Canon 6D Under-Exposing?

[ThuiQuaDayNe]

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?

Canon has their own iso compared to Nikon, if you look at I-R  http://www.imaging-resource.com you can se that Canon sensor sensitivity /meteringsystem  is not like Nikon. IR test target and middle  grey shows that Nikon can be  exposure up to 1 stop shorter  , if Nikons metering and sensitivity allow us to exposure 1/1250sec  Canon must be exposed 1/760sec, almost a  1 stop more.
This is a problem, if we compare noise/resolution etc at a given iso.
Example, Canon is more like 6400iso (time/f-stop) when Nikon and Canon are exposed after 12800iso because Canon  need to be exposed longer  1/760sec instead of 1/1250sec as Nikon
So if we will compare sensitivity, middle grey, stops up to clipping , Canon are almost 1 stop less sensitive compared to Nikon if we are using same time / f-stop and  middle grey are placed in the same way and up to clipping. Therefore I always are little bit curios when people are comparing cameras and for example high iso -are they exposed after the same settings time/f-stop ??
here is d800 6400iso and 5dmk3 6400iso

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

[Martin]

...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.

[Martin]

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.

[Martin]

trolling? I am writing about the facts only.

[PVS]

...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/

[rpt]

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

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.

[ThuiQuaDayNe]

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

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.

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?

[CharlieB]

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. 

 

[Area256]

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.

[hemidesign]

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

[Martin]

...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/

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 ?

[PVS]

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.

[skitron]

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...

[justsomedude]

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.

[Wildfire]

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.