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Canon T6 Sensor Issue

Published April 30, 2015

NOTE: As of May 8th, Canon has issued a recall of affected units. My hat is off to them for superb Customer Care. I didn’t dream it could be done this quickly. 



Every once in a while we notice something, because of the large quantities of cameras and lenses we buy, that we think people should be aware of. This particular issue won’t affect our renters; we’ve sent the affected cameras back. It may not affect very many people at all, since this is from a relatively small sample size. But I still think it worth mentioning.

The bottom line is that 4 of the Canon T6s and 2 of the T6i cameras we received had to be sent back because of a defect in the sensor stack (the layers of filter glass over the sensor). This is out about 10 copies of each; the others were absolutely perfect.

The affected cameras all had a dramatic pattern that at first we thought was oil or dust on top of the sensor glass.


Affected Canon T6s sensor, Lensrentals.com 2015


But when the techs couldn’t clean the ‘dust’ off, they alerted us. Closer examination with a 10X microscope show the spots are inside, within the stack and under the top layer of glass. I would assume it’s a defect in the adhesives used to put the layers of glass together, but I don’t know for certain. One person has suggested there may have been dust on the glass when the adhesive was applied, which seems logical, but again, I have no real knowledge of how it happens.

The affected cameras all looked exactly the same, so I won’t bore you with more images. It’s quite easy to see, even without a sensor loupe, so don’t make yourself crazy trying to find it on your camera; if it’s there, you’ll notice it. Actually it’s easier to see without a sensor loupe. Angled light seems to show it up very clearly, lights shining directly down on the sensor not quite as much. The other cameras had no signs of this at all, so it was either a ‘yes’ or ‘no’ situation. We didn’t see any cameras with just a few dots.

We took a number of images to see how much they would show up on an actual photograph. In wider aperture shots, as you’d expect, they don’t show up at all. At about f/11 to f/16, taking pictures of sky, clouds, or a well-lit white wall, they do become apparent, but they aren’t as bad as I would have expected.

They’re also have a very different appearance than dust on the sensor does. These have have a ringed, or target appearance rather than the dark blob that sensor dust has. Below is a 100% crop from the corner of the camera with the sensor pictured above. Remember, this is an f/16 image of a clear sky. In a regular photograph at wider apertures I doubt you’d notice it.


f/16 sky image from affected camera. Lens rentals.com, 2015


Here’s another image that is contrast boosted quite a bit, showing the bulls eye pattern a bit more clearly.


Contrast enhanced f/16 photo showing the pattern is very different than dust on the sensor. Lens rentals, 2015


All of the cameras we received had early serial numbers, and there is not going to be a direct serial number correlation with the problem. For example, we had 7 cameras in the SN 0220310007X range. Cameras with the last digit of 2 and 4 were affected, but 3 and 6 were not. That’s not surprising, really, since sensors would be manufactured somewhere else and then placed into the camera during assembly.

I’ve talked to people at Canon about this issue and they are aggressively looking into it. It will take some time for them to figure out what the issue is, where it occurred, and what cameras might be affected. They’re actively looking into the situation. They are NOT telling me, as some manufacturers do, that there is no problem.

My guess, and it’s just a guess, is that a bad batch of sensors were made, quality control missed this, and they got put into cameras. How big is a batch? I have no clue. Maybe it’s just a few hundred and we happened to get a lot (all of the cameras we’ve received have been pretty close in serial number). Maybe it’s thousands. Time will tell and I’m comfortable the problem is being addressed.

Oh, and for those of you who want to bash Canon quality control over this, well it’s appropriate, I won’t stand in your way. But I can’t because when I looked at these cameras myself the first time, I missed two of the ones with bad sensors. Like I mentioned earlier, direct light through a sensor loupe didn’t reveal it nearly as well as an angled spot light did. It’s possible the inspection of the sensors after assembly is done using a direct light, or some other automated equipment that isn’t capable of seeing this.

So I’m not throwing any stones out of my glass house. And having dealt with many manufacturers concerning many issues over the years, I’m just pleased that this issue is being taken seriously and investigated immediately. That’s not always the case.

In the meantime, check your new T6 when you get it, return it if you need to.

Roger Cicala and Aaron Closz


April, 2015


Addendum: I originally speculated that the problem might be in the adhesives used between layers of glass in the sensor stack. Several people, at least one of whom is an engineer in the industry, have emailed to tell me it appears much more likely this is a defect in the sputtering process used to coat the glass in the stack. Assuming this is the case, the problem would be visible immediately, it’s not something that would show up later after originally appearing normal.



Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

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  • Just bought mine today at Best Buy. Noticed some specs on a processed photo and my heart sank. There they were. Going back.

  • Akash

    hi Roger did all lens showed up this issue and which lens did you use for this test

  • Akash

    I think this issue is only in the Rebel model sold in U.S . I believe that Canon EOS 760D won’t be having this issue as they are manufractured in differently.

  • Alpha64

    My T6S (0120310021XX) seems clean. I checked the sensor by looking at it with angled light, and took a few shots of the sky at F16, and it looks perfect.

  • J. Evidon

    It looks suspiciously similar to the sensor corrosion issue found on the Leica FF CCD sensors on the M9 series. Leica replaced the sensors free of charge. I also had a similar issue many years ago on my Nikon D70s. I results from the glass itself corroding.

  • Joe

    I noticed the same problem on my new 760d (obtained from overseas). This is probably going to be a wide-spread problem on early production cameras.

  • Ed Magowan

    Nearly uniform size and distribution, likely not a dust issue. HEPA filters at the fab location would have caught something this large.

  • Eric Swenson

    Well, serial # 306 has it too.

  • ed in nj

    I’ve seen the same thing on every Nikon sensor I’ve owned, under one specific condition: shooting macro, highly stopped down – f32 or more. Not nearly as dense as this, but I saw it on my D100 and thought that something went wrong with my camera, and I could go right now and shoot a couple shots with any of my D800e bodies and produce something that looks like this. Willing to do that if you’d like.

  • Andrew

    It looks similar to the problems with the Leica M9 sensor. Sensor delamination I think.

  • Gavin

    Those look like fungus spores to me..

  • Thanks Roger. I have the same type of problem with my Canon 400D. This didn’t show up for the first few years. My sensor has the exact same pattern of dots that can’t be cleaned off, so I’m assuming that it is just under the first layer of glass. What makes things worse for me is that I shoot a lot of Macro….starts to show pretty bad around f/11. As mine took years to show up, I doubt it’s the adhesive.

  • It’s MEASLES!
    Our T6s has measles; our T6i does not.

  • Richard

    How did the red blood cells of a frog get into the sensor? 🙂

  • JohnL

    It’s also possible the dots take a while to form, perhaps as some adhesive finally cures, so they were okay when inspected. Now that would be a pain for Canon…

    Roger – have you looked at your EOS-M3s (if you have them)?

  • “Bulls eye pattern”????

    Must be Lyme disease!

  • sven

    From the picture you show I would almost rule out the hypothesis that it could be dust caught between layers during production. The pattern of the dots is far too regular for that.
    (I won’t go into the statistical details, but if dust settles on a surface, you can assume that each particle settles in a position independent of each other. This would lead to much more variation in the distances between the particles even under “perfect” dust settlement conditition.)
    The process that lead to the pattern you show clearly favours a certain distance between particles, which means it must be something that goes on on the surface. As you said this could be something going wrong with the glue.

  • Andy


    quick question about cleanin sensor on Sony A7II. Is it safe a wet cleaning with sensor swab and eclipse solution ? Im asking this because A7II has IBIS so the sensor is not “glued” on camera body unlike most.
    Does it require different cleaning method because of the IBIS ?


  • wootang

    a user over on the dpreview forums had the same issue on his t6i……………

  • Scott Burgess

    Thank you, Roger for the great information. Kudos to Canon for working to track the problem down.

  • Scott Burgess

    Thank you, Roger for the great information. Kudos to Canon for working to track the problem down.

  • It would have been awesome if you had created those close-up photos using one of the clean T6s’s and an MPE-65 to shoot the photos, LOL. 😉

  • A

    Could the bullseye pattern just be an artifact of clumsy sharpening applied by the camera?

    Bullseye = spot + sharpening halo?

  • Looks awfully familiar… In fact, just like the Leica sensor corrosion we reported on last year:


  • Wondering if the EOS M3 is having the same issue. I think it has the same sensor. Mine is working great, it’s a fantastic camera.

  • Amazing job Roger !
    Thank you

  • Mirrorless

    Does this issue affect also the EOS M3? The sensor on it is the same.

  • Lee Saxon

    Glad they’re being straight about it. Some people I won’t name deny their camera has an oil problem on the sensor AND then screw people who bought it by releasing a new camera to fix the issue rather than doing repairs. And the same people are apparently denying that their new 300/4 had a recall over a minor VR issue.

  • Arn

    It reminds me about the Pentax K-5’s sensor stains issue, but less severe.

  • ksgal

    Thank you Roger!

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