5d Mark III - Metering Underexposed

[rjs1981]

So first off, I apologize as I think I've seen a similar thread here but I can't find it anymore!

I purchased a 5d Mark III as an upgrade from my 7d a couple of weeks ago and, although I am happy, there is one main issue that is bothering me.

When I meter a "perfect" exposure, the camera is delivering about a full stop UNDER that.

My normal settings are; 

Shoot in M

Center focus point

Spot metering

AI Servo.

I generally shoot 2/3 over anyway, and find that I'm needing to now shoot at least 1 2/3 over to get the same result as my 7d. In addition to that, I'm getting a noticeable vignette in lower (but even/consistent) light situations.

I have tried all the different metering options, including variations on the focus points. I have done a full factory reset and the issue is consistent across all my lenses. 

Any ideas?

[RobertTheFat]

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@cale_kat wrote:

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@Hannahgivas wrote:
"Overview page on the 7D... iFCL Metering with 63-zone dual-layer metering system uses both focus and color information to provide accurate exposure even in difficult lighting" I believe the 5d mkiii has the 63 zone, not the 7D :), off the topic of the 7D, the 5D mkiii is my problem, and I am having a heck of a time with metering with it! and using the selected AF point is absolutely useless! 😞

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Good stuff here, http://cpn.canon-europe.com/content/education/infobank/exposure_settings/iFCL_metering.do, including a picture of the 63-zone 7D metering sensor. LOL (I said I'd clipped it off Canon's web site.)

Camera has to meter through something. What lenses are you using?

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What isn't explained in that reference is how the 7D and the 60D map their 63-zone metering system onto a sensor with only 19 and 9 autofocus points, respectively. Incidentally, the URL you provided includes a trailing comma that must be removed in order to allow the link to be followed.

[TCampbell]

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@RobertTheFat wrote:

What isn't explained in that reference is how the 7D and the 60D map their 63-zone metering system onto a sensor with only 19 and 9 autofocus points, respectively. Incidentally, the URL you provided includes a trailing comma that must be removed in order to allow the link to be followed.

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The AF sensors are located on the floor of the mirror body (just below the reflex mirror).  The metering sensors are up in the viewfinder above (also, this is why we are cautioned to cover the viewfinder to get more accurate metering if our eye isn't blocking the viewfinder from stray light.)

Here's a diagram that may help (note: this is from a 30D):  http://www.imaging-resource.com/PRODS/D30/D30A3.HTM

[RobertTheFat]

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@TCampbell wrote:

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@RobertTheFat wrote:

What isn't explained in that reference is how the 7D and the 60D map their 63-zone metering system onto a sensor with only 19 and 9 autofocus points, respectively. Incidentally, the URL you provided includes a trailing comma that must be removed in order to allow the link to be followed.

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The AF sensors are located on the floor of the mirror body (just below the reflex mirror).  The metering sensors are up in the viewfinder above (also, this is why we are cautioned to cover the viewfinder to get more accurate metering if our eye isn't blocking the viewfinder from stray light.)

Here's a diagram that may help (note: this is from a 30D):  http://www.imaging-resource.com/PRODS/D30/D30A3.HTM

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Canon's overview, cited by cale_kat in a reference to their Web site, seems to say that in each of the 63 metering zones one of the autofocus points contributes to the analysis of the exposure required. It's straightforward to see how that might work on a 5D3, which has 63 autofocus points. It's less obvious how they'd handle it on a 7D or a 60D, both of which have far fewer than 63 autofocus points. A diagram of a 30D isn't likely to clarify the point, inasmuch as the 63-zone metering system didn't exist on the 30D.

[TCampbell]

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@RobertTheFat wrote:

Canon's overview, cited by cale_kat in a reference to their Web site, seems to say that in each of the 63 metering zones one of the autofocus points contributes to the analysis of the exposure required. It's straightforward to see how that might work on a 5D3, which has 63 autofocus points. It's less obvious how they'd handle it on a 7D or a 60D, both of which have far fewer than 63 autofocus points. A diagram of a 30D isn't likely to clarify the point, inasmuch as the 63-zone metering system didn't exist on the 30D.

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They only need a metering point which is close.  No need for a one-to-one mapping.

Even on the 5D III where there's a 61 point AF system and a 63 zone metering system, the AF points don't map directly to metering points.  

See:   http://cpn.canon-europe.com/content/education/technical/inside_canon_eos_5d_mark_iii.do  

On this page, expand the "Metering & Exposure Control" section to view the diagram.

The entire top and bottom row of metering points have no AF points in them at all.

[ebiggs1]

"They only need a metering point which is close.  No need for a one-to-one mapping."

Exactly.  The point I was trying, poorly, to make.

[Hannahgivas]

So my question is how do I master the metering on 5d mkiii, I'm having a heck of a time, trying all modes, trying metering off of center point, set exposure and recompose scene, but still having issues

[cb7]

Im having the same under exposure issues with my 5d mk3. Have you or anyone else found any solid answers yet?

[ricardo474]

I also just purchased a 5D lll and put away the 7D, which did a terrible focus job. But...it did a far better job of metering. I have heard alot of technical talk about the cameras etc..but the FACT remains that the 5D lll does not produce the metering desired. I have used the 24-70 2.8 L  70-2002.8 LIS and the 400 L and the camera normally produces underexposed results. Don't start with all this comparison stuff...It underexposes a significant amount of the time. If Canon has an answer let them give a solution, but don't argue with the people who have used other digitals for thousands of frames and talk about comparing to other cameras. So... yes I join hands with those that are experiencing this underexposure problem with the 5D lll and await an answer from CANON.....

[Waddizzle]

Don't wait for an answer from Canon on these forums.  Contact them directly at Customer Support, 1-800-OK-CANON.

I think the metering mode, and the subject matter may have a lot to do with it.  I have frequently taken entire series of shots, only to later discover that, according to the histogram, were underexposed by nearly 1 EV on average. 

It doesn't seem to matter which camera I use, either.  On one occasion when I was trying to take a shot with a lot of dynamic range, I mounted the camera on a tripod and took different shots with different exposure modes.  I suggest that you try it before you call Canon.  Try taking the same shot, but with different exposure modes.  I tried them all, and discovered that they do what they say that they do.

[RobertTheFat]

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@ricardo474 wrote:

I also just purchased a 5D lll and put away the 7D, which did a terrible focus job. But...it did a far better job of metering. I have heard alot of technical talk about the cameras etc..but the FACT remains that the 5D lll does not produce the metering desired. I have used the 24-70 2.8 L  70-2002.8 LIS and the 400 L and the camera normally produces underexposed results. Don't start with all this comparison stuff...It underexposes a significant amount of the time. If Canon has an answer let them give a solution, but don't argue with the people who have used other digitals for thousands of frames and talk about comparing to other cameras. So... yes I join hands with those that are experiencing this underexposure problem with the 5D lll and await an answer from CANON.....

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The convenient thing about that attitude is that it's a lot less work than actually trying to analyze what, if anything, you're doing wrong. I have a 5D3 and two 7D's, and I've probably taken as many thousands of frames as you have. And my last camera that consistently and unexplainably underexposed was a Rebel XTi. (My wife also had one, and it didn't; so there may actually have ben a hardware problem.) But by all means have it your way. We'll stop bothering you with "all this comparison stuff", and you can feel free to wait as long as necessary for Canon to fix your problem.