Exposure Issue with 7D Mk II

[DJD]

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

 

[Rahul]

I've never seen this on my 7D2, but then maybe I haven't been looking out for anything like this.

I will test this later today and revert.

 

[DJD]

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 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 whether you are in One Shot or AI Servo.

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

Thanks,
Doug

 

[StudentOfLight]

Out of curiosity, if the scene is consistently illuminated then why not shoot in manual exposure mode?

 

[StudentOfLight]

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

What metering mode are you using?
Can you please share the two images where you are seeing the variance in metering?

 

[monkey44]

I no longer shoot in the AI Servo mode much (more one-shot lately) -- but the other day caught a 'territory battle' between two lizards (quite a unique opportunity) and was coincidentally in Servo and Evaluative with single CP surround, and experienced 'some exposure oddness' in the captures when opened in the PC...

I did not attribute it to a shift, but will go back and see if I can figure it out ... but with AI servo and the AF active, it would seem the camera might do exactly that kind of change as a response to light changes -- which in the lizard case, was very true ... very bright sunshine and the lizards spilled over into shade a few times.

BTW: It was a really neat experience, and I was totally unprepared for it. Was walking a boardwalk in a nature preserve with the 7D2 and 100-400 v2 set for distance and birds in flight. Suddenly, these two male lizards started a territory fight about three feet away on the top railing -- and here I was without my normal set-up of two cameras -- one long, one short... Bummer, and it happeneed so fast, I had no time to change from what I had, so just started pulling the trigger. Got some decent shots, but over-exposed because it was a 100-400 on a 7D2 and only three feet away. AND, I was set for BiF ... fast exposure and high ISO and EC up a third -- BLAH !!! ... Was able to pull out some really cool shots from the RAW side tho ... in a situation we don't often get a chance to shoot. A lizard wrestling match -- awesome ...

Anyway, I noticed tho that under that situation, something odd happened to the light, but didn't pay a lot of attention to it as under those conditions, I was not surprised to have unusual images ...

 

[ksgal]

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

I believe I can confirm it.. when the AF point is on a highlight. In my case I'm putting the AF point on one of the lights in the ceiling and then rotated thru Single shot, AI Focus and AI servo and one of these is definitely not like the others. In my case one shot is definitely darker. Shutter went from 1/200 to 1/400 in single shot.

However when placed on a more midtone af point (same scene) there was no difference-went same shutter on all three (single shot/ai servo/ai focus)


Anyone else?

 

[DJD]

I believe I can confirm it.. when the AF point is on a highlight. In my case I'm putting the AF point on one of the lights in the ceiling and then rotated thru Single shot, AI Focus and AI servo and one of these is definitely not like the others. In my case one shot is definitely darker. Shutter went from 1/200 to 1/400 in single shot.

However when placed on a more midtone af point (same scene) there was no difference-went same shutter on all three (single shot/ai servo/ai focus)


Anyone else?

ksgal,

Thanks for confirming this. Your experience is similar to how I discovered the behavior myself, focusing on a brightly illuminated object with a relatively dark background. And my results were also pretty much the same as yours, shutter speed went from 1/250 in AI Focus to 1/400 in Single Shot.

Your confirmation makes me feel better since I was trying to decide if there was something wrong with my camera and I needed to send it back for a replacement. It's still an unexpected Auto Exposure behavior that doesn't seem right to me. But, from my testing, it only occurs in Evaluative metering and I can live with it for now.

But I'd still like Canon to say why it behaves that way...

Cheers,
DJD

 

[DJD]

What metering mode are you using?
Can you please share the two images where you are seeing the variance in metering?

I was using Evaluative metering mode. I don't have access to my pictures right now but I can say that it was a brightly illuminated object with a relatively dark background. In other words, a high contrast scene and focusing on a light area.

Cheers,
DJD

 

[ksgal]

I'm thinking you found a firmware bug DJD - JMHO. I don't use AV very often, I tend to go manual but I sure will keep this in mind if I'm needing to use AV. I guess as long as you don't focus on a highlight, you are ok, but it does throw a monkey wrench into things - have to remember to use AI focus. I still say you send a note to Canon, or we post on a couple other forums so hopefully this gets noticed and fixed in a firmware update.

I don't plan on worrying about it - I can fix a stop difference since I shoot raw all the time anyways. But I suspect this is only one of several bugs in the current firmware.

 

[DJD]

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 behaves 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