# Canon 6D Under-Exposing?



## Area256 (Dec 5, 2012)

This article suggests that the Canon 6D images are darker by about 1-2 stops vs. other Canon and Nikon cameras with identical settings (at least with long exposures).

http://www.borrowlenses.com/blog/2012/12/is-the-canon-6d-under-exposing/

I'm skeptical about this, and currently the article did the tests only with jpegs - so it's entirely possible this just has something to do with the jpeg engine or jpeg settings. 

However, I was wondering if anyone who owns a 6D has seen this issue? or can confirm this issue does/doesn't actually exist in the RAW files?


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## x-vision (Dec 5, 2012)

These shots confirm what I've noticed with other 6D test shots: that the 6D has a tendency to 'expose to the left'.
Reminds of my 40D, which does the exact same thing.

Not sure why Canon decided to implement the 6D exposure like that but I can tell for sure that this was their intent.
Overall, nothing to worry about. This is not a 'bug' but a feature .


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## Tozz (Dec 5, 2012)

So why is the difference between this 2 shots not that big??
http://img1.focus-numerique.com/focus/articles/1566/canon-6d-100iso-nrstan-big.jpg
http://img1.focus-numerique.com/focus/articles/1541/nikon-d600-100iso-nrstan-big.jpg

Both
ISO100, f/5.6, 1/4s


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## Liverastic (Dec 5, 2012)

Well, as somebody in the comments section of that page mentioned, if its underexposing, a long exposure (like the 30 seconds in the night shot of San Francisco on the link) will exacerbate the issue.

The test shots on those links were shot at 1/4 sec.

I am pretty concerned about this issue, I'm really hoping it's just the factory settings, like Auto Lighting Optimizer being turned on.

My T2i overexposes constantly, especially with my 28-135mm. I'd really like to be able to use aperture priority mode without having to mess with the EV settings constantly.


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## DanielW (Dec 5, 2012)

Liverastic said:


> Well, as somebody in the comments section of that page mentioned, if its underexposing, a long exposure (like the 30 seconds in the night shot of San Francisco on the link) will exacerbate the issue.
> 
> The test shots on those links were shot at 1/4 sec.
> 
> ...


I oftentimes shoot with my 60D overexposing by 0.3 stops (sometimes 0.6), and it has never annoyed me. I just set it to +0.3 and leave it like that.


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## Liverastic (Dec 5, 2012)

DanielW said:


> Liverastic said:
> 
> 
> > Well, as somebody in the comments section of that page mentioned, if its underexposing, a long exposure (like the 30 seconds in the night shot of San Francisco on the link) will exacerbate the issue.
> ...



Are you looking for a brighter look, or does +0.3 look more correct? I'm constantly moving between -.6 and -1.3 just so images aren't totally washed out and clipping.

Sorry if this is derailing the thread a bit. It seems like this could have a major impact on night sky/star field shooting, which I am looking forward to doing when I go full frame.


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## Area256 (Dec 5, 2012)

Tozz said:


> So why is the difference between this 2 shots not that big??
> http://img1.focus-numerique.com/focus/articles/1566/canon-6d-100iso-nrstan-big.jpg
> http://img1.focus-numerique.com/focus/articles/1541/nikon-d600-100iso-nrstan-big.jpg
> 
> ...



I'm guessing the Nikon is about 1/3 of a stop brighter here, but it's not a big deal, and it could just be caused by the transmittance of the lenses used - or any number of jpeg engine differences. So for normal applications, I'd guess we won't see a meaningful difference.

However, I'm a little worried about long exposures. Interestingly Canon seems to recommend ISO 400 for bulb exposures... I wounder if this is the reason for that?


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## BruinBear (Dec 5, 2012)

Tozz said:


> So why is the difference between this 2 shots not that big??
> http://img1.focus-numerique.com/focus/articles/1566/canon-6d-100iso-nrstan-big.jpg
> http://img1.focus-numerique.com/focus/articles/1541/nikon-d600-100iso-nrstan-big.jpg
> 
> ...



Could be differences in the lenses. Do you know what lenses were used for this test? D600 looks sharper but could just be the lens.


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## DanielW (Dec 5, 2012)

Liverastic said:


> DanielW said:
> 
> 
> > Liverastic said:
> ...


I see no problem at all in derailing...
I've found myself quite often disagreeing with the camera's meter and increasing exposure in LR, and (although those with better knowledge on the subject may disagree) digital sensors deal better with overexposure than the opposite. I always shoot RAW, so I can bring exposure down if necessary with no loss of detail; on the other hand, I would probably introduce noise if I were to bring exposure back up.
It might sound like it's all good, but I've screwed up a few (too many) shots already by doing like that. When shooting something important, I always overshoot and vary exposure. 
I think it's about knowing your camera, too, and having it do what you want and adapt it to your own photographic tastes/needs.
Neuro and others here sure know it in details; I just read it in one of the first books I bought (read quote below) and believed... 

"The camera’s sensor does not give equal weight to all tones. In fact, your digital sensor is heavily weighted to the brightest areas in your photo. (...) Taken another way, the camera has a ﬁxed number of numeric values for describing the brightness of a pixel. Fifty percent of those numeric values are devoted to the brightest f-stop in your photo. Each successively darker f-stop receives one-half the number of the f-stop ahead of it, until the shadows receive only a small sliver of the total possible values. This is important information, because all detail in your photos is a result of subtle differences in tone and color between adjacent pixels. In the shadows, where fewer values are available to describe these differences, it becomes more difficult to retain details. Underexposing photos drives more of the information contained within a photo deeper into the shadows, causing a loss of detail and an increase in noise (unwanted color impurities) in the photo."
(Taken from _Perfect Digital Photography, 2nd edition_, hopefully not infringing any copyrights.)

Hope it helps.


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## Marsu42 (Dec 5, 2012)

x-vision said:


> Not sure why Canon decided to implement the 6D exposure like that but I can tell for sure that this was their intent. Overall, nothing to worry about. This is not a 'bug' but a feature .



Indeed (if this is really the case) - on a consumer-oriented camera exposing to the left is the safe bet against blown highlights, esp. on a dr-limited sensor like Canon. People who shoot sooc jpegs and don't do much postprocessing probably will never notice the lower shadow resolution (esp. against ettr). 

But no one stops you from using +1/3 ev exposure compensation all the time


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## Artifex (Dec 5, 2012)

BruinBear said:


> Tozz said:
> 
> 
> > So why is the difference between this 2 shots not that big??
> ...



I might be wrong, but I also think this could result as much of a lens difference than a camera difference. Even if both photo where taken at f/5.6, different lens have different light transmission for the same aperture; the light transmission is calculated by T-stop values, the F-stop values taking only in account the focal length divided by the diameter of the entrance pupil. There is normally not that much difference in light transmission between lens at the same aperture, but it could still be a factor.


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## ThuiQuaDayNe (Dec 5, 2012)

DanielW said:


> Liverastic said:
> 
> 
> > Well, as somebody in the comments section of that page mentioned, if its underexposing, a long exposure (like the 30 seconds in the night shot of San Francisco on the link) will exacerbate the issue.
> ...


I did the same with my 60D.. +.3 or +.5


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## Area256 (Dec 5, 2012)

DanielW said:


> "The camera’s sensor does not give equal weight to all tones. In fact, your digital sensor is heavily weighted to the brightest areas in your photo. (...) Taken another way, the camera has a ﬁxed number of numeric values for describing the brightness of a pixel. Fifty percent of those numeric values are devoted to the brightest f-stop in your photo. Each successively darker f-stop receives one-half the number of the f-stop ahead of it, until the shadows receive only a small sliver of the total possible values. This is important information, because all detail in your photos is a result of subtle differences in tone and color between adjacent pixels. In the shadows, where fewer values are available to describe these differences, it becomes more difficult to retain details. Underexposing photos drives more of the information contained within a photo deeper into the shadows, causing a loss of detail and an increase in noise (unwanted color impurities) in the photo."
> (Taken from _Perfect Digital Photography, 2nd edition_, hopefully not infringing any copyrights.)



That is correct. If you want to know the reason is quite simple. Humans see light in an approximately logarithmic fashion (as if we were taking the log (base ~2) of the actual light we see). (We also hear in a logarithmic fashion as well.) This is very useful to us since it means we can see when there are just a few photons, and when there are tens of thousands of times more photons per until area of our eyes - and yet it looks to us like it's only a few times brighter.

Sensors are linear, they just measure the approximate number of photons per pixel. So if your images has 9 stops of dynamic range, the brightest stop has half the the available data. And the darkest stop only has ~0.2-0.4% of the data.

Exposing to the right (as long as you aren't blowing out the highlights), is a very good idea if you want to have more freedom to play with your images afterwards - since you'll have much more data in the shadows. Just one stop of "overexposing" will give you twice the shadow detail.

However I digress, and still want to know what's going on with those 6D long exposures...


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## DanielW (Dec 5, 2012)

Area256 said:


> DanielW said:
> 
> 
> > "The camera’s sensor does not give equal weight to all tones. In fact, your digital sensor is heavily weighted to the brightest areas in your photo. (...) Taken another way, the camera has a ﬁxed number of numeric values for describing the brightness of a pixel. Fifty percent of those numeric values are devoted to the brightest f-stop in your photo. Each successively darker f-stop receives one-half the number of the f-stop ahead of it, until the shadows receive only a small sliver of the total possible values. This is important information, because all detail in your photos is a result of subtle differences in tone and color between adjacent pixels. In the shadows, where fewer values are available to describe these differences, it becomes more difficult to retain details. Underexposing photos drives more of the information contained within a photo deeper into the shadows, causing a loss of detail and an increase in noise (unwanted color impurities) in the photo."
> ...


Thanks for the explanation!
Are you familiar with some book or website where I can read more about it? I do enjoy digressions...


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## Martin (Dec 6, 2012)

The most funny and strange thing is that all Canons expose incorrectly and the most dissapointing thing is that almost no one in Canon would like to correct this (especially if we have to deal with banding when pushing up shadows) Some more advanced users noticed that especially when they has switched from Nikon or use any external light meter. To be honest it even does not require such a comparison. Just shoot any white wall or homogeneous surface. The histogram peak should be in the center. In canon bodies it is not. I've checked it with a lot of bodies and it always expose incorrectly. You even don't heve to mesure it-when you shoot any other brands-canons are darker. That's a huge mistake when you post process and its even more stupid if you shot jpgs. I have no idea why people or other testing sites do not mention it loudly because it is serious and last for years. Take Nikon, take sekonic-identical metering, take Canon ca. -1/2 underexposure or even up to -1EV. As mentioned before I don't really get it, as Canon should have even a tendency to overexpose, cause there is a problem with banding when pp an underexposed image. Really strange for me...especially when we talk about a such a photo company.


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## ThuiQuaDayNe (Dec 6, 2012)

Mikael Risedal said:


> Area256 said:
> 
> 
> > This article suggests that the Canon 6D images are darker by about 1-2 stops vs. other Canon and Nikon cameras with identical settings (at least with long exposures).
> ...



I see.. very interesting. So should we prefer a camera with higher sensitivity for a given lumen?


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## Martin (Dec 6, 2012)

...and to be honest I have no idea why someone mentioned the underexposing problem only with 6d while it is and was present in 5d2 and 5d3 as well. Maybe 6d underexposes even much more.


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## Martin (Dec 6, 2012)

Also, I think that taking into consideration canon ISO sensitivities and explaining the underexposure in that way is completely illogical. OK..let it be that Canon cheat a little beat for marketing and put even ie. ISO 200 for 100, BUT the exposure should be always correct providing well lit images (well means-in line with standards, so the user may correct it with the scene evaluation, but the basic exposure must be predictable and" correct"). Maybe there is ie. iso 200 instead for 160 however, the light meter should match a longer shutter speed to give a standard lit image. Otherwise any user will have to deal with it in PP. That is not a standard behaviour. Canon could even name 3200 for ISO 200 (to make a wow! factor for high sensitivities) but it should not give you completely black image.


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## Martin (Dec 6, 2012)

trolling? I am writing about the facts only.


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## PVS (Dec 6, 2012)

Martin said:


> ...and to be honest I have no idea why someone mentioned the underexposing problem only with 6d while it is and was present in 5d2 and 5d3 as well. Maybe 6d underexposes even much more.



Funny you say that because in this side by side comparison a completely different conclusion is found:
http://nevillelockhart.wordpress.com/2012/11/20/nikon-d800-vs-canon-mkiii-part-1/


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## rpt (Dec 6, 2012)

Tozz said:


> So why is the difference between this 2 shots not that big??
> http://img1.focus-numerique.com/focus/articles/1566/canon-6d-100iso-nrstan-big.jpg
> http://img1.focus-numerique.com/focus/articles/1541/nikon-d600-100iso-nrstan-big.jpg
> 
> ...


To me the Nikon pic looks a bit washed out or OOF or something. The Canon one looks crisp. May be slightly more black in it but crisp.


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## ThuiQuaDayNe (Dec 6, 2012)

rpt said:


> Tozz said:
> 
> 
> > So why is the difference between this 2 shots not that big??
> ...



Agreed.. the Nikon looks a little washed out compared to the 6D.. probably due to less contrast. But the 6D underexposed compared to D600 in this picture. If you look at the bottom of the images at the camera or the shadow around the front of the car. There is virtually no shadow between the car and book (brighter) and the camera black accordion area is more pronounced on the D600. Either the Nikon overexposed or the Canon is underexposed or perhaps DR?


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## CharlieB (Dec 6, 2012)

Not that the 6D is on equal footing as the old 400D, or 350D... 

But both of those cameras had some exposure "issues" as delivered.

I just sent mine in for adjustment, which they did at no charge (on my old 400d).

I just said - turn it up a half stop. It came back turned up a half stop. 

:-\


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## Area256 (Dec 6, 2012)

Ok, the author of the original article is getting some strange results (and we may actually get to blame this on Nikon - I'm not a fan boy, but hey this is CR  ). 

I'll quote the interesting part here:



> The images you’re looking at seem to indicate the converse – that it’s the D600 that’s overexposing. I suspected this might be the case, which is why I’ve posed this entire piece as a question and an ongoing series of discoveries.


Source: http://www.borrowlenses.com/blog/2012/12/is-the-canon-6d-under-exposing/ (Post Update)

It looks like the D600 may be unusually sensitive (comparied to the D800, 5D2/3, and 6D). I'm still blaming the jpeg engines (likely Nikon's d600 engine) for this strangeness however. Have to wait until he posts some RAW images, or someone else does this test to be sure though.

The lens he is using could also be an issue, but generally the T-stop difference shouldn't be much between similar lenses.


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## hemidesign (Dec 6, 2012)

IMO, this website (borrowlenses) its all BS...


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## Martin (Dec 6, 2012)

PVS said:


> Martin said:
> 
> 
> > ...and to be honest I have no idea why someone mentioned the underexposing problem only with 6d while it is and was present in 5d2 and 5d3 as well. Maybe 6d underexposes even much more.
> ...



Strange thing, however they should use an external meter as reference no a camera's one. I sell my 5d2 but I think it underexposed in similar way that 5d3 (-1/3 - 2/3)...I did not have D800 but it should work like other Nikons. However the test you've posted shows ineed a the different conclusion. 

Please make a simple test-take few Nikon DSRLs, Canon, and ie. Sekonic Lightmeter-check the metering on ie. white wall-the histograms will be completely different in terms of exposure (histogram peak). I checked it some time ago with 2x5d2, 5d3, d70, d90, d300, d700 and sekonic. When I switched to Canon and just thought that my camera's meter was broken, cause I was used to brighter images in standard exposure. Nikon/Sekonic were ideantical giving a histgoram peak in center. Canon's peak were biased to the left ( ca. -2/3 or -0,5 EV).

A also found that there are some lens which gives a perfect exposure for my bodies - 85mm 1.8. The histogram peak was perfectly in center. All my other lenses gives different results. Why? No idea, aperture maybe ?


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## PVS (Dec 6, 2012)

If you take a look at the updated link in the OP you'd see it was the D600 which overexposed in studio shots compared to D800, 5Dmk2, 5Dmk3 and 6D.


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## skitron (Dec 9, 2012)

FWIW, I found the 6D to underexpose a significant amount compared to 5D2 and 50D. That was part of the reason it got sent back in favor of a 5D3. Of course jmo, ymmv, etc...


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## justsomedude (Aug 14, 2013)

skitron said:


> FWIW, I found the 6D to underexpose a significant amount compared to 5D2 and 50D. That was part of the reason it got sent back in favor of a 5D3. Of course jmo, ymmv, etc...



I know this is an old thread, but...

I just ran my 6D through the paces this past weekend on a few event gigs, and found (with identical settings to my 5D3) that it indeed underexposes... by quite a bit! To get things in line, I had to run my exposure compensation between +1 and +1.6 EV. This gave me results that were consistent with my 5D3.

Is there any update on this from Canon? Firmware update, etc.?

I find it curious that this is appearing to be a repeatable issue out there amongst 6D users.


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## Wildfire (Aug 14, 2013)

They've updated this article. It was actually a problem with the Nikon D600 over-exposing (aperture issue, nothing to do with JPEG), and the Canon was fine.

I own a 6D and have had no problems with exposure. Since I prefer the 'expose to the right' method I find that pretty much any digital camera exposes a little darker than I would like, and I set exposure compensation accordingly.


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## Marsu42 (Aug 14, 2013)

justsomedude said:


> To get things in line, I had to run my exposure compensation between +1 and +1.6 EV. This gave me results that were consistent with my 5D3.



If a slight underexposure should be the case: the 6d is also marketed for travel/tourism which implies a lot of jpeg/daylight use, so protecting people from blown highlights seems reasonable while people using the "pro" 5d3 are probably expected to know what they're doing and shoot raw so you can recover the highlights.


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## m6d4 (Aug 15, 2013)

I experienced this problem as well but then I had sigma35mm1.4 new lens and I thought the problem is with the lens not the camera.
=Deep


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## bereninga (Aug 15, 2013)

I noticed this on my 6D as well. I have to constantly set the exposure compensation and it is pretty annoying to keep doing that.


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## sandymandy (Aug 15, 2013)

I think it gotta do with the lens. Using my m42 lenses in AV mode sometimes the exposure is just...so off.
Never had any problems with the newer EF lenses


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## GMCPhotographics (Aug 15, 2013)

Martin said:


> ...and to be honest I have no idea why someone mentioned the underexposing problem only with 6d while it is and was present in 5d2 and 5d3 as well. Maybe 6d underexposes even much more.



The Canon metering system has always been slightly over sensitive to bright highlights. Fair comparisons to metering can only be made with grey test scenes and controlled lighting. But the metering isn't always linear or compatible to other camera systems. I've found my 5DIII's to be the most stable of metering on a Canon system yet, My 5DII cameras had a similar metering system to the older 5D cameras, but rendered images which were slightly brighter due to the higher 14bit output of the 5DII. 
I tend to use fast primes so my iso values are generally quite low. I like my images to have a slim DOF and low noise.


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## CTJohn (Aug 15, 2013)

I'm so glad to read this string. I've experienced what I thought was underexposure with my 6D as well....never had the problem with my 7D. 

Is anyone have a white balance problem with interior shots? Even when I set the white balance to tungsten on some shots, they come out yellow/orange-ish. Exterior shots seem to be fine.


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## thgmuffin (Aug 15, 2013)

CTJohn said:


> I'm so glad to read this string. I've experienced what I thought was underexposure with my 6D as well....never had the problem with my 7D.
> 
> Is anyone have a white balance problem with interior shots? Even when I set the white balance to tungsten on some shots, they come out yellow/orange-ish. Exterior shots seem to be fine.



It does seem to underexpose just a little bit for me. Unlike my T2i...

My interior shots end up yellow/orange-ish too. 

I guess exposure comp +1/3 is the way to go.


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## Aglet (Aug 15, 2013)

I've found various bodies to expose with various levels of error, no real surprise.

What I find more annoying tho, is an _inconsistent_ error on any given body.

E.G.
new Pentax K52s with fast zoom and sunlight.
- matrix metering is within 1/3 of Sekonic
- CWA and Spot on the same uniform surface are -1EV from matrix

I thot this may be due to the effect of lens corner shading in matrix EXCEPT that if I move to an indoor location, again on a smooth surface evenly lit by natural outside light thru windows, all metering modes are now the same result!

FWIW, my K52s underexposes considerably and inconsistently when outdoors in sunlight, no matter what metering mode I use and even sunny-16 numbers do not provide proper results but are often nearly 2 stops under... I need to get that thing checked out... I can usually rely on full manual giving consistent results but I have to go by the histogram as the metering's too wonky. Same behavior with various lenses so not sure what its problem is yet, aperture control lever calibration?.. Have to find some time for detailed testing.

Meanwhile..

My D800 does the same -1EV shift in sunlight when changing between metering modes as the K52s but its matrix mode does a very good job for all my shots and rarely under or over exposes by much in complex scenes and is predictable in low dynamic range shots.

My old Canon 5d2 often underexposed a great deal and again, inconsistently. It occasionally over exposed a scene grossly too, even with no change of scene and from shot to shot. Manual was the only way to get consistent shot-to-shot results.

my 60D and 7d gave remarkably accurate and consistently good metering (&WB) and also agreed very well with my Sekonics or sunny-16 when in manual. 40d gives consistent and predictable metering, even if not accurate.

All my consumer grade bodies, Canon and Nikon, actually seem to meter quite predictably and consistently, if a little conservative at times so they rarely clip highlites or underexpose by much.

*So... not surprised to hear that a 6D underexposes a bit.
But how consistent is it between metering modes and various light levels?* and shot-to-shot on the same scene?


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## Sporgon (Aug 15, 2013)

Good to hear the 7D2 is reliable and accurate. That's going to keep a lot of people happy in the future


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## CTJohn (Aug 15, 2013)

Aglet said:


> I've found various bodies to expose with various levels of error, no real surprise.
> 
> What I find more annoying tho, is an _inconsistent_ error on any given body.
> 
> ...


I have not had issues between metering modes and within a same scene. It's just dark, and if indoors, off color.


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## Aglet (Aug 15, 2013)

Sporgon said:


> Good to hear the 7D2 is reliable and accurate. That's going to keep a lot of people happy in the future



HAHA! Good of you to jump on that typo (fixed).
so many multigenerational devices...
Still hoping a 7d2 is going to be impressive for more than its forebear's metering.

Meanwhile, back to metering SNAFUs...


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## Aglet (Aug 15, 2013)

CTJohn said:


> I have not had issues between metering modes and within a same scene. It's just dark, and if indoors, off color.



I haven't played much with a 6D but still find that is unexpected behavior.
Everything that I've used with that 63 zone metering sensor has provided excellent metering and AWB.

Can you compare your 6D with another, side-by-side, same lens?


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## CTJohn (Aug 16, 2013)

Aglet said:


> CTJohn said:
> 
> 
> > I have not had issues between metering modes and within a same scene. It's just dark, and if indoors, off color.
> ...


No, unfortunately I don't know anyone else with a 6D. It sounds like I'm not the only one with this sort of problem from the above comments.


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