Exposure changing while shooting High Speed Continuous and Servo Focus with the R6

[kevinbarre]

I can shoot a static subject in static light using the High Speed Continuous drive mode on the R6, and the first two frames will be correctly exposed, but all subsequent frames will be overexposed. 

Trying to figure out if there is a setting to keep the exposure automatically locked. I have it set for Center-weighted Average metering, and I have "AE lock metering after focus" set to locked, but this doesn’t seem to actually keep it locked when using Servo focus. Also, it's odd that it always jumps up in exposure and will stay there as long as I hold down the shutter. 

I'm using Aperture priority and Auto ISO. For a static shot using High Speed Continuous drive mode and mechanical shutter, I get the following frame stats:

Frame 1: 1/320 F2.5 ISO 2500

Frame 2: 1/320 F2.5 ISO 2500

Frame 3: 1/250 F2.5 ISO 4000

Frame 4: 1/320 F2.5 ISO 5000

Frame 5 (and all subsequent frames): 1/320 F2.5 ISO 5000

I get it that it's an Auto ISO issue, but this does not occur if I set the focus to One Shot. It will hold the exact same exposure for as long as I hold the shutter. Wondering if there's a way to lock the exposure for as long as I have the shutter button held.

I'm not interested in using the AE Lock button to hold exposure as I shoot, even though this DOES fix the problem. I'm wondering if there is a menu setting that will accomplish the same thing for as long as I hold the shutter.

[kevinbarre]

It happens with all of my lenses and the adapter. Sigma 35 Art, Sigma 24-70 2.8 Art, 50 1.2 L, Canon 85 1.2 L II USM

[ksch14]

Ok, I have almost the exact same setup.  So frustrating.  I would receive the ERR 01 notification occasionally.  Not sure if that is related but I just took off the adaptor, cleaned all contact points on lens and adaptor and shot off about 100 frames perfectly. fingers crossed that was the problem.

[kevinbarre]

I never did solve the issue. I think I'm giving up on Canon, frankly. They don't seem to care a bit about their flawed new hot-shoe design, or allowing third-party lenses into their R-mount ecosystem, so screw them. I bought a Fujifilm X-T5 yesterday after reading glowing reviews. I happen to already have a full staple of compatible lenses, so the switch may end up being a no-brainer. 

[ksch14]

It is frustrating.  I was thinking it was a software issue also. Thank you for figuring out what was causing it so I can avoid that mode.