R1 firmware suggestion: link spot metering to active AF point

[Cyrano]

I shoot dance performances, which often have extremely challenging lighting, such as:

• One dancer is in a bright spotlight, while other dancers are in near-shadow. 
• Lighting changes bright-dark-bright every second. 
• Dancers wear black leotards on a dimly-lit stage, with only their faces not in shadow.

I must use Manual exposure mode in such circumstances, as no other mode can reliably avoid overexposing the dancers' faces. Even this solution fails when the lighting changes faster than I can adjust exposure. 

My life would be much improved if I were able to link spot metering (and maybe also center-weighted metering) to the active AF point. 

I was surprised that this feature wasn't included at launch. Even my 10-year-old 1DX body has a custom function for AF-point-linked spot metering. 

[Waddizzle]

Like a 1D series DSLR, I would expect a 1 Series MILC body like the R1 to have Spot Metering linked to an active and locked Spot AF point.  If the Spot AF point was both active and locked, then the camera can display it during image playback.  So can Canon DPP4.

If the conditions are not met, then the camera will probably default to metering from the center AF point. If you use BBF, then keep this in mind.  

I don’t know how linking Spot Metering to using Spot AF with subject detection and eye tracking would work.  Or even if it should work. 

I don’t foresee Center Weighted Metering to change its behavior.  If it did so, then that would be an entirely new metering mode that would need a new name. 

[Cyrano]

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@Waddizzle wrote:

I don’t know how linking Spot Metering to using Spot AF with subject detection and eye tracking would work.  Or even if it should work. 

I use Servo AF to track a single dancer's movement across the stage. Regardless of how the active AF point was set (e.g., subject detection, eye control, whole-field auto AF), half-pressing the shutter button causes the active AF point to track the dancer. I'd like spot metering applied continuously to the active AF point as that point moves around the frame, just as autofocus is continuously applied. 

I don’t foresee Center Weighted Metering to change its behavior.  If it did so, then that would be an entirely new metering mode that would need a new name. 

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Indeed. It would be AF-Weighted Metering ... hey, wait a minute ... I think I need to check the Advanced User Guide again ...

Bingo! Page 332 describes "AE for Priority Subjects during AF."  With the camera set to Evaluative metering and "Subject to Detect" set to anything other than "None",

• Enabling this function causes metering to be based on the AF point/area where the subject was detected. 
• Disabling this function causes the entire screen to be metered. 

I just did a very quick test of this feature, using subject detection set to People, Av mode, and Evaluative metering:

• The subject was in the center of the frame. The area to the left of her was more darkly lit, and the area to the right of her was more brightly lit.
• I allowed the camera to detect the subject's face, then locked AF via shutter button half-press. 
• I then panned left-to-right as far as possible while maintaining the AF lock on the subject.
• While panning, I observed the changes in shutter speed resulting from the changes in illumination.
• With the feature Disabled, panning resulted in a shutter speed variation range of 2 stops.
• With the feature Enabled, panning resulted in a shutter speed variation range of 0.5 stops.

I'm eager to try this feature out in my next theatrical shoot. I'm hopeful it will be sufficiently effective to eliminate the need for AF-linked spot metering. 

[Waddizzle]

Evaluative Metering has always behaved that way in all Canon bodies that offer it. While it does prioritize metering to an AF point, there are a couple of caveats. 

I have already mentioned the fact that the AF system must be active and an AF point must be locked.  Using Servo and Eye/Subject tracking should meet that requirement. 

The second one is Evaluative Metering does analyze the entire frame. I heard someone on YouTube say the sensor is capable of adjusting the gain for darker or brighter areas to keep them from being over/under exposed.