The Sky is Falling and the Light is Leaking: The A7r Anti-Massacree

Anti-Massacree — A humorous anti-war movement from the 1960s, suggested in the Arlo Guthrie song Alice’s Restaurant. The song, like many of my posts, was criticized for being overly long.

Believe it or not, I’m mostly a lurker in online forums. I read the hysteria of the day mostly for my own amusement. Sometimes I type a response but I almost always delete it. Interjecting facts into one of the daily hysterical rants would be about as welcome as a cat at a dog show. Usually I don’t even go that far. I just think there’s a lot of people online without much to do and go back to work.

That was my initial response when people started talking about light leaks in Sony A7r cameras. Let me think this through. If you shoot a 30 second exposure at ISO 25,000 into the sun or with a studio strobe aimed at the camera, you get a light leak. I do that … let me think … never. And this isn’t my first rodeo. I’ve noticed there are light leaks in lots of cameras if you look for them, and most of them were apparent without jumping through all the hoops it took to produce them on the A7r.

Judging from the various forums, however, at least a million people do that all the time and therefore this presented a huge problem to their style of photography. The amount of hysteria over leaking sunlight made me think I’d stumbled into the forums. I wasn’t getting involved in that for love or money.

But Dave Etchells and the crew at Imaging Resource have shown in a series of articles that there probably are some real-world implications for some photographers. When Dave asked us to take a look and see if we could find causes and workarounds, we did just that.

Testing Setup

The light leak has already been documented quite well by Imaging Resource, Ferrell McCollough, and others. We tried a couple of simple methods to determine where the light leak occurred and found something that seemed pretty accurate. We took the fiberoptic light sources from our microscopes and shined them at various points around the camera mount with either lens caps or lenses mounted.


We found at ISO 25,000 and 6 second exposures we could reproduce the leaks quite readily. More importantly, we could see the leaks varied depending upon which quadrant of the mount we shined the light on, with no leak from certain areas and spectacular leaks from others.




Here’s what we found:

  • We tested several A7rs and several A7s and all were the same, so it’s simply a design issue, not a batch of defective cameras.
  • The light leak occurs with the body cap in place, but is more severe with a 35 f/2.8 Sony lens mounted instead of the body cap.
  • The leak is worst when the light is shined onto the lens-release button area. It is also bad when the light shines onto the lower left quadrant of the lens mount, and directly above the lens mount. Other areas either didn’t leak or showed only a thin line that was far less pronounced than these areas.
  • Wrapping something around the lens mount stopped the left side leaks, but not the leaks around the lens-release button.

Taking the metal mount off of the lens gives us a bit more information. The red lines show the areas of greatest light leak. Obviously one is around the lens release button. There’s a gap under the mount at the top that may explain why that area has more of a leak. The lower left area doesn’t show any obvious explanation as to why it might be worse, though.


We went back to our test lights and placed the fiberoptic lights over the lens-release button and screened them from the rest of the camera to see if we could actually see the light leak in this area. We were a bit surprised to find there was almost a direct reflection down onto the sensor. This image isn’t the greatest, but you can clearly see the light that was shined onto the button (it’s behind the black mask at the top of the picture) is reflecting back off of the sensor assembly (violet and green bars).


Quick Fixes

Obviously putting a scrunchy around the lens mount, as Ferrell McCollough has suggested, helps a great deal. My thought, after looking at the front with the mount removed was that putting some optical black on the back of the mount might reduce reflections from the aluminum, so we tried that. Epic fail – it made no difference at all.

We assumed a weather-sealed lens, with a rubber gasket, would work well, too. But we don’t have any weather sealed FE lenses available. So Aaron decided to make a bit of weather sealing around the lens mount, using some single-side adhesive rubber material (electrical tape) we keep in our high-tech lab. A bit of time working under a magnifying loupe with a scalpel and forceps and he had made a nice weather seal.


Once it was placed back on the camera, lenses mounted nicely and the light leak from the top and left sides was almost totally gone. It didn’t do diddly squat about the light leak around the lens-release button, as we expected.

Here we were faced with a conundrum. We could completely disassemble the camera to get to the lens release mechanism and hope some obvious solution became apparent (this was Aaron’s initial vote). But about this time Officer Obie wandered into the repair area and made some ‘suggestions’ about us actually fixing some stuff that was awaiting repair. We told him, in two-part harmony, that we had been tasked with a Holy Quest and explained the ISO 25,000, shooting into the sun, 30-second exposures, fiberoptic light testing, and the special rubber lens-mount weather seal we’d made. He just said, “Kids, get back to work.”

So, instead of completely disassembling the camera, Aaron invented the ‘lens release button light seal’, again using some special flexible lightproof plasticized sealant patches (electrical tape) we had.


I wouldn’t call it elegant, but it worked just fine. There were absolutely no light leaks now and once we trimmed the tape back off of the lens, the release button worked fine through the tape.

Practically speaking, I don’t recommend making your own weather seal around the lens mount. It takes a while and you have to take off the front mounting plate so your warranty is voided, etc. A scrunchy or such will work just fine for those times when you just have to shoot at ISO 25,000 for 30 seconds, take long exposures facing the sun, etc. If the thing you use doesn’t cover the lens-release button, then a bit of electrical tape will handle that just fine, too.

And for you Fanboys who just can’t wait to Sony bash over this odd little issue, let he whose camera is without light leak cast the first stone. Because, so far the same problem has been found with Canon, Nikon, and Fuji cameras. I assume a similar solution will work just fine for those, too.

Roger Cicala and Aaron Closz, the boys from the Group W bench.

About the author: About the author: Roger Cicala is the founder of LensRentals. This article was originally published here.

  • lord eels

    sony what a crap

  • Vlad Dusil

    This issue is blown way out of proportion by the same people who generally indulge in complaining A LOT. Realistically this has such little impact on the way that the vast majority of users take pictures.

    Why in the f*** would you be shooting at ISO 25k with an abundance of light BEAMING RIGHT AT THE F***ING CAMERA. Why is that powered strobe lighting the camera when it should be lighting the subject. Get real. QQ.

  • Vlad Dusil

    P.S. F*** Sony for releasing this piece of s*** camera. I am outraged!

  • Ian Jackson


  • mliano


  • scatterbrained

    It’s not just “iso 25k” where this light leak occurs. I’ve seen long exposure landscape shots with clearly visible light leaks. It’s just a matter of the sun being in the right (or more aptly wrong) place in the sky relative to the camera. Since there are a lot of landscape shooters buying this camera, it makes sense that a light leak like this would be an issue. No iso 25k needed, and no LED aimed right into the camera; the sun is a hell of a lot brighter than a little flexible LED.

  • Renato Murakami

    Honest question here: Where any other cameras – mirrorless or dSLR models – subject to such scrutiny testing?
    It makes me kinda wonder if we picked other camera models, how well they’d fare out with tests like this one… shinning light directly at points where light leaking might happen.

  • battlepriest

    I can imagine any number of scenarios where you might be shooting at 25k ISO – and doing so from a location that is well lit. But that really isn’t the point. For the kind of price they are asking for this device, one would have expected the producer to have been more careful in product development.

  • battlepriest

    My Bravia and PS3 would argue with that. Best devices of their type I have ever owned.

  • battlepriest

    Of course. About 2 years ago, for example, Petapixel – and Canon – reported on a light leak issue with the Canon 5D MkIII. That issue, however, produced nothing like the kind of visible artifacts seen here – it only affected the exposure value, and did not noticeably alter the captured image, as this Sony issue does.

  • lord eels

    ill go shoot sport with my ps4

  • Tobias W.

    I’m pretty sure a properly constructed camera such as my old Olympus E-5 has no light leaks. So, here we go, I am throwing a stone…

    I wouldn’t worry so much about the light leak per se but my immediate thought is: when light can get through where it’s not supposed to, what about dust and moisture?

    This is not a cheap camera product. The fact that it shows this weakness makes me wonder about the general quality of design and manufacturing. Same goes for the Fuji X-T1.

  • ninpou_kobanashi

    It’s a F’ing CAMERA. You know, the little light tight box, where the you open the shutter to control the amount of photons let in? They can even have shutters for the eye piece so that light can’t come in from the viewfinder?

    Of course, almost every other camera manufacturer has made these kinds of mistakes, with either their bodies or their lenses. But, they should be appropriately punished when such blunders are made.

  • ninpou_kobanashi

    Replied to wrong level -> i agree with the priest!

  • hugh crawford

    I would thought that an Anti-Massacree would be that paper thing on the headrest of an airplane seat

  • bwana

    I’ve been following the Sony “leakgate” on several forums. Love the hysteria! The sky is falling! And yes, I do own a Sony A7R. I also own two Canon 60D’s and they both have the same problem if I use a light bright enough to shine through metal!!

  • Gilson Topfstedt

    good report but the finishing irritated me somehow. That`s not a matter of being a funboy or not, this problem ocurred by a top of the line camera and this issue has to be resolved by Sony, without electrical tapes and elastic hair ties. Period.