topic Re: Exposure Issue with 7D Mk II in EOS DSLR & Mirrorless Cameras

Exposure Issue with 7D Mk II

djdoornink — Tue, 10 Mar 2015 04:46:27 GMT

All 7D Mk II Owners,

I've got a new 7D Mk II and I've found an exposure shift between One Shot and AI Focus modes.
Here is an example of what I am seeing:
Camera is set to AV Mode, F4.0, ISO 800. I'm shooting the same consistently illuminated scene.
Shooting in One Shot mode the shutter speed is 1/400.
Shooting in AI Focus mode the shutter speed is 1/250.

It's almost a full stop difference. Has anyone else seen this behavior?

Thanks,
DJD

Re: Exposure Issue with 7D Mk II

RobertTheFat — Tue, 10 Mar 2015 12:42:16 GMT

Something like that could happen if you were using, say, evaluative metering in one case and center-weighted metering in the other. I don't think the two AF modes preserve separate settings of the metering mode, but you could get that effect with the user-defined settings (C1, C2, C3) on the mode dial. So if you do happen to be using the user-defined settings, check to see if that's the problem.

Re: Exposure Issue with 7D Mk II

cicopo — Tue, 10 Mar 2015 12:46:16 GMT

Having it set to Auto ISO could cause that too. What are all the settings showing & does the exposure look identical when compared to each other?

Re: Exposure Issue with 7D Mk II

djdoornink — Wed, 11 Mar 2015 02:59:35 GMT

I did somemore testing today and determined that the effect is more noticable if the scene has high contrast. If the metering mode is Evaluative then AI Servo shutter mode is biased brighter to bring up the dark areas more than it does in One Shot shutter mode.

The effect only seems to rely on these two settings and is quite reproducable. I even reset all settng on the camera and the results were the same.

It looks to me like the Evaluative metering mode works differently depending on if you are in One Shot or AI Servo.

I really would be interested if anyone else has seen this.

Thanks,

Doug

Re: Exposure Issue with 7D Mk II

RobertTheFat — Wed, 11 Mar 2015 11:52:04 GMT

@djdoornink wrote:
I did somemore testing today and determined that the effect is more noticable if the scene has high contrast. If the metering mode is Evaluative then AI Servo shutter mode is biased brighter to bring up the dark areas more than it does in One Shot shutter mode.

The effect only seems to rely on these two settings and is quite reproducable. I even reset all settng on the camera and the results were the same.

It looks to me like the Evaluative metering mode works differently depending on if you are in One Shot or AI Servo.

I really would be interested if anyone else has seen this.

Thanks,
Doug

Maybe the Auto Lighting Optimizer behaves differently in the two cases. Try disabling it and see if that cancels the effect you're observing. (It's probably on by default in most of the shooting modes.)

Re: Exposure Issue with 7D Mk II

djdoornink — Wed, 11 Mar 2015 18:48:52 GMT

Bob,

Thanks for the suggestion. It only happens in Evaluative metering mode so I'll look into the Auto Lighting Opimizer setting tonight when I have access to my camera.

Cheers,

Doug

Re: Exposure Issue with 7D Mk II

djdoornink — Thu, 12 Mar 2015 13:53:00 GMT

Bob,

I disabled Auto Lighting Optimizer and it made no difference. Have you got any more ideas? By the way, someone on another forum confirmed they saw the same behavior with their 7D2. They suggested that I report it as a FW bug to Canon.

Cheers,

Doug

Re: Exposure Issue with 7D Mk II

RobertTheFat — Thu, 12 Mar 2015 18:40:25 GMT

@djdoornink wrote:
Bob,
I disabled Auto Lighting Optimizer and it made no difference. Have you got any more ideas? By the way, someone on another forum confirmed they saw the same behavior with their 7D2. They suggested that I report it as a FW bug to Canon.

Cheers,
Doug

Nope, sorry. I don't have a 7D2 myself, so I was just guessing, based on what I found in my 5D3 manual. (Except for the sensor size, the two cameras appear to be very similar.)

If you figure out how to get Canon's attention in such matters, be sure to post what you learned.

Re: Exposure Issue with 7D Mk II

djdoornink — Fri, 13 Mar 2015 16:20:58 GMT

I found this information for contacting Canon USA:

They're ready to help 24/7 via Email at http://bit.ly/EmailCanon or by phone at 1-800-OK-CANON (1-800-652-2666) weekdays between 10 AM and 10 PM ET (7 AM to 7 PM PT).

I haven't contacted them yet about this but I will this weekend and see if anything comes of it.

Cheers,

Doug

Re: Exposure Issue with 7D Mk II

djdoornink — Mon, 16 Mar 2015 19:08:35 GMT

I filed an issue with Canon USA but I haven't gotten a reply yet. I did one more interesting test though. I tried this same scenario on my original 7D and it behave the same way. So maybe this is a tuning to the Evaluative exposure mode that is in multiple cameras.

I would be interested in having someone with a 5D MK III try this test and report how it behaves in a similar situation.

Thanks,

Doug

Re: Exposure Issue with 7D Mk II

TTMartin — Wed, 25 Mar 2015 22:05:06 GMT

@djdoornink wrote:
I did somemore testing today and determined that the effect is more noticable if the scene has high contrast. If the metering mode is Evaluative then AI Servo shutter mode is biased brighter to bring up the dark areas more than it does in One Shot shutter mode.

The effect only seems to rely on these two settings and is quite reproducable. I even reset all settng on the camera and the results were the same.

It looks to me like the Evaluative metering mode works differently depending on if you are in One Shot or AI Servo.

I really would be interested if anyone else has seen this.

Thanks,
Doug

Evaluative metering is weighted to the active AF point. Where you using the same AF point in both cases?

edit: Also the iFCL metering in the classic 7D uses information from multiple autofocus points. It knows which AF points have achieved focus, and which ones have nearly achieved focus, and weights the exposure reading towards the zones those AF points are in on the basis they are likely to be covering the subject. I assume the 7D Mk II's RGB metering is similar.