BL Blog

Is the Canon 6D Under-Exposing? UPDATE: No, It’s Not.

Gear Talk

Final Update and Winners of the Gift Certificate, Friday, December 7, 2012 11:35 AM

Okay, we found the cause of the D600 bodies’ overexposure. Turns out, it WAS damage, not a defect. In the damaged bodies, the little prong that actually pushes the aperture closed was bent, as you can see in the image below. The top one is of one of the damaged D600’s, while the bottom is of an undamaged D7000.

No idea what caused this, but there you have it.

Winners of the $50 Gift Certificate: K.G. Wuensch, who left the suggestion that led to our discovery of the cause of the overexposure on the D600 bodies is, unfortunately, not based in the U.S., and so is unable to use the certificate I promised him. He has, instead, requested that his prize be entered into the pool for the general drawing. So we now have two gift certificates to give out.

I entered all the commenters’ names into a list randomizer at and the two names at the top are our two winners.

The winners of the gift certificate drawing.

The winners of the gift certificate drawing.

Congratulations to David Johnson and Michael Clark! Please email your contact info to sohail.mamdani at borrowlenses dot com, so I can send them to you.

Once again, thanks to everyone for your fantastic support and feedback. 

Update Thursday, December 6, 2012 2:11 PM

Thanks to a suggestion from one of the folks who left a comment below, K.G.Wuensch, we found the issue that led to the big discrepancy in the images you saw from my test, and the issue turned out to be with the D600, not the 6D.

Take a look at these images. Both cameras have apertures set to f/8, and I had one of our staffers hold down the Preview button on both bodies. As you can see, the defective D600 on the right doesn’t close the aperture down as much.

We found this behavior on two separate bodies. It affects not just the Sigma lens, but also the Nikon 50mm f/1.4G lens, so it’s not a 3rd-party lens issue. We know we received at least two duds, and the warehouse is looking to see if there are any more. We will, of course, take those – and any others we find – out of circulation and send them back to Nikon.

One of the defective D600s we found on the right, the normal on the left

One of the defective D600s we found on the right, the normal on the left

On a personal note: I really have been taken aback by the level of positivity in all of our readers’ comments. When I first wrote this article, I was prepared for an avalanche of brickbats and accusations of everything from anti-Canon/anti-Nikon conspiracies, to suspicions about personal gain. By staying above the cruft, you guys are kinda restoring my faith in the interwebnets :-)

As a personal thank-you, everyone who has written a comment below as of the time of this update is entered into a drawing for a $50 Gift Certificate from Consider it my way of expressing my gratitude for your support, encouragement, and suggestions.

One commenter is not eligible for this draw, though. That’d be you, Mr/Ms/Mrs K.G.Wuensch – because I’m also giving you a $50 Gift Certificate from for hitting the nail right on the head, separately from the draw. Please email your contact info to sohail.mamdani at borrowlenses dot com, so I can send it to you.

One caveat is that you do have to meet’s rental requirements to use the gift certificates. I wish I had a way around that, since we do have an international readership, but alas, that’s not something I can arrange.

Thank you to everyone who took the time to read this piece and offer constructive feedback. It’s a pleasure working on this stuff for you.

Update: We’ve done further testing and added to this article. Please scroll to the bottom for the latest info.

We took delivery of Canon’s newest body, the 6D, late last week, and I was assigned one for testing immediately. With sunlight a rarity these days in the Bay Area (we’ve had a spot of weather lately), I resorted to shooting some night-time long exposures to start with.

Canon 6d

Canon 6d

Earlier in the day, as I was picking up gear, one of my BorrowLenses colleagues remarked in passing that he thought the 6D might underexpose things a bit. I didn’t pay much attention to this; depending on the metering mode set and the part of the composition that the camera’s metering sensor is looking at, exposure in one of the automatic modes can vary wildly. I didn’t even bother making a mental note to check on it.

As part of the 6D test, I decided to take a Nikon D600 along with me as well to do a side-by-side comparison of images. And when I saw what was coming off the two cameras in my first test I am glad I did.

My first test was shot in RAW on the 6D, which turned out to be a mistake, as neither Lightroom nor Aperture support the 6D just yet (hence no images from that test to show here). What I was seeing on the LCD, however, was enough to make me head back to the BL office and swap out the 6D body. I was sure I just had a bad copy.

So I headed out again the next night. My subject this time was the San Francisco skyline. For the images you see below, I tried to match the output from both cameras as much as possible.

For starters, I captured in RAW+JPEG mode for both cameras. I set the picture styles to Neutral on both bodies, and shot the images at ISO 100. I also used the same make/model of lens on each camera, the Sigma 50mm f/1.4.

First, have a look at the image below. This one was shot on the Nikon D600.

Nikon D600, f/8, 30-second exposure at ISO 100

Nikon D600, f/8, 30-second exposure at ISO 100

As I’ve noted, the exposure in Manual mode was f/8, 30-seconds long at ISO 100. No adjustments – other than resizing for the web – were made on this image.

Now, here’s the image from the Canon 6D, exact same exposure settings.

Canon 6D, f/8, 30-second exposure at ISO 100

Canon 6D, f/8, 30-second exposure at ISO 100

Pretty big difference, no? Here are the images, side-by-side.

Canon 6D on the left, Nikon D600 on the right.

Canon 6D on the left, Nikon D600 on the right.

Now, I’ve seen variances of .3 or even .6 stops in cameras. Sometimes, the perceived difference in exposure can be because one camera captures mode dynamic range than another (and that may well be true for the D600 over the 6D here), or because of some other reason. Certainly, cameras of one brand do tend to meter differently from cameras of another. But here, the images do appear to indicate that for identical settings, the Canon 6D does tend to underexpose its images by about two stops.

In the image below, you’re looking at the Canon 6D on the left and the Nikon D600 on the right. The images look pretty similar, right?

Canon on left, Nikon on right.

Canon at f/4, 30 secs on left, Nikon on right at f/8, 30 secs.

Interesting, here, the Canon 6D’s aperture has been bumped up to f/4. That’s a full 2 stops brighter than the image from the D600. Below, you’ll see a 100% crop from these two images.

100% crop of the 6D (left) and D600 (right) images.

100% crop of the 6D (left) at f/4, and D600 (right) at f/8.

I’m also being told that the differences you see here may also be exacerbated by the fact that this is a long exposure. I don’t know that that’s accurate, so we’ll be doing a few more shots with test targets and more “normal” exposures to be certain. I suspect that the difference won’t be as drastically apparent, but it’ll still be there nonetheless.

It’s important to note that this behavior was observed on two separate bodies. The difference was also marked between exposures on the 6D and the 5D Mark II, though since those were all shot the previous evening on RAW and I don’t have a RAW converter for the 6D handy just yet, the comparisons will have to wait. I did, however, see what I perceived to be at least a 1.5-stop difference, if not more, between the 5D Mark II and 6D images.

Even if the difference is only 1.5 or 2 stops, that can have an impact on all kinds of shooting. If you’re using a Sigma 50mm f/1.4 lens, for example, and shooting at f/1.4 at 1/60th, you’d have to shoot at 1/15th of a second to get a normally exposed image with a 6D. Your flashes would have to work harder, and your night-time long exposures could take three times as long. That’s a pretty big impact for many shooters.

So what do you guys think? Is the Canon 6D underexposing? Or is the difference more perceptual than anything else? Is this more about dynamic range than exposure? Leave us your thoughts!


A few folks have been asking about histograms, so here are the histograms from Lightroom.

Histogram from the 6D shot of the San Francisco skyline

Histogram from the 6D shot of the San Francisco skyline


Histogram from the D600 shot of the San Francisco skyline

Histogram from the D600 shot of the San Francisco skyline


I shot a bunch of new tests earlier this morning under different circumstances with a Canon 50mm f/1.4. Looking through the test results now, but it looks like at the very least, the Nikon vs. Canon differential is holding. More to follow shortly.

UPDATE 6:08 PM Wednesday, December 5, 2012

And just because this HAD to get more confusing, here is a grouping of the latest images, shot this morning.

Things you need to know:

  • A lot of you talked about the lens being a factor here. That might well be true, but I don’t yet have enough data to verify this. I did shoot the Canon images with a Canon 50mm f/1.4 lens.
  • We will test again later this week with native lenses. Someone in the comments said the Sigma might be to blame here, and right now, that’s not out of the realm of possibility.
  • These shots are in-camera JPEGs.
  • D-Lighting, Auto Lighting Optimizer, and Highlight Tone Priority were turned off.
  • Spot metering mode was used (not that this should matter at all).
  • Neutral picture style was used for all five shots.

With that, here they are.

Canon 6D

Canon 6D

Canon 5D Mark III

Canon 5D Mark III

Canon 5D Mark II

Canon 5D Mark II

Nikon D800

Nikon D800

Nikon D600

Nikon D600

And finally, all five shots, together.

Clockwise from top-left: D600, D800, 5D Mark II, 5D Mark III, 6D

Clockwise from top-left: D600, D800, 5D Mark II, 5D Mark III, 6D

So what does this mean, exactly?

Looking at this, it sure looks like it’s the D600, not the 6D, that’s the outlier, doesn’t it?

*sigh* Back to the testing room.

My initial conclusion that the 6D was under-exposing was based on its comparison with the D600. I assumed that the D600 was exposing correctly was based on my experience from the first night of shooting, where, on the camera’s LCD, it looked like the D800E and the 5D Mark II were putting out exposures more in tune with the D600 than the 6D. That may still be the case – I won’t know till I can convert those darned RAWs from the 6D.

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.

Which is also why I sincerely thank the folks commenting below. We’re figuring this out together, and I appreciate the input from all of you. I’ve taken a lot of your suggestions into account, so keep them coming. Something is amiss here, and what started as a question about the Canon 6D may yield answers about the Nikon D600 – or, indeed, the lenses used or about the JPEG processing engines in cameras and software. 

BTW, I still have had no luck converting the 6D RAWs. The Canon software refuses to install on my MacBook Pro 13″ Retina model running Mac OS 10.8.2, so I’m going to try doing so on a PC.

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Sohail Mamdani is a writer and photographer based in the San Francisco Bay Area. Follow him on Twitter, Facebook or Google+. You can find his portfolio on his website at as well as on 500px and Flickr.

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  • Eric Gould says:

    When you are shooting at night Canons and Nikons will vary the exposure time to get a correct result. Trying to match settings will not produce like results. In other words if you like the image on your friends Nikon and ask for their settings and copy those setting onto your Canon – it will not look the same. Nikon’s typically require a shorter shutter time than Canon.

    • Sohail Mamdani says:

      Eric, I can understand differences in dynamic range or white balance or even some variance in exposure, but two whole stops? I could be wrong, but that’s a pretty hefty difference. If that is normal – and you may very well be spot-on – that’s not an insignificant thing, don’t you think?

      Also, I found that there’s a similar difference in shots form the 6D and the 5D Mark II, i.e., the 6D is about 1.5-2 stops under the image from a 5D Mark II. I’ve only got RAW shots and no converted for the 6D, else I’d have posted those.

      • Eric Gould says:

        It’s Apples and Oranges. Each camera has it’s own exposure range. My numbers don’t need to be your numbers. Look at the histograms for each – my guess that regardless of the numbers the exposures look right. I am often out shooting at night and see this all the time among a different shooters on different cameras. Also, at night my recommendation is not too trust the LCD for a correct exposure. There’s a huge difference in the displays between different cameras and venders in brightness etc. For example things on the 5D Mark III look amazing and not so for Nikon. Use the LCD for composition and your histograms form exposures.

        • Raymond says:

          Eric, I don’t think you’re understanding the article. This isn’t about the camera’s LCD display, it’s about the final image being produced. The underexposed image, I guarantee, will be shifted greatly to the left on the 6D on these images because they are out-of-camera JPGs.

        • Lightmanfilms says:

          These are not apple and oranges. First of all there isn’t such thing as “exposure range of a camera”. And yes he’s settings were correct. Actually you do compare two cameras based on the same settings and same ISO. ISO was created by International Standard Organization which have created a standard for the sensor light sensitivity and it is an international benchmark for all companies that manufacture photo cameras. First of all think that the sensor has limitation of how much electricity the chip of the camera can send to it because both sensors work on same voltage. More voltage and it will burn. The higher the amperage more noise you will get. Remember, both sensors of canon and Nikon sensor work on the same voltage and have the same electricity tolerance… Canon to make their sensor to be less noisy they limited that electricity that its being sent to the sensor by compromising with 2f/stops down. So less electric charge means less noice. They also pumped up the red value giving the camera a fake boost from the RGB to make the colors look as good and warm as nikon. Though histograms never lie and trust me Lightroom works fine. That is why Nikon always had better RAW than Canon. Technically speaking they have almost identical sensor quality wise so i guess its a matter of personal preference and looks. The rest is just glass…

      • Gabe says:

        is it possible that is Lightroom doing this changes instead of the camera itself? I would suggest comparing JPEGs and see how they relate to the D600. At this moment I’m not sure if Adobe has support for the 6D

      • You used a third party lens that was reverse engineered before the 6D existed. Canon (or Nikon, or any other body manufacturer) will design new products to be compatible with their existing proprietary systems, but that is no guarantee that new products will be 100% compatible with preexisting reverse engineered third party products. I think I’d compare a Canon EF 50mm f/1.4 and the Sigma 50mm f/1.4 on the same 6D body to see what happens.
        The 5DII was available for Sigma to use when designing and testing the 50mm f/1.4. The 6D was not.

      • alene says:

        I’ve observed similar findings to what Eric described.

        Digital camera bodies to seem to have their own language for what exposure means to some degree. I’ve noticed that my d700 brightens up the image more than my 5dii on the same settings, and wasn’t surprised by your results, though I think the d600 is too markedly different. One other note, while iso capabilities have increased, I’ve noticed that between (as an example) Canon’s Rebel line, that while newer models have expanded far beyond 1600, it seems that the various settings aren’t necessarily equivalent. An old XT might seem less pressed upon to perform at 400iso, while the t2i requires a higher boost. Whatever my informal findings are, I’ve concluded that iso settings can be a little arbitrary.

    • That seems unusual.. I have a Canon T3i and a T4i, if I set them to the exact same manual settings of 1/125, f/6.3, ISO 400 and both with Speedlite flashes, they produce basically identical results in similiar lighting situations (I can confirm this as those are the exact settings I just used on those two bodies for over 500 shots on each one at an ongoing event).

      It seems to me that 10 seconds is 10 seconds, f4 is f4 and ISO100 is ISO100, regardless of what camera body you are using and there shouldn’t be that much variance between two cameras set to the exact same manual settings.

      What you’re saying is that there is some “mystery” exposure value that will make two different camera models record two different exposure values when ISO, aperture, shutter speed and focal length are all the same? I am not familiar with this.

      • Suzanne says:

        I just got a full-frame camera today, and I can say there is definitely a HUGE difference in ISO and f-stop on a full frame vs. crop sensor. So, yes, the camera body makes a very big difference in the result.

        • Chris Hunter says:

          So you’re saying that when you shoot at f/4 at 1/100th at ISO100 on a APS-C sized sensor and at the same settings on a full frame sensor, you’re saying that there will be a consistent difference in exposures?

          Please explain this…. sensor size is relative to many things such as field of view, depth of field and resolving power, but as far as I know should have no effect on exposure values whatsoever.

        • Chris Hunter says:

          “Exposure settings produce the same exposure on any camera. That’s basically how the numbers are defined. It’s a simple system allowing photographers to work with any camera without having to compensate for the equipment.”

        • Chris Hunter says:

          “Does a large bucket collect more water than a small one if you leave them out in the rain for the same period of time? Answer: yes, if you count the total volume of water collected, no if you measure the *depth* of the water in each bucket. That’s why we can say “it snowed three inches last night” without havng to specify how big a bucket we used to measure that. We don’t even need a bucket when measuring snow – we can just stick a ruler on the ground.

          What this means in photographic terms is, the *exposure* will be exactly the same whether 35mm or APS-C, because exposure is basically the depth of the water in the analogy above. But the overall perceived *noise* levels will be lower for 35mm, because perceived noise is more or less *inversely* proportional to the total amount of light collected.

          So if you shoot with exactly the same aperture, ISO, and shutter speed, you’ll get exactly the same exposure on both FF and APS-C, but less noise in the FF shot. You could also, then, choose to shoot a hgher ISO on FF, thus giving you the same noise as APS-C, but a faster shutter speed for the same exposure (or a brighter exposure for the same shutter speed).

          That’ all assuming we keep aperture the same. Of course, in order to get the same aperture (and same field of view) between FF and APS-C, you’ll often need a physically larger lens to do it: a 200/2.8 is a lot bigger than a 135/2.8.

          Sometimes, we might say a 200/4 for FF is “equivalent” to a 135/2.8 for APS-C, because if your shoot the 200/4 on FF at higher ISO, you’ll get exactly the same shutter speed *and* the same noise as APS-C. That is, while it is true that the FF sensor can collect more light overall (just as the larger bucket collects more water), it needs a much larger lens to allow it to do so. If you use lenses that are “equivalent” (meaning, 1.5X the focal length and one stop smaller aperture for FF), you’ll actually end up collecting the same amount of light (water) on both sensors.

          This was the subject of a very long thread a few months ago that I don’t really recommend reading as there was a lot of confusion and argument generated along the way.


        • Suzanne, are you comparing in camera produced JPEGs? Or are you comparing RAW files displayed on a monitor using Canon’s DPP using the same “recipe” including in-camera settings like Auto Lighting Optimizer, Highlight Tone Priority, and Peripheral Illumination Correction? Have you checked to see if the brightness level of each camera’s screen is set to the same level?

      • Kirk Bruner says:

        I absolutely agree one hundred per cent. During the film days, chaos would have been rampant if all cameras weren’t able to time a shutter speed correctly and if metering systems couldn’t have been able to render a setting for ISO (or ASA) 100. As you say, f4 is f4. If you can’t manufacture a shutter mechanism to fire off a clean one hundredth of a second, get out of the business.

        • Sohail Mamdani says:

          Kirk, I agree. I’d hate to set up lights for a shoot, only to find that one body meters 2 stops away from another. That’s frustrating. More testing in progress as we speak…

        • During the film days you didn’t have in camera settings for highlight tone priority, auto lighting optimizer, peripheral correction, etc that can affect the in camera conversion to JPEG, even when using manual mode to set exposure, either. I think Andre, elsewhere in this thread, is onto the real explanation with his suggestion it is related to an updated .jpeg conversion engine. It will be interesting to see how DPP converts the RAW files from the 6D. Canon could have just as easily written the same .jpeg engine there.

      • Sohail Mamdani says:


        Yes, you’re right in that it is unusual. That’s kind of my point :-) The results took me completely by surprise – you’re pretty spot-on when you say that “It seems to me that 10 seconds is 10 seconds, f4 is f4 and ISO100 is ISO100, regardless of what camera body you are using and there shouldn’t be that much variance between two cameras of a similar class (both full-frame, both with image processors in the same class) set to the exact same manual settings.” There should not be that much variance, and that’s what took my by surprise.

        • Chris Hunter says:

          Hi Sohail, my response was directed to Eric Gould and his claim that different bodies will have wildly different results with identical manual exposure settings. That does not make sense to me.

          • Sohail Mamdani says:

            I dug the explanation you pulled from PentaxForums. Some smart cookies over there :)

          • Chris Hunter says:

            @Sohail… that explanation regarding 35mm vs APS-C is great… I just hate to see people walking around with misinformation in regards to camera knowledge.

            Sensor / film size should have no difference on exposure — it does effect some things like field of view, signal to noise, depth of field — but not exposure values.

            I’ll be curious to see your results in the future and using the 6D against other identical Canon bodies / lenses and seeing if you still get the exposure differences. Cheers!

          • Eric Gould says:

            Yes, it does not make sense. But it’s the reality. Take any Nikon and any Canon and shoot at night with the same settings and the results will vary… Have you every tried the Sunny 16 Rule on a digital camera it doesn’t work either.

    • musica23 says:

      The exposure can vary according to the internal light meter of each camera. But let’s don’t forget a major fact which is that at night no one uses a grey card and he might be in for a surprise again. What i said though about the different exposure is 100% correct beside that this camera had a defect. Thats they way they are manufactured. Unless an engineer steps up and tells me i’m wrong. Even if i don’t use DSLR’s for my filming i am pretty sure about that and also there is no doubt that the red value is boosted on Canon cameras generally. As i said, histograms don’t lie…

  • Jim says:

    I’m surprised. Perhaps you should run this by Canon. I would love to know what causes something this radical?

    • Sohail Mamdani says:

      You and me both, Jim :-) I’m going to test under difference conditions throughout the rest of this week and get back to you.

  • Gunther says:

    It almost looks like the 6D just has a better dynamic range… How do the histograms look?

  • byrdcreative says:

    My thought would be get a hold of a 5D, use the exact same lens and settings and then see what happens. :-)

    • Sohail Mamdani says:

      Byrdcreative – I did that exact experiment. The night before I shot the images above, I shot the same scene with a 6D, D600, 5D Mark II, and a D800. On the back of the LCD, the results mirrored what I mentioned above.

      So why aren’t those images up there? Simple. I shot the whole night in RAW mode with the 6D, completely forgetting that Lightroom and Aperture can’t read that RAW file yet. So I’m trying to get my colleagues at BL to find a copy of the CD those 6D’s came with. When I find them, I will convert the RAW images to JPEG and post them here – or I’ll just drag myself out of bed early in the AM and go reshoot with all four cameras in JPEG mode.

      • Mike says:

        DPP isn’t available at for the 6D?

        • Sohail Mamdani says:

          Mike, I found the CD, but the darned software won’t install on my Mac. I’m installing an eval version of Windows into a virtual machine and will trying running the installer there.

        • You must have the disc in your drive or a previous version installed before you can install the online updates.

          • Sohail Mamdani says:

            Hi Michael,

            Yep, I tried that too. No dice :-(

            Regardless, I did find the issue, so the RAW/JPEG issue is moot. *whew* glad it’s over :-)


          • Sorry, I didn’t make it clear I was replying to Mike. If you don’t have a Canon solutions disc or already have DPP installed the updates downloaded from Canon USA won’t install on any platform.

    • But the 5D was around when Sigma reverse engineered the lens used for the test. The 6D was not. The issue of older third party lenses not being 100% compatible with newer bodies has come up before.

  • manfesto says:

    Just to explore all variables, have you tried a first-party lens instead of the sigma?

    • Raymond says:

      He used the same lens (as far as manufacturer and model go; actual differences in the lenses should not be responsible for the large difference in exposure) on both cameras, and used manual settings. A Canon lens would not affect exposure if set manually.

      The more correct evaluation would be to test any defects within the lens used, of which was tested when he used it on a correctly functioning 5DMkII body.

      • manfesto says:

        Unless there is a miscommunication between the camera body and the attached sigma lens, causing it to stop down further than intended.

        Third party lens compatibility has historically been a sore point with canon cameras (see the “dark corners” issue with the 5D3 and third party lenses for a recent example), which is why I’m suggesting testing with a Canon 50mm f/1.4 to rule it out.

  • Bill says:

    Why not test against a somewhat similar Canon, the 5D III, even in JPEG…

    • Sohail Mamdani says:

      Bill – did this, actually. I responded to an earlier comment, but here’s what I told “byrdcreative”…

      “Byrdcreative – I did that exact experiment. The night before I shot the images above, I shot the same scene with a 6D, D600, 5D Mark II, and a D800. On the back of the LCD, the results mirrored what I mentioned above.

      “So why aren’t those images up there? Simple. I shot the whole night in RAW mode with the 6D, completely forgetting that Lightroom and Aperture can’t read that RAW file yet. So I’m trying to get my colleagues at BL to find a copy of the CD those 6D’s came with. When I find them, I will convert the RAW images to JPEG and post them here – or I’ll just drag myself out of bed early in the AM and go reshoot with all four cameras in JPEG mode. “

      • The 5DII was available when Sigma reverse engineered the 50mm f/1.4 to Canon’s proprietary system. The 5DIII and the 6D were not. This type of issue has come up before. I can’t recall off the top of my head which manufacturer or lens it was, but I remember seeing one story about a third party manufacturer informing owners they could send their lens in for a firmware update to make the lens compatible with a newer Canon body.

      • Since Canon’s RAW algorithms are proprietary and at some points encrypted, when you use LR or Aperture to convert RAW files you never know if the results are more an indication of the camera’s performance or the software developer’s ability to guess right with regard to the proprietary algorithms. As you so aptly pointed out in your recent series about crossing over from Canon to Nikon, it is about the combined capabilities of the entire integrated system, and not just each particular piece. Part of Canon’s system is their proprietary RAW converter. If you want to accurately measure sensor performance on a Canon body, convert to TIFF using Digital Photo Professional and export to LR, PS, Aperture, etc for any additional processing you need to do. In contrast, Nikon does share their algorithms with DxO, so one would expect the DxO RAW convertors to be more accurate for .nef files than for .cr2 files, and may partially explain the wide disparity in DxO Mark scores between Canon and Nikon bodies that produce output at qualities much closer to each other than their DxO scores would indicate.

  • LCImagery says:

    Nikon shouldn’t be anything like this different – thousands of other tests show them to be within a half-stop exposure-wise – but I agree it’s kinda apples vs oranges otherwise. I’d suggest using 5D3, a 5D2 and this 6D, setting all three cameras to JPG with identical settings. Does Canon not ship their bodies with some kind of software that can open RAW files?

    • Sohail Mamdani says:

      LCImagery – I did shoot with a 5D Mark II – see my response to Bill’s comment above. As for the software, yep, I’m trying to nail that down. The CD is somewhere in the BL warehouse. Unfortunately, we don’t give those CD’s out with rentals.

  • mike-a says:

    Looks like the culprit could be potentially some RAW conversion/preview settings in lightroom if it is not the camera.

    • Sohail Mamdani says:

      Mike-a – I don’t think so. Those shots are JPEG straight out of camera…

      • You used a third party lens that was reverse engineered before the 6D existed. Canon (or Nikon, or any other body manufacturer) will design new products to be compatible with their existing proprietary systems, but that is no guarantee that new products will be 100% compatible with preexisting reverse engineered third party products. I think I’d compare a Canon EF 50mm f/1.4 and the Sigma 50mm f/1.4 on the same 6D body to see what happens.

  • “I’m also being told that the differences you see here may also be exacerbated by the fact that this is a long exposure.”

    The Schwarzschild effect. Different sensors will be affected differently by reciprocity failure. Also since these are jpegs how much of the differences in the final image might be due to the processing choices of the camera?

  • t-fiz says:

    You’re sure that your metering mode was the same on both i.e. Matrix, Spot, etc? I notice that in the EXIF info that the Canon’s was set to Multi-Segment while the Nikon’s was set to Spot. Just an fyi.

    • Raymond says:

      He was using manual exposure settings. 30 seconds at f/8 and ISO 100.

      • t-fiz says:

        I agree…however, even though you’re shooting in Manual mode on a Canon, it doesn’t mean that the scene is not being metered different per Metering Mode. Me and a friend of mine noticed this at an event we were shooting. I have a 60D, he has a T2i but we both have the same lens (Sigma 18-250 Macro). Using Manual mode, we both set our focal length, aperture, shutter, and ISO the same and shot the same object that was nearby and got different results. He couldn’t understand why we were getting different outputs until I noticed that he was using Spot metering while I was using Center-Weighted. When he changed his to match mine, the shots match perfectly. It was the quirkiest thing.

        • Sohail Mamdani says:

          t-fiz – that’s interesting. I’ll replicate the test with the same metering modes, but I think Raymond is right – metering mode should not matter. If it does, I’d love to know why?

          • Chuckster says:

            It might matter if the image processor is lending weight to what part of the image was metered when it does the jpg processing. I could see that. Other than that, shooting in manual the camera’s meter shouldn’t mean affect the exposure at all.

          • Sohail Mamdani says:

            Hmmm… That’s an interesting theory. I’ll test it out!

        • thejoker says:

          Actually, metering will only affect the exposure guide.

          • Raymond says:

            Yes, metering only accounts for the automatic modes. Rendering of JPGs in camera is done on the curve set in the settings menu; in this case Canon’s “neutral” tone curve.

            The reason you may have two different exposures (likely very similar nonetheless) is because you used different cameras with different sensors that collect and read the information from those sensors differently. Also, he may have had different camera settings applied, such as shadow level adjustments, etc.

          • Metering won’t affect the actual ISO/shutter speed/aperture or RAW file. But selected settings for things like in camera highlight tone priority, auto lighting optimization, etc. WILL affect the .jpeg output and how the RAW file is converted for display on the back of the camera.

  • PondViewer says:

    Is it possible the D600 is overexposing?

    • Raymond says:

      He said at the end of the article that the same, if not a greater, discrepency was viewed in comparison to a 5DMkII body.

      • Sohail Mamdani says:

        That discrepancy might not exist, or it might be based on what I saw on the camera LCD, which is why I added that those comparisons would have to wait till I got a RAW converter for the 6D. Regardless, _something’s_ going on, and PondViewer might be right about the D600 overexposing…

  • Chuckster says:

    I would accept t-fiz explanation to go for. Regardless…. it’s ISO for a reason. Because its a standard, an international standard, from the International Standards Organization. All camera’s should meter the same. x fstop @ y shutter @ z ISO produces an accurate exposure with w amount of light. If you didn’t have these standards, things would be all over the place. ISO 100 is supposed to be ISO 100 on a hassy, Nikon, Canon, Phase, sekonic, Fuji velvia, kodachrome, yadda yadda yadda. And yes, minor variations are allowed in the standard, but 2 f/stops is ridiculous.

    • Sohail Mamdani says:

      Chuckster – yeah, that’s kind of where I’m coming from. I can and have seen variances of .3 to .5 stops from camera to camera, but 2 stops is, well, as you said, ridiculous…

  • Interesting conversation.
    A few valid points to consider in your retest as we don’t have Adobe or Aperture support for RAW yet, so you are forced to ensure a few basic test control standards;

    – Use Canon bodies to compare, the 6d and a 5dll or lll, to remove the cross manufacturer and full frame vs crop sensor argument, also so in-camera auto processing of the jpg would be at least similar.
    – use only Canon a lens – 50mm f/1.4 lens for both, or anything that is already calibrated in the 6d body to function properly, to deal with any body/lens miscommunication.
    – I’m sure its good, but double check to make sure you have the most up to date firmware on both bodies. Ya never know.
    – As well as outdoor low light shots like this, do indoor studio severe low light, long exposures with test targets, in other words, control all aspects.
    – Even (using mr. t-fiz suggestion) use the same metering mode.
    – Why not check the 6d custom function menu to make sure you have parallel settings, if its brand new, its possible that factory settings is the culprit.
    Very interested, let us know.

    • Sohail Mamdani says:


      All excellent suggestions.

      *sigh* I guess I’m getting up early in the AM :-)

      • Ha, then get to bed, you gotta big day tomorrow, lol.

        If you cant get the disk then go here and get the software from Canon, you just cant beat a RAW test.

        And if lens communication is still an issue, so ya know, Canon is kitting it with the 24-105, so that HAS to work. Not the best for a test, but it should be guaranteed to work. actually nix that, if its calibrated to that lens, its calibrated to a basic prime as well, never mind, just considering options.

        Now go to bed Mr. Mamdani, you are carrying the weight of many Christmas shoppers on your efforts tomorrow, we need you rested … tell the boss you need to sleep in late … modding a forum, testing product … beauty sleep needed … we’ll back you up. 😉

        • Sohail Mamdani says:

          Well, I woke up dark and early… to rain. Lots of it. Forgot that we were getting a storm overnight.

          I’m heading into the BL office later this afternoon to test the cameras indoors, with ambient and strobes. I’m very curious to see what it does under those circumstances.

          Much appreciate the backup 😀

  • Marvin says:

    Just from the perspective of shooting a night skyline, the 6D images makes more ‘sense’ to me. Properly exposed lights, etc and dark sky/water. What do you all think?

  • Evan says:

    Some food for thought….did you have the HDL feature turned on. In essence, it underexposes the shot by 1 stop and its tagged in the raw file to tell the raw converter to push up the exposure and such. If you have this feature turned on and the raw converter you’re using isn’t ‘pushing’ the file, you see the actual exposure for said file.

  • Andre says:

    Every camera has an ISO that’s slightly off from the “true” ISO. However this is way beyond that variation… I can’t see Canon producing a sensor that far off by design, and it seems like this would be easy for QA to detect. My guess is that the jpeg engine of the 6D is very different from that of the 5d2 and d600. Likely the 6D is lowering the blacks to get more contrast, and the d600 is raising the blacks to get more DR.

    I wounder if this is a property of digic 5’s jpeg engine? How doesthe 6D and 5D3 ccompare in SOOC jpegs?

  • Ok.. the histograms … these were still from camera processed jpegs, right? What about the RAW files? How’s the in camera histogram on those?

    • Sohail Mamdani says:

      Too late to tell now, texasphotochick. The cards were offloaded and wiped already. I’ll snap shots of the screens when I reshoot.

  • r.r. says:


    Active D-Lighting was on or off?

    The RAW´s from the D600 could you open with Capture One 7 Demoversion.

  • John says:

    so….every canon camera shoot like EOS 6D , does D600 over exposure ?

    • Sohail Mamdani says:

      John, my 5D Mark II shot more like the D600. I’ll update the article with those files once I have the RAW converter for the 6D…

  • r.r. says:

    and 6D too

  • PondViewer says:

    Was exposure compensation on?

  • Andre says:

    Just thinking a little more about this now. If you want to get similar jpegs, I’d recommend turning off “Auto Lighting Optimizer” on both Canon cameras, and “Active D-Lighting” on the Nikon. That should result in less processed jpegs, and be more accurate. Canon changed their jpeg engine between the 5D2 and the 5D3/6D, so that could be causing the difference. Those lighting “optimizers” can boost shadows by as much as 2 stops, so that could be all we are seeing here.

    • Andre says:

      In support of that hypothesis, notice the that highlights are more blown out on the Canon 6D shot at f/4, than the Nikon at f/8. The clipped highlights can’t be taken down by exposure optimizers, so seeing them more blown out on the f/4 image is expected and consistent with the ideal they are both exposing about the same.

      Unless you go and turn them off, the lighting optimizers are on by default. So if you don’t remember turning them off, most likely they were on.

    • Sohail Mamdani says:

      Andre, D-lighting was turned off on the D600, and the lighting optimizer was also turned off on the Canon…

  • So, I have a 6D. Did some RAW shots with that and a Canon 20D and there are the same results. 6D was 1-2 stops darker, viewed on screen and the histogram. I have to admit that although overall it was darker, the brights (at least in this one shot image) seemed to be at a very similar level. I am wondering if the 6D just boosts the darks in an effort to make more contrast.

    In the mean time, good thing the cameras high ISO is so good, since if this is something terribly wrong Ill need to shoot at a higher ISO sometimes to get the optimal shutter/aperture. Thanks Canon!…

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  • i use a canon 60d the iso is around 3200 and fstop is always 5.4 and the pic’s come out great.i have even shot photos in sports mode in the dark and they come out fine.

  • Kera says:

    I have a 40D (yes I know old school) and I have been saving to buy a full frame camera for awhile. I was excited about this camera comeing out beciase I was going to buy it over the 5D since I mostly shoot my kiddo and crime scenes. BUt now this is making me worry about my choice! Back to playing the waiting game :(

  • Voytech says:

    I believe that the ISO may be the culprit here. Canon is known to use lower true sensitivity and label it higher to achieve “better” noise/dynamic range results. This would be extreme in this case.

    What I’m saying is that the camera is showing ISO 100 but its really closer to 50 or 80. DXO mark explains this here:

    • That wouldn’t explain 2 full stops. I doubt ISO100 on the 6D is really ISO25! I think Andre is on the right track with regard to the updated JPEG engine.
      Remember, Canon does not share their proprietary encrypted RAW algorithms with DxO. Nikon does. Any DxO result with regard to a Canon sensor is as much about how well they managed to match Canon’s algorithms as it is about actual sensor performance.

  • Sohail Mamdani says:

    UPDATE: I just shot a bunch of new tests earlier this morning under different circumstances with a Canon 50mm f/1.4. Looking through the test results now, but it looks like at the very least, the Nikon vs. Canon differential is holding…

    • Ed says:

      I think that either RAW file (Canon 6D or Nikon D600) would yield an acceptable file once you have software to process those files. I know this is irrelevant to the point of this article (exposure differences) but, in practice, one often works with RAW files that don’t look great in JPEG. Sorry to take us off topic into one stop bracketing.

    • Were your test shots this morning also long exposure, or is there a difference with briefer exposures as well?

      • Sohail Mamdani says:

        Michael – It was an ambient light test under tungsten bulbs. I went with ambient to shoot longer exposures. I’ll be doing a test with strobes later tonight or tomorrow.

  • Andre says:

    Interestingly Canon seems to default to ISO 400 for bulb exposures (according to the manual)… I wounder if this is the reason for that? Maybe the sensor doesn’t handle long exposures under ISO 400? Pure speculation, but it would be worth testing I think.

    Looking at examples from other sites, I haven’t seen this issue at lower shutter speed tests.

    It would be neat to see tests done at ISO 100 and ISO 400, as well as with short exposures and long exposures. Maybe when I get my hands on this camera later this week I’ll give that a try….

    • Sohail Mamdani says:

      Andre, that’s interesting. I shot my test images I’m Manual, not Bulb mode, but I reckon that the longer shutter speeds might have something to with this issue too. More updates on the way…

  • Hi over there, Ill guess that Canon has a good explanation to you. Its a bug in the software :-) Next sw update will fix it. My guess is that the ISO range is set wrong from Canon. Love to follow your results. Rune from Norway

  • Dudley Carter says:

    As a product shooter, I’d propose a studio test for this issue. Set up a test card, like the passport color checker, and using a good studio incident meter, light it for say, 1/250th at F/8, ISO 100. Look at the results. If the difference still exists, something is really wrong. If the difference has disappeared, it may have something to do with low light situations, which could then be tested using hot lights so that lighting could be set for say 1 sec. at f/8 and then 10 sec. at f/8.

  • Shooting says:

    Try testing with proprietary lenses of the same focal length and aperture. The first pair leaves me wondering as to accuracy. The second pair looked like the 6D was brighter by far. The final pair with the two step difference was no where’s near identical with the Canon much brighter. I’d go check out your gear and methodology for consistency. Anything done by a private corporation for pay will vary by a large extent and i don’t know what connection have with either of these. Generally people put too much emphasis on these sorts of things. Like comparing features in a new model and than determining for all the updates they’re virtually the same. It’s just too picky to bother with this when in fact there is no independent test analyzer. Thanks.

  • mhpit says:

    Hi, for RAW processing at the moment, you can try capture one 7.0.1

  • Andre says:

    Did you have any lens corrections turned on? I remember there was a strange issue posted a while back where a Sigma lens gave white corners because the camera thought it had a different lens on it.

  • David says:

    I just got my 6D in today and I tested it side-by-side with a 5D3 and 60D. All three cameras are exposing well within 1/3 stop of each other. Seems you’ve already found the Nikon to be the problem, though.

    • Sohail Mamdani says:

      Certainly looks that way for the moment, though some folks in the comments say the 6D is indeed underexposing. We’re gonna test this exhaustively through the rest of this week and even use a Sony A99 as a control subject…

  • John Matthews says:

    Just a thank you. You are doing a lot of grunt work. You have very interesting findings and I am fascinated by what is going on. I am also holding off on an upgrade.

  • K.G.Wuensch says:

    Isn’t the aperture control on the Nikon/Sigma-Lens combination via the (rather crude) mechanical lever mechanism on the Bayonet? Just have a look at the reaction of the aperture blades with the DOF control button on the D600, maybe the blades don’t close as much as the camera thinks they should – which is a rather common occurrence as the lever mechanism is subjected to a lot of wear…

    • Sohail Mamdani says:

      K.G., that’s something we suspect, too. That’s why we’re swapping out the Sigmas for native lenses, 50mm Canon and Nikon versions. More tests to come.

      • K.G.Wuensch says:

        Why don’t you do the small test with the DOF control as I suggested, then you immediately have confirmation if the aperture control is off…

  • Marshall says:

    Interesting article. I guess it just goes to show that one should always take multiple shots – while adjusting settings in between – to ensure proper exposure.

  • Thomas says:

    Thank you Sohail for all your hard work! As someone that’s potentially upgrading in the next few months, this is extremely interesting. I too assumed the same as that f4 is f4 and so on, no matter the camera. That being said, regardless of whether or not its the 6D under-exposing, or the D600 over-exposing, I’d also assume that a fix can be issued through a firmware update.

    One thing that interested me though is how the 6D appears to be way less sharp than the D600 in the 100% crop images…

    • Sohail Mamdani says:

      My pleasure, Thomas! Also, I noticed the sharpness too, but bear in mind that these are in-camera jpegs in the Neutral picture styles. The RAW files may allow sharpening to a much larger extent.

    • The difference between f/4 and f/8 would explain the apparent difference in sharpness.
      If you look closely at the mid tone areas at the water’s edge you can see that there is not a lot of difference in sharpness there. What appears to my eye to be happening is that the highlights in the Canon shot are a little blown, which makes it look like the focus is soft. I have many overexposed, high contrast, shots of my own where blown highlights make the focus look soft. 😉 The other consideration is that the Nikon was shot at f/8. The Canon was shot at f/4. Depth of field will be shallower. If the plane of focus is in the area at the water’s edge, as it appears to be, then one would expect the lights that are further back to be less in focus at f/4 than at f/8.

  • Allan Aylard says:

    If you have now shown that the issue is with the Nikon D600, could you please change the title of the article. People may not read the entire article to see the update and reach the wrong conclusion. The update should be at the top of the article.

    • Sohail Mamdani says:

      Allan, just as soon as I’ve confirmed it definitively in the next day or so, I absolutely will change the article headline. I will add an anchor link to the update notice at the top so people can click through to the update.

  • Just returned from Cambodia using both a Nikon D800 and a D600. I noticed the overexposure in the D600 after a day of intense shooting. In order to correct the files to look similar to the D800 I started shooting minus 2/3 to 1-2/3 under exposure to make acceptable shots. Just my experience with my particular camera.
    K. Nelson

  • Fahrertuer says:

    Just a weird thought about the aperture issue of the D600:
    Maybe the debris that has been reported on some D600s (or other dirt) got on the contacts in the lens mount.
    The way the aperture is set in the camera is still mechanical and the camera depends (now – with older cameras it was purely mechanical) on the circuitry in the lens to report the largest aperture so the camera can move the aperture lever on the lens the right amount to set the selected aperture.
    I remember that my dad had a similar (maybe the same?) problem on his old F601 that was caused by a small sliver of metal that short circuited two of the contacts in the lensmount

  • Wow… not the outcome I was expecting. It’s good to know though. And a good reminder in situations like this that just because it looks like one problem in the beginning doesn’t mean it’s not something totally different. Kudos to you guys not only for following through and trying to figure out just what the heck is going on but for considering that your first impression might be incorrect. Too many of us have egos that are too overinflated and they stop us from seeing that we may not have read the situation right the first time.

    • Sohail Mamdani says:

      Thank you for the kind words, texasphotochick. Finding out I was not right in my initial assessment was groan-inducing, but going through everything and finding the root cause was totally worth it (even if it eventually turns out to be nothing more than a couple of bad copies rather than a widespread issue, it prevents those bad copies from going out to our customers)! :-) My kudos to you and the rest of the commenters here as well; I’ve actually gotten emails marveling at how civil everyone here as been! Makes me feel a WHOLE lot better about slogging through this process…

  • […] this time by, is a possible aperture stop-down issue among some D600′s.  Click HERE to read the article.  At first, they believed the Canon 6D was just under-exposing everything in a 6D vs D600 […]

  • […] small progressing today, we reported on how Sohail Mamdani of BorrowLenses had discovered that one sold Nikon D600 he was contrast was consistently overexposing photographs by dual stops. […]

  • […] en “Fotoactualidad”  ;  Original en “Borrow Lenses” Tagged with: DSLR • Nikon • […]

  • Harry Yuan says:

    I agreed. Although it is not easy to compare exactly what happened in dark scene, I personally did not have any problem shooting with Canon 6D at night.

  • I recently upgraded from a Nikon d50 to the d600, and while I love the camera, I found your post because I’m having serious metering issues in the other direction. It’s consistently significantly underexposing the images. I can compensate, but I’d rather have my new camera, you know, work.

  • gollav says:

    Mine looks exactly the same! I just received the camera last weekend and when I tried to use the 50mm 1.8d, I was having aperture issues I saw the issue and google brought me here! The lever in my camera is bent exactly like in your picture. Does this mean Nikon will say it is not covered under warranty?

    • Sohail Mamdani says:

      Great question – We haven’t had an answer from Nikon yet, but I certainly hope they do cover it. Did you talk to the guys at Nikon?

      • gollav says:

        well, they said any bent lever issue is not covered under warranty, hmm, so, I had to use pliers to straighten it out. All my lenses are Nikon and I have used them on my D40 and D90 and bought FX lenses most of the time. I am surprised that my lenses would damage that lever! I hate to blame Nikon since I love the camera’s but this sucks. I have a quick question for you and please respond if you have a minute, in Live View Photography, Aperture priority mode, if I change the aperture on the lens from 2.8 to 22 and take a shot and then change it back to the 2.8, the aperture does not seem to be reset on the lens and if I physically notice the opening on the lens, the shutter is left with the same opening at 22. So, it narrows down but does not expand. I tried another lens (24-85) with the same result. Then, I tried the same thing with my D90 and it was reset after each shot. Is this related to the Live View Movie mode where you cannot change the aperture or do you think my camera is defective? Thank you!

        • K.G.Wuensch says:

          Could that behavior be the reason why the lever is bent? Since the lever is now extended to keep the aperture closed it could well be damaged if you remove the lens without turning off the LiveView…

          • vgolla says:

            well, I did not remove the lens in live view. I was looking at the lens shutter while it was still attached to the camera. The LCD was dim,so, I was looking at the aperture opening to see if enough light was coming through and that is when I noticed it.

  • […] little earlier today, we reported on how Sohail Mamdani of BorrowLenses had discovered that one particular Nikon D600 he was testing was consistently overexposing photographs by two […]

  • Drago says:

    I have purchased D600 a month ago and it ruined my vacation. Most of the photographs were overexposed and in some cases I had to compensate between 0.7 eV up to even 1.7 eV. The issue seems to be worse when objects are dark. Auto mode is unusable as camera is popping up flash in a bright sunny conditions.
    Before returning camera to the store I have searched internet for the issue and found this and other blogs confirming my oppinion that camera is piece of shit and I am switching to Canon. Nikon should have never released something like this as now I have no confidence in them at all, and I bet I am not the only one.

    • Daniele Bonaglia says:

      The problem happens to me too, pictures are really overexposed and the camera gives an err message. The first problem has happened whan I’ve controlled depth of field…. My camera has always benn kept in grat condition so I exclude that i have damaged it…..

  • G. MURPHY says:

    CANON 6D SET TO ISO 100, f/8, @125.
    MULTIPLE TESTS WITH CANON EF 70-300 4-5.6 IS USM, EF 24-105 F4 L IS USM, AND EF 85 F1.8 USM.

  • jay says:

    From my experience 6d is underexposing a bit. Just by looking similar setting side by side to 5d or 60 70 d easily make out . Every picture you look for more clarity. Its dim . It is more of a problem during overcast time. Excited about low light capabilities people tend to not notice that. Its more evident in side by side comparison.

  • André says:

    Sohail, por acaso você teria uma noção de quanto sai para arrumar esta peça na nikon d600. A minha está com esse problema. Muito obrigado pela dica.

  • André says:

    Sohail, by chance you have an idea of ​​how to straighten out this piece in the nikon d600. My problem is with that. Many thanks for the tip.

    • Hi André,

      We actually had to send that out to Nikon to get fixed. There’s no good way to do it without risking further damage to your camera.

      • André says:

        Thanks Sohail.

        This problem happens to anyone who turns the lens backwards. As if to Canon. When she bends back pin diagrafgma. The ideal is not to confuse the movement of putting the lens.

  • Lanye Bush says:

    I’m a bit late to the party, but I’m curious if you have any more input on the D600 exposure issues. I’ve noticed a bit of inconsistency myself.

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