topic Re: R5 Mk2 : detect Priority AE with AF in EOS DSLR & Mirrorless Cameras

R5 Mk2 : detect Priority AE with AF

thegios — Sat, 07 Sep 2024 14:33:04 GMT

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?

Re: R5 Mk2 : detect Priority AE with AF

John_Q — Tue, 10 Sep 2024 00:21:44 GMT

Hello thegios,

Evaluative metering is a general purpose metering mode using the entire scene. The camera adjusts the exposure automatically to suit the scene. The AE Lock feature is going to keep shooting at the same exposure. The camera will use the AF point in focus for exposure when you press the AE Lock button. If the AE Lock button is not pressed, then it is possible that the exposure can shift from shot to shot. The camera uses the point in focus as reference based on your shooting at that item/subject.

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

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

- OPTION ON + SUBJECT TO DETECT ON: metering is based on the point or AF area where the subject has been detected.

If there is a subject detected with the [Detect priority AE while AF] set to [Enable], metering will be based specifically on the AF point or AF Area where the subject has been detected.

Re: R5 Mk2 : detect Priority AE with AF

thegios — Tue, 10 Sep 2024 06:34:32 GMT

Ok so let me try to rephrse and add a couple of clarification questions, please:

QUESTION 1: when you/manual says SUBJECT IN FOCUS, are you/manual refering only to people/animals/vehicles? Or said in other words: if SUBJECT DETECTION is on for people/animals/vehicles but there's none in the frame and the camera focuses on a chair, is the chair still considered a SUBJECT? This is important to fully undrstand cases below.

CASE 1 - "Detect Priority AE with AF" OFF + SUBJECT TO DETECT ON or OFF: metering considers whole area but is somewhat weighted more on POINT in focus (where POINT in focus may be a SUBJECT if SUBJECT DETECTION is on and either a person/animal/vehicle is detected).

CASE 2.1 - "Detect Priority AE with AF" ON+ SUBJECT TO DETECT OFF: metering is based on the entire screen, there is no somewhat weight on the POINT in focus. That's to say thea if "Detect Priority AE with AF" ON but the camera subject detection is off, the metering ignore the FOCUS point and considers the whole area.

CASE 2.2 - "Detect Priority AE with AF" + SUBJECT TO DETECT ON: metering is based on the point or AF area where the SUBJECT has been detected. QUESTION 2: if no person/animal/vehicle is being detected, does the camera still base metering on the POINT in focus?

Re: R5 Mk2 : detect Priority AE with AF

NatalyaP — Wed, 11 Sep 2024 00:14:35 GMT

Greetings thegios,

To answer your first question, the term "subject" refers to anything that the photographer is wanting to focus. It can be people, animals, vehicles but it would also apply to anything else like a chair, window frame, house exterior, an apple, etc.

If the subject is a chair, it is still considered a subject and the rules would apply to what John_Q provided in his comments. This would answer your second question as well, the camera would still meter based on what the camera focuses on within the focus point, even if it's a chair.

Re: R5 Mk2 : detect Priority AE with AF

thegios — Wed, 11 Sep 2024 05:33:00 GMT

Thanks a lot 🙂

Re: R5 Mk2 : detect Priority AE with AF

Shawndawg — Fri, 02 Jan 2026 16:26:00 GMT

Isn’t that the same as spot meatering?

Re: R5 Mk2 : detect Priority AE with AF

Waddizzle — Fri, 02 Jan 2026 17:12:46 GMT

“ Isn’t that the same as spot meatering??

No. But, the behavior is different on flagship camera bodies from what ai am about to describe.. Spot Metering is best used with Spot AF. Both settings only use the center AF point. The metering does not evaluate the entire scene, just a small center area.

However, there’s one subtle aspect that is easily overlooked in the above discussion. The OP keeps referring to the lens being focused, the Canon specialists keep referring to the AF point being in focus.

In other words, the AF point must be active for the metering to work as described. If the AF point is locked, then the lens is also locked in focus.

But the lens being locked in focus doesn’t necessarily mean the AF point is also sctivr and locked. This is something to be aware of when using BBF.

Re: R5 Mk2 : detect Priority AE with AF

thegios — Fri, 02 Jan 2026 18:16:34 GMT

I don't think there's ever been a proper answer to my question.

Re: R5 Mk2 : detect Priority AE with AF

Waddizzle — Fri, 02 Jan 2026 19:07:57 GMT

Allow me to speculate, as I don’t own R5m2. The basic descriptions Priority AE provided above sound pretty much like the standard evaluative metering mode. But there’s a subtle difference.

Of course, the camera can only focus on a single one AF point at a time to fire the shutter, even though there could be multiple points capable of locking focus from moment to moment. The camera only uses one when the shutter fires. Hold that thought.

Conventional Evaluative Metering biases the exposure to the active and locked AF point. More specifically, it uses a small area centered around the locked AF point. Spot Metering does the same thing, but with a smaller area.
Priority AE mode sounds similar, except it sounds like it uses a larger area. I suspect the larger area of being the subject that it has identified.

Again, my description of Priority AE is pure speculation based on connecting several dots inspired by what the Canon Product Experts described.

Re: R5 Mk2 : detect Priority AE with AF

thegios — Sat, 03 Jan 2026 11:21:14 GMT

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

Re: R5 Mk2 : detect Priority AE with AF

Waddizzle — Sat, 03 Jan 2026 13:20:59 GMT

“

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.

Re: R5 Mk2 : detect Priority AE with AF

thegios — Sat, 03 Jan 2026 18:42:41 GMT

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"

Re: R5 Mk2 : detect Priority AE with AF

Waddizzle — Sat, 03 Jan 2026 18:51:23 GMT

“ 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.

Re: R5 Mk2 : detect Priority AE with AF

thegios — Sat, 03 Jan 2026 18:59:16 GMT

Yes.