is exactly why I suspect it is referring to a detected subject. Multiple AF points can be in focus on a subject at any given moment.  But only one is used to lock focus when the shutter fires.  
  
  This is some random photo I found of the Canon AF display..

The AF has found the face within the large bounding rectangle. This large box can change shape and size as needed. 

Within the box there’s an AF point that has locked focus on the eye. Conventional Evaluative Metering mode  would use the eye area to bias the exposure.  It seems like Priority AE uses a larger area, possibly the bounding rectangle.  

[thegios]

I had to buy Nina's book for R5 MK2 to find the answer 🙂

"The advantage given by tying this into the Subject to detect system is that it can more accurately gauge what is the subject and what is the background and  therefore can correct for more significant exposure errors, resulting in the exposure compensation system needing to be used significantly less of the time.

By default the camera is set up to have this feature Enabled, so the main exposure is always going to be concentrated for the main subject, providing of course that the Subject to detect system is working.

How much difference you see between the two settings is going to change according to the type of lighting you are shooting with. In front lighting where the subject is evenly lit, you may not see any difference at all between the two options.

When you are shooting with strong side lighting or particularly strong backlighting, it will give much greater variation between the type of image that you are capturing. When the feature is enabled, the exposure will be far more biased on the subject"

[Waddizzle]

“ The advantage given by tying this into the Subject to detect system is that it can more accurately gauge what is the subject and what is the background and  therefore can correct for more significant exposure errors, resulting in the exposure compensation system needing to be used significantly less of the time. “

Sounds like my guesses and assumptions were close to spot on. It evaluates a larger area defined by the subject detected.  That bounding rectangle I was pointing out.

[thegios]

Yes.