# The Light Leak Issue



## Canon Rumors Guy (Apr 8, 2012)

```
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<strong>Tested a few cameras


</strong>I went into the office today and did some tests on all the Canon DSLRs I had in stock and discovered a few things.</p>
<p>The biggest discovery I found with most of the cameras and the sunlight test is that just placing your thumb over the viewfinder isn’t enough. Bright light passes through the thumb without much issue. I discovered this when I used a folded piece of black fabric and stuffed that over the viewfinder. Most of the Canon cameras no longer had a “light leak” issue.</p>
<p>I tested with both the lens mounted with a cap on and with just the body cap on.</p>
<p>These tests were done in direct bright sunlight.</p>
<div id="attachment_9466" class="wp-caption alignnone" style="width: 585px"><a href="http://www.canonrumors.com/wp-content/uploads/2012/04/lightleak.jpg"><img class="size-medium wp-image-9466" title="lightleak" src="http://www.canonrumors.com/wp-content/uploads/2012/04/lightleak-575x431.jpg" alt="" width="575" height="431" /></a><p class="wp-caption-text">The cameras I used for testing. I even mounted the same model lens on all the bodies, the 24 f/1.4L II.</p></div>
<p><strong>Canon EOS 60D


</strong>I tested 2 bodies and found no issue once I placed the folded black fabric over the viewfinder. No change with backlight on.</p>
<p><strong>Canon EOS 7D


</strong>I tested 2 bodies and found no issue once I placed the folded black fabric over the viewfinder.  No change with backlight on.</p>
<p><strong>Canon EOS 5D Mark II


</strong>I tested the one body I have in stock. This camera exhibited the same issue as the 5D Mark III in direct sunlight, however the backlight didn’t affect exposure. I also did the flashlight test that is mentioned below and nothing changed in exposure.</p>
<p><strong>Canon EOS-1D Mark IV – Body #1


</strong>There was an ever so slight shift in exposure with the viewfinder cover down.  10 seconds out of the sun, 8 seconds in the sun. I stuffed the viewfinder with the black fabric and there was no change. The variance in exposure went away if I wrapped the LCD with the black fabric and only left enough space to see the exposure number. No change with backlight on.</p>
<p><strong>Canon EOS-1D Mark IV – Body #2


</strong>This body exhibited no movement in exposure. No change with backlight on.</p>
<p><strong>Canon EOS 5D Mark III


</strong>I only have one body to test for the moment, however it exhibits the shift in exposure  with the backlight turned on.</p>
<p>Once I placed the black fabric over the viewfinder instead of my thumb, the variance in exposure decreased in direct sunlight. However it was still present. Out of direct sunlight, the camera metered 10 seconds, in the direct sunlight the camera metered 1 second.</p>
<p>The final test I did with the 5D Mark III was take the lens cap off and meter off a relatively neutral wall. I turned on the backlight and nothing changed. I then pressed a 130 lumen flashlight up against the top LCD and the exposure didn’t change. I also ran the flashlight around the camera body and absolutely nothing changed.</p>
<p><strong>So why do things change with the caps on?


</strong>I have no idea, none, ziltch!</p>
<p><strong>So is this an issue?


</strong>On the body I tested, it doesn’t appear to be. If the camera acts properly with the lens cap off, who cares how it acts with the caps on? So please don’t return your 5D Mark IIIs, or cancel preorders or overreact. This “issue” may have a simple explanation.</p>
<p>However, if Canon says something is wrong, I apologize…… it just doesn’t appear there is an issue to me.</p>
<p><strong><span style="color: #ff0000;">c</span>r</strong></p>
```


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## Fleetie (Apr 8, 2012)

Canon Rumors said:


> I have no idea, none, ziltch!



Thanks, Craig.

Well clearly there is a very slight light leak through the LCD and also from the LCD backlight LED to the metering sensors.

But the leaked light is very little; down in the nanowatt or less range. It only shows up when there is no TTL light to swamp it.

With all caps on, and light on the LCD, you get leaked light of say 1nW (GUESS, not real!!!) on the lighting sensors. In the absence of any other light, the sensors do detect this. 

With the lens cap off, and say 1uW or likely more of TTL light hitting the metering sensors, you simply don't see the effect of the 1000 times smaller (or even smaller than that) leaked light.

I don't think the 5D3 would've made it through Beta if this had been a real issue with the lens uncapped.


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## neuroanatomist (Apr 8, 2012)

Canon Rumors said:


> ... it just doesn’t appear there is an issue to me.



Wrong. It's a HUGE issue for anyone who's favorite photographic subject is the inside of a lens cap!!!


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## spinworkxroy (Apr 8, 2012)

Thanks for the great effort. I believe not everyone would've been able to do the test you were able to..
As expected, i don't see why people are making such a big deal about that little light leak..It's like complaining about a stone in the tyre of a car you just bought…i was never bothered about this "leak" and after reading your test, i'm even less bothered about it.

BTW, that's a whole lot of 24L lenses there!


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## smirkypants (Apr 8, 2012)

I really don't get it. I really don't. Canon obviously tested the camera taking zillions of pictures in the field and they didn't notice anything that made the pictures crap.... so why the hell should I care? Even if the exposure is off 1/3 of a stop, hell, with the photos I take the exposure is NEVER exactly right. That's why we shoot RAW, isn't it?


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## diegom75 (Apr 8, 2012)

Hi guys I noticed this happens with my camera (5D mk iii), it does not happen with my original 5D. Honestly I don' see it as threat to my photography as soon as you have some light going through the lens the problem disappears and it meters accurately. I also noticed nothing records on the sensor, its just the meter that gets fooled 2/3 to 1 stop under test conditions. I'd still like to hear what canon has to say about it.


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## altenae (Apr 8, 2012)

Thanks for testing.


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## nikkito (Apr 8, 2012)

maybe it's just a LOMO effect  ;D


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## TrumpetPower! (Apr 8, 2012)

So, just to make sure I've got this right:

The next time I'm photographing a black cat at the bottom of an unlit coal mine, if I want to use the camera's meter, I should make sure I don't also use the LCD backlight at the same time, or let any stray sunlight strike it either?

I think I can live with that....

b&


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## NaturaLight (Apr 8, 2012)

I was going to say what Fleetie said. He's right, and your tests indicate that. (So the new plan is to accept the camera when it arrives...)


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## msdarkroom (Apr 8, 2012)

Perhaps the reason that this shows up with the cap on is because the sensor is actually really really sensitive, more so than on older models, and that is why it seems to show up on the high end gear only.
IE: The same minor leaks as on all gear, but now the sensor can see it.

Boom.


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## april (Apr 8, 2012)

i believe this movement in exposure with the lenscap on is not triggered by a light leak. its the same as when pressing the shutter button in total darkness wherein the camera is trying to meter the available light for it to set the exposure, with the lens on this shall go with the hunting of the lens for focus. in this situation the camera metering is fooled and couldn't lock the focus and exposure therefor the shutter will not trigger unless you overide the cameras' computer by going to manual mode.


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## justsomedude (Apr 8, 2012)

neuroanatomist said:


> Canon Rumors said:
> 
> 
> > ... it just doesn’t appear there is an issue to me.
> ...



All sarcasm aside... does anyone not see how this could be a serious issue for astrophotographers? 

If you are using a headlamp or the LCD backlight to set your exposure for a night sky capture, you could be in serious trouble. I'll be doing some tests tonight and will follow-up tomorrow.

I fear the 5D3 may not be suited for astrophotography at all if this problem affects nighttime exposures.


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## TrumpetPower! (Apr 8, 2012)

msdarkroom said:


> Perhaps the reason that this shows up with the cap on is because the sensor is actually really really sensitive, more so than on older models, and that is why it seems to show up on the high end gear only.
> IE: The same minor leaks as on all gear, but now the sensor can see it.
> 
> Boom.



Actually, if anybody here is handy with math, it might be possible to do a calculation to see if that reasonable-sounding theory holds up.

What is the actual increase in illumination indicated by the change in meter readings, and how does that compare with the actual light levels at the (new) bottom of the 5DIII's sensitivity? If there's any overlap...

...though that still would only be of idle curiosity to the non-lenscap non-black-cat-in-coal-mine crowd....

b&


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## javier (Apr 8, 2012)

Hi,

I test it and yes that happes to mine too but............

here is my real problem:

If I take a picture for example: Manual 4.0 / 1/200 / iso 800 & I compare the same but in P mode the manual picture is a bit darker like 2/3 also you can notice that if you check the histogram.

since I start to take picture with my 5d mark iii I notice the picture was a bit dark like 2/3 so if I want to take the picture right I have to set my meter to +2/3

anyone with this problem?


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## TrumpetPower! (Apr 8, 2012)

justsomedude said:


> neuroanatomist said:
> 
> 
> > Canon Rumors said:
> ...



I've not done any astrophotography, but I was under the impression that the onboard meter is perfectly useless for such work. Or any meter, for that matter -- I thought the serious stuff was all done either from well-established exposure charts or by stacking multiple exposures....

b&


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## cinema-dslr (Apr 8, 2012)

could it be that they switched the amber backlight position from the right(7d) to the left next to the mirorbox?

when you look at the lcd at an angle you can make out the led.
i believe that one side of the lcd is mirrored off to reflect the backlight back.
the ledside isn't so sunlight can sliptrough and the ledlight itself will have a more profound effect when placed next to the mirror box

can someone check the position of the backlight led on the markIII?


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## Tov (Apr 8, 2012)

msdarkroom said:


> Perhaps the reason that this shows up with the cap on is because the sensor is actually really really sensitive, more so than on older models, and that is why it seems to show up on the high end gear only.
> IE: The same minor leaks as on all gear, but now the sensor can see it.
> 
> Boom.



Good one.
Already people are seeing more vignetting on there lenses, probably also due to the sensor.
I still have old stuff, lucky me.

very juicy picture btw.


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## Fleetie (Apr 8, 2012)

justsomedude said:


> neuroanatomist said:
> 
> 
> > Canon Rumors said:
> ...



Erm, no.

Because you would NOT rely on the camera's idea of what is correct exposure when doing astrophotography. Because if you did, the camera would seek to make the picture's lightness similar to that for normal photography.

You simply don't use the camera's exposure system when photographing star fields, because the overwhelming majority of the field is near-black.

You go to manual, or bulb.

Unless you're doing high-magnification photos of the Moon or other frame-filling objects, in which case you're now doing daylight photography, and basically, the terrestrial sunlit "Sunny f/16" rule applies.

Also, you're unlikely to be using headlights or bright torches anyway when engaged in astrophotography, because doing so would destroy your night vision.

BUT, please do report back your findings, because it will be a useful data point.

The 5D3 is the most light-sensitive/noise-free DSLR that exists in a conventional-size (non-integrated-grip) body at the present time, AFAIK. 

So it would seem, it's the best such DSLR for astrophotography. (Possibly barring the 60DA, but even then I suspect the 5d3 wins on low-light performance.)


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## altenae (Apr 8, 2012)

> Already people are seeing more vignetting on there lenses, probably also due to the sensor.



?
Maybe because they switched to a Full Frame !
Same vignetting on my 5D mark iii as on the 1ds/5d mark ii.


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## Tov (Apr 8, 2012)

altenae said:


> > Already people are seeing more vignetting on there lenses, probably also due to the sensor.
> 
> 
> 
> ...



I was trying to be sarcastic.


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## altenae (Apr 8, 2012)

Read this elsewhere.

Read it and think about it.
This leak thing with cap on is BS.


These lens cap on tests are ludicrous beyond belief. 
They involve light levels far beyond the meter's range of operation. The meter is designed to produce an image that is 18% grey. Does anyone seriously think that the meter reading in these tests, with or without the LCD light, are registering 18% grey.

Add to that the fact that the EV scale is non-linear and it's hard to see how a rational, informed person could get so hysterical about this. The quantity of light required to shift exposure by 1 stop at these levels becomes a tiny fraction of a stop at real exposure levels - probably less light than leaks into the viewfinder past your eye - and much much less if you happen to look through the viewfinder wearing glasses.


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## altenae (Apr 8, 2012)

Tov said:


> altenae said:
> 
> 
> > > Already people are seeing more vignetting on there lenses, probably also due to the sensor.
> ...


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## JR (Apr 8, 2012)

Thanks for all the test Graig. I would assume Canon would get back to you with their official story on this issue? Or have you shared with them at all? Curious...


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## Mt Spokane Photography (Apr 8, 2012)

justsomedude said:


> neuroanatomist said:
> 
> 
> > Canon Rumors said:
> ...


 
If you turn a bright light on during a long exposure, you will have 10,000 more times light leaking thru the lens than the lcd. Set your exposure before opening the shutter, in fact, I don't believe you can set a different exposure once the shutter is open. Try that and let us know how it works.

BTW, last evening, I had tried some of the same tests that Craig did and found the same results. It is very difficult to block all light from entering the viewfinder, holding it to your eye lets enough light in to change the exposure slightly as you move from shadows to direct sunlight. However, even with a very bright led flashlight, and even the bright sun on the top LCD, I could not cause a change in exposure when the viewfinder was totally blocked.

I seem to recall someone doing the same test on the 5D MK II 4 years ago, it had no effect on mine the past 4 years, and does not affect exposures on my 5D MK III.


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## NormanBates (Apr 8, 2012)

so is the light leak "only to the light meter" or "to the sensor too"?
because I can live happily with the former, but the later would be a killer (I like stars timelapses)


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## bp (Apr 8, 2012)

Thanks for testing so thoroughly Craig. Basically the same results I found when trying to "leak" into an actual lens-cap-off exposure. I just can't force myself to get concerned over P-mode shots of the back of the lens, because I only do that when I'm REALLY drunk


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## bp (Apr 8, 2012)

msdarkroom said:


> Perhaps the reason that this shows up with the cap on is because the sensor is actually really really sensitive, more so than on older models, and that is why it seems to show up on the high end gear only.
> IE: The same minor leaks as on all gear, but now the sensor can see it.
> 
> Boom.



Actually... this is probably the best explanation I've heard so far. The 5D3 does seem to be MUCH more sensitive to dark situations than any other body I've ever had the pleasure of trying. I'd be very curious to see if the 1DX also does the same thing in idiotic lens-cap-on tests.


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## Stephen Melvin (Apr 8, 2012)

justsomedude said:


> All sarcasm aside... does anyone not see how this could be a serious issue for astrophotographers?
> 
> If you are using a headlamp or the LCD backlight to set your exposure for a night sky capture, you could be in serious trouble. I'll be doing some tests tonight and will follow-up tomorrow.
> 
> I fear the 5D3 may not be suited for astrophotography at all if this problem affects nighttime exposures.




The only thing this appears to affect is the meter; it doesn't affect the exposure at all. I just don't see how this is going to be of any relevance. Do you really meter the night sky? Or do you take a test shot and see what it looks like? For that matter, with experience, I'd expect the exposure to be known and consistent.


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## Mt Spokane Photography (Apr 8, 2012)

bp said:


> msdarkroom said:
> 
> 
> > Perhaps the reason that this shows up with the cap on is because the sensor is actually really really sensitive, more so than on older models, and that is why it seems to show up on the high end gear only.
> ...


 
The image sensor has nothing to do with the metering settings on the display. The metering sensor is under the mirror and is used to set aperture and shutter speed. This means light is getting to the metering sensor. Obviously, if it gets to the metering sensor, then it probably gets to the main sensor as well, its just not very much light.


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## bormo (Apr 8, 2012)

Ok, just made test on my 5dIII, have leak,

one more test 
- close both caps (viewfinder and lens)
- set max iso
- set 30"
- make shot with backlight and without
- check difference (I have minor one, kind of 2 vertical lines)

On iso 6400 no difference


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## Lstop-photo (Apr 8, 2012)

I have also notice a2/3rd of a stop difference on the 5D3. When I received the new camera I tested the exposure against gray targets, just to see how the new metering system was faring. I have noticed the same difference in my everyday shooting, and have set the cam at +2/3 pretty much consistently. 

I don't know if this is related to the light leaked issue or simply the way the new metering system behaves, but I would be interested in knowing if other people have noticed.

Luc


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## javier (Apr 8, 2012)

Lstop-photo said:


> I have also notice a2/3rd of a stop difference on the 5D3. When I received the new camera I tested the exposure against gray targets, just to see how the new metering system was faring. I have noticed the same difference in my everyday shooting, and have set the cam at +2/3 pretty much consistently.
> 
> I don't know if this is related to the light leaked issue or simply the way the new metering system behaves, but I would be interested in knowing if other people have noticed.
> 
> Luc





Ok thanks I now know I am not crazy and this actually happens.

If I take a picture for example: Manual 4.0 / 1/200 / iso 800 & I compare the same but in P mode the manual picture is a bit darker like 2/3 also you can notice that if you check the histogram.

since I start to take pictures with my 5d mark iii I notice the picture was a bit dark like 2/3 so if I want to take the picture right I have to set my meter to +2/3


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## altenae (Apr 8, 2012)

javier said:


> Lstop-photo said:
> 
> 
> > I have also notice a2/3rd of a stop difference on the 5D3. When I received the new camera I tested the exposure against gray targets, just to see how the new metering system was faring. I have noticed the same difference in my everyday shooting, and have set the cam at +2/3 pretty much consistently.
> ...



First do the test with the lenscap off. 
With me and others including the test of CR no issue at all. 
The metering is not responding to any light at all. 

Test this first before you think there is a real problem with the 5d mark iii


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## justsomedude (Apr 8, 2012)

TrumpetPower! said:


> justsomedude said:
> 
> 
> > neuroanatomist said:
> ...



Maybe I've been taught the wrong way, but I've regularly used the camera's metering system for astrophotography. By ramping up to a high ISO (say 3200), and performing a short exposure, you can then calculate back out to an equivalent exposure at 100 ISO using a bulb. But if your initial "base" (for calculating) exposure is wrong, your 3-hour equivalent will be shot, and no one likes to waste three hours under a night sky.

Granted, most astrophotographers will thoroughly check the LCD and histograms before moving forward with a longer exposure - it just sucks knowing that the initial calc made off the LCD display may be totally bogus.

This isn't really a deal breaker - since most longer exposures are done manually - it just means the LCD could be useless for performing one's exposure calcs. Kinda crummy, especially since that LCD backlight is invaluable in the hills when its pitch black. Looks like I'll just have to use the LCD preview and INFO screen instead, once the test exposure is complete.

Meh.


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## altenae (Apr 8, 2012)

Read this on FM and I think he is 100% right. 

this finding of a purported light leak on the 5D3, is typical of this stage of the life of a new camera model, in a world where too many buyers of such stuff are nerds rather than photographers (I confess being a nerd myself):

someone sets the camera up in a weird way, ie blocking any light from entering
this someone apparently doesn't realise that this means any further "experimenting" will be basically measuring noise. 

But doing so in ways much less useful or professional than the manufacturer would
the same person then proceeds to flash a light at the camera. Woooo, apparently a tiny bit of that light gets in!

Should one therefore panic?

Yes if the person regularly (1) shoots in very very very very low light, and (2) regularly flashes strong lights at their camera while shooting in these conditions.

WHO does this? NO ONE. Astrophotographers DO shoot in very very very low light (not THAT low - nowadays any decent DSLR can capture say Orion, hand-held). 
But they do NOT flash lights at the camera while shooting.
Camera makers are of course happy with any additional sale made - but frankly one sometimes wishes there were more photographers out there, and less failed testers / nerds. Puh-lease!


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## javier (Apr 8, 2012)

altenae said:


> javier said:
> 
> 
> > Lstop-photo said:
> ...




I am talking when I take pictures normally


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## epsiloneri (Apr 8, 2012)

justsomedude said:


> Maybe I've been taught the wrong way, but I've regularly used the camera's metering system for astrophotography. By ramping up to a high ISO (say 3200), and performing a short exposure, you can then calculate back out to an equivalent exposure at 100 ISO using a bulb. But if your initial "base" (for calculating) exposure is wrong, your 3-hour equivalent will be shot, and no one likes to waste three hours under a night sky.


It sounds like a good way, but from what you describe it seems you are using the test exposures to compute the longer exposure time, not the camera metering system. Thus you would not be affected by this "light leak".

It's funny how when the 60Da was surprisingly released last week, people were complaining about the _lack_ of Canon leaks. There is really no way to please everyone :


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## altenae (Apr 8, 2012)

javier said:


> altenae said:
> 
> 
> > javier said:
> ...



Yes I understand, but don't blame your issues which this leaking light with lenscap on.


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## neuroanatomist (Apr 8, 2012)

Mt Spokane Photography said:


> The metering sensor is under the mirror and is used to set aperture and shutter speed. This means light is getting to the metering sensor. Obviously, if it gets to the metering sensor, then it probably gets to the main sensor as well, its just not very much light.



The metering sensor was under the mirror in old designs, but these days it's actually up in the pentaprism housing (labeled in the upper right of this diagram taken from a Canon tech report):







So, light that reaches the metering sensor should be blocked from hitting the image sensor by the mirror when it's flipped up during the exposure.


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## prestonpalmer (Apr 8, 2012)

I am glad you recognized that light leaks through thumbs! Good catch. Since my 5D2 acts the same way, im gonna say NO ISSUE here! 

Now, back to wedding photography.


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## javier (Apr 8, 2012)

prestonpalmer said:


> I am glad you recognized that light leaks through thumbs! Good catch. Since my 5D2 acts the same way, im gonna say NO ISSUE here!
> 
> Now, back to wedding photography.



What about the 2/3 stop off in normal use of the camera.


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## altenae (Apr 8, 2012)

javier said:


> prestonpalmer said:
> 
> 
> > I am glad you recognized that light leaks through thumbs! Good catch. Since my 5D2 acts the same way, im gonna say NO ISSUE here!
> ...



Javier, If you think it is the camera, return it. 
My friend and I do NOT have 2/3 stop off in normal use.


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## Rob Wiebe (Apr 8, 2012)

Hmmm only affects my 5D3 without a lens and thumb instead of cover too. No issue with lens on or rubber cover on eyepiece .... LOL"


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## altenae (Apr 8, 2012)

Rob Wiebe said:


> Hmmm only affects my 5D3 without a lens and thumb instead of cover too. No issue with lens on or rubber cover on eyepiece .... LOL"




It sounds like this effect is only observed when there is so little light that the sensor is blindly guessing at the exposure. What is the "correct" exposure that the camera should be reporting when the camera has the lens cap on and viewfinder closed?

So it just could be the exposure readings with cap on and VF covered are NOT correct at all. 
So how do we know what the impact is when the LCD light is on ?

Anyway NO issue without the lenscap at all


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## Mt Spokane Photography (Apr 8, 2012)

neuroanatomist said:


> Mt Spokane Photography said:
> 
> 
> > The metering sensor is under the mirror and is used to set aperture and shutter speed. This means light is getting to the metering sensor. Obviously, if it gets to the metering sensor, then it probably gets to the main sensor as well, its just not very much light.
> ...


 
+1

OOPS, its the AF sensor down there. I knew that, just getting too old.


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## zim (Apr 8, 2012)

Mt Spokane Photography said:


> neuroanatomist said:
> 
> 
> > Mt Spokane Photography said:
> ...



Had a couple of noggins tonight guys so maybe not thinking to straight but what then does that piece of rubber crap that goes over the eye piece do for things thats attached to the camera strap?


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## DavidRiesenberg (Apr 8, 2012)

It is meant to prevent light from entering through the viewfinder when you're shooting on a tripod. And using it is a must if you don't have time or want to tweak the exposure manually.


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## zim (Apr 8, 2012)

So why did they remove this especially from 'pro' cameras?


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## Stephen Melvin (Apr 8, 2012)

zim said:


> So why did they remove this especially from 'pro' cameras?



You see that little lever? It activates the internal shutter blind, so we don't need to carry around that little rubber piece of junk.

On the other hand, that eyepiece blind is a frequent point of failure in Nikons.


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## HughHowey (Apr 9, 2012)

Stephen Melvin said:


> zim said:
> 
> 
> > So why did they remove this especially from 'pro' cameras?
> ...



Really? I've always wondered why Canon didn't include that feature. Always thought it was nifty.


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## AUGS (Apr 9, 2012)

neuroanatomist said:


> Mt Spokane Photography said:
> 
> 
> > The metering sensor is under the mirror and is used to set aperture and shutter speed. This means light is getting to the metering sensor. Obviously, if it gets to the metering sensor, then it probably gets to the main sensor as well, its just not very much light.
> ...


100% confirmed - for my 5D3. I have done these crazy tests and most importantly - every frame I exposed (using manual focus) came out completely black. Therefore, no stray light from the “metering leakage” is getting to the sensor. I even did a 120 second bulb exposure with direct sunlight onto the LCD panel at ISO800 and only the slightest stray light was witnessed and that was found to come through the VF cover – so it isn’t perfect either. When I removed this tiny VF leak, a 256 second bulb exposure got absolutely nothing. To put in context, a proper exposure was 1/1000 second at f/8.


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## spinworkxroy (Apr 9, 2012)

Oh no..
i think we have a bigger design flaw here than just the 5D3 light leak..
After all the tests done, i think the biggest flaw is….OUR thumbs leak light!!!
So all those years of covering someone's eyes with our hands proved to be useless!! They can still see with light leaking through!!! Oh no…wonder if we will be recalled.


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## D.Sim (Apr 9, 2012)

HughHowey said:


> Stephen Melvin said:
> 
> 
> > zim said:
> ...



I await the day that Canon releases an eyepiece extender with a little lever for us to close a shutter within the extender for the same effect....


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## skitron (Apr 9, 2012)

spinworkxroy said:


> Oh no..
> i think we have a bigger design flaw here than just the 5D3 light leak..
> After all the tests done, i think the biggest flaw is….OUR thumbs leak light!!!



Dang good thing they do! Otherwise those thingies they put on your thumb or finger at the hospital to check your O2 level wouldn't work so hot. 

Moral to the story: thumb - good for O2 testing, not so much for keeping light out of the viewfinder! ;D


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## highnfar (Apr 9, 2012)

have you done tests like this in the video below? 

http://youtu.be/oF8CW723wEo


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## nickzh (Apr 9, 2012)

I just did a similar test, taking two outdoor pictures with my new 5D MK iii. The one without the lcd light on is metered for 10" exposure duration and turns out fine. When I use the lcd backlight the meter shows 6" exposure duration and the shot gets underexposed by almost one 1 stop.
I acknowledge these tripod mounted night shots with long exposure duration are not the ones I do regularly, but to me the light leak problem seems very real. 
So, should I send the camera back?


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## Kernuak (Apr 9, 2012)

nickzh said:


> I just did a similar test, taking two outdoor pictures with my new 5D MK iii. The one without the lcd light on is metered for 10" exposure duration and turns out fine. When I use the lcd backlight the meter shows 6" exposure duration and the shot gets underexposed by almost one 1 stop.
> I acknowledge these tripod mounted night shots with long exposure duration are not the ones I do regularly, but to me the light leak problem seems very real.
> So, should I send the camera back?


Is it normal practice (for you or anyone else for that matter) to have the LCD backlight on when metering? If your answer is no, then just use it as you normally would and don't waste your time and potentially money returning it. If yes, then may be you need to review your practices and/or make manual adjustments.


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## mrmarks (Apr 9, 2012)

If anything is used outside of its intended function, it will probably result in some unintended or unusual outcome. For example, if the reverse gear is used to try stop a car, this will result in a less than desirable driving experience. In one of the tests done by a user, a long exposure was taken at night on a tripod and when the LCD light was turned on, the exposure time decreased. Perhaps, the LCD display needed to be lighted up to check the settings, but after it turns off automatically in a few seconds, then an exposure can be taken. There is no need for the LCD to be lighted up when an exposure is taken. For long exposures, it is common practise to cover the camera body with a light-proof black cloth to prevent stray light from entering the VF and causing flaring effects in the exposure. I doubt Canon will do anything about this "issue" and at the most Canon will just send out an application note?


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## neuroanatomist (Apr 9, 2012)

mrmarks said:


> Perhaps, the LCD display needed to be lighted up to check the settings, but after it turns off automatically in a few seconds, then an exposure can be taken. There is no need for the LCD to be lighted up when an exposure is taken.



But what if you wanted to repeatedly verify your settings _during_ the exposure by viewing the LCD during the exposure?!? Don't go saying that's not realistic because you can't change the settings at that point or that pressing a button on the camera would result in a blurry image. It's more realisitc than taking pictures with no lens...


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## mrmarks (Apr 9, 2012)

neuroanatomist said:


> mrmarks said:
> 
> 
> > Perhaps, the LCD display needed to be lighted up to check the settings, but after it turns off automatically in a few seconds, then an exposure can be taken. There is no need for the LCD to be lighted up when an exposure is taken.
> ...



LOL! Actually I don't even use the top LCD as I check all my settings in the rear LCD in quick mode all the time. I can't be bothered even if the top LCD is removed.


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## smirkypants (Apr 9, 2012)

mrmarks said:


> LOL! Actually I don't even use the top LCD as I check all my settings in the rear LCD in quick mode all the time. I can't be bothered even if the top LCD is removed.


+1 ... I seriously wouldn't notice if the LCD were gone.


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## mrmarks (Apr 9, 2012)

Canon EOS 60D
I tested 2 bodies and found no issue once I placed the folded black fabric over the viewfinder. No change with backlight on.

Canon EOS 7D
I tested 2 bodies and found no issue once I placed the folded black fabric over the viewfinder. No change with backlight on.

Canon EOS 5D Mark II
I tested the one body I have in stock. This camera exhibited the same issue as the 5D Mark III in direct sunlight, however the backlight didn’t affect exposure. I also did the flashlight test that is mentioned below and nothing changed in exposure.

Canon EOS-1D Mark IV – Body #1
There was an ever so slight shift in exposure with the viewfinder cover down. 10 seconds out of the sun, 8 seconds in the sun. I stuffed the viewfinder with the black fabric and there was no change. The variance in exposure went away if I wrapped the LCD with the black fabric and only left enough space to see the exposure number. No change with backlight on.

Canon EOS-1D Mark IV – Body #2
This body exhibited no movement in exposure. No change with backlight on.

-----------------------------------------------------

Could someone check which side is the LED (inside the LCD) on all the tested bodies? In the 5D3, the LED is on the left side, closer to the metering sensor. Could it be that all the other bodies have the LED on the right side? Just a hyphothesis. You could check the LED position by looking sideways into the LCD.


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## justsomedude (Apr 9, 2012)

Kernuak said:


> nickzh said:
> 
> 
> > I just did a similar test, taking two outdoor pictures with my new 5D MK iii. The one without the lcd light on is metered for 10" exposure duration and turns out fine. When I use the lcd backlight the meter shows 6" exposure duration and the shot gets underexposed by almost one 1 stop.
> ...



As I noted previously - some astrophotographers use the LCD backlight during metering to observe the exposure settings. Well - at least I do. This way I can use the settings to calculate a longer exposure for a manual/bulb exposure. And there's really no way to see that LCD display without activating the backlight (or by using a headlamp - which we're learning can also effect the metering).

So if we can't use the backlight under pitch black conditions out in the field - then one could certainly resort to the rear LCD image preview/info screen. However, this is a huge hindrance in my opinion. If the camera is on a tripod in a funky position, where access to the rear LCD is totally obstructed, you would literally be screwed. 

I don't think everyone is realizing how much of a serious problem this is turning out to be (at least for nighttime landscape photographers).


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## justsomedude (Apr 9, 2012)

From the video previously posted by "highnfar," here are screen caps of images taken with the backlight on during metering, and backlight off during metering....


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## cinema-dslr (Apr 9, 2012)

mrmarks said:


> Canon EOS 60D
> I tested 2 bodies and found no issue once I placed the folded black fabric over the viewfinder. No change with backlight on.
> 
> Canon EOS 7D
> ...



that was what i was suggesting. on my 7d the amber backlightled is on the right side.
So it seems they made a placement error.
It may be a small to nonexistent problem but still should be easy to fix for canon.


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## JLJL (Apr 10, 2012)

Serious Light Leak Issue with the 5D mark III!

Light leaking trough top LCD causes underexposure. This is true for the for other sources, e.g. sunlight!

http://www.akphotodenver.com/images/backlight.jpg

D81 0512

http://translate.google.com/translate?sl=nl&tl=en&js=n&prev=_t&hl=nl&ie=UTF-8&layout=2&eotf=1&u=http://nl.fotovideo.nu/nieuws/27104/test-5d-mark-iii-light-leak-bug


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## epsiloneri (Apr 10, 2012)

justsomedude said:


> I don't think everyone is realizing how much of a serious problem this is turning out to be (at least for nighttime landscape photographers).



I don't think it is. Please see my earlier reply to you (#38).


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## AUGS (Apr 10, 2012)

justsomedude said:


> From the video previously posted by "highnfar," here are screen caps of images taken with the backlight on during metering, and backlight off during metering....



Yes, I agree I can see a visible difference between the images. But which image is the correct exposure for the scene and what you are trying to achieve? Without a review of the histograms and images, neither may be correct, and for night photography nor should they be assumed to be correct. (FWIW, the image on the right looks over-exposed, but its almost impossible to tell from such a small grab - and I do know the left is the LCD affected exposure.)
I'm not saying there isn't a problem, there clearly is but it looks to be manageable. In my experimentation, I've found that the only time the exposure is affected is when the LCD panel in is brighter light than the image to be captured and how much it is affected depends on the intensity difference.
With this knowledge in hand we are forewarned and hence forearmed and can work around it - albeit we shouldn't and I wish we didn't have to, but it is what it is at the moment. 
My workflow for night photography will not change:
1. Compose the image and set focus.
2. Set a high ISO, Aperture Priority, biggest aperture for the lens, set autobracket +/-1 stop.
3. Review the 3 histograms and images.
4. Switch to Manual mode, with same ISO, same aperture, and adjusted time based on review of previous images and the result I want to achieve.
5. Confirm adjusted exposure by creating another image or adjust again. Determine Bulb exposure time for desired ISO and desired aperture.
6. Set bulb setting, start exposure, grab a coffee, plug in the iPod and wait.

The good news is I've confirmed (on my 5D3 at least) that the light leakage does not get to the image sensor when the mirror is up, so the activation of the LCD or the use of a head-torch or similar during the exposure doesn't affect the image.


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## bp (Apr 10, 2012)

People are still screaming about this? Seriously? Yes yes, this is a HUGE PROBLEM!!!!!!!!!!!!
IF you're doing near pitch-black landscape photography
AND you're relying on the meter to figure out your exposure for you
AND you've put the camera in a place where you can't use the rear LCD
AND you're not willing to wait to execute the exposure until after the LCD backlight turns off 

I don't do much nighttime landscape / astrophotography - but when I have, I've never once relied on the camera's metering system. That's what M mode and a few test shots are for. Why all the drama?


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## Martin (Apr 11, 2012)

Please could you check metering in normal use? I had very annoying problem with 5D2 which underexposed by 2/3 stop all the time. I did a white(gray) wall test with all different mattering modes and histogram against white or gray card was off to the left by 2/3 stop. it's not normal behaviour as it should be set dor 18% gray, so the histogram peak should be perfectly in center. Please check if 5d3 is also affected by this issue.


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## kozakm (Apr 11, 2012)

FYI: 1D X is ok, no light leak problem (tested)


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## javier (Apr 14, 2012)

altenae said:


> javier said:
> 
> 
> > prestonpalmer said:
> ...



I told you.... http://www.usa.canon.com/cusa/registration/professional/professional_cameras/digital_slr_cameras/eos_5d_mark_iii

Also another guy find the camera is getting to much light through the view finder, so my conclusion is...
Canon 5D Mark III - Light Leak via Viewfinder

the sensor is getting to much light "leaks" and when you take the picture the picture just use the light coming through the lens and that is why the pictures are underexposed.


so start to pack your camera for a replacement, I already sent mine for a refund 3 days ago, and now I am waiting to see how this ends to buy a new version.


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## ramon123 (Apr 14, 2012)

*Are the new 5D Mark III's being recalled?*

Are the new 5D Mark III's being recalled, meaning are they asking for everyone to bring back their newly bought units and either get a refund or credit for the fixed model in a few months?


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## te4o (Apr 14, 2012)

*Re: Are the new 5D Mark III's being recalled?*

As often this forum is far too quick: there seem to be thousands of us doing every new hard/software test immediately and spreading the info minutes later: I find this is great! 
A company cannot compete with this speed especially if it is making non-vitally relevant products (no life danger from a light leak there). I expect weeks and months until we know if the cameras will be recalled and what will be done to them and where. 

My 5D3 arrived on Friday and no one has phoned me over the weekend to let me know Canon needs it back on Monday. And, yes it has the light leak issue as my old 40D without me noticing.


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## revup67 (Apr 14, 2012)

*Re: Are the new 5D Mark III's being recalled?*

te4o - not sure if you saw this but just an FYI



> Please register the EOS 5D Mark III. By registering, we will be able to notify you via email when service updates are available. If you already registered, please ensure you are opted-in to receive the notification.



http://www.usa.canon.com/cusa/registration/professional/professional_cameras/digital_slr_cameras/eos_5d_mark_iii


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## JR (Apr 15, 2012)

*Re: Are the new 5D Mark III's being recalled?*

Not sure they determined the action to take yet. Bets is to register like someone else mentionned.


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## prestonpalmer (Apr 15, 2012)

*Re: Are the new 5D Mark III's being recalled?*



JR said:


> Not sure they determined the action to take yet. Bets is to register like someone else mentionned.



Yep, register and wait. I am curious to see what they say officially. Its funny because my 5D2 does the EXACT SAME THING.


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## mrmarks (Apr 15, 2012)

*Re: Are the new 5D Mark III's being recalled?*



prestonpalmer said:


> Yep, register and wait. I am curious to see what they say officially. Its funny because my 5D2 does the EXACT SAME THING.



I did not have the chance to test on my 5D2 as it was just sold off. But I was using it for years with great results. Was the LED lights inside the top LCD on the left side or right side in the 5D2 (with the lens facing away from you)? It would have made sense for the LED lights placed further away from the metering sensor.


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## Viggo (Apr 15, 2012)

I tried register, but it's not for europe, sorry if this has been answered, but how do we in europe register our 5d3's?


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## te4o (Apr 15, 2012)

*Re: Are the new 5D Mark III's being recalled?*



revup67 said:


> te4o - not sure if you saw this but just an FYI
> 
> 
> 
> ...



Thanks revup, I noticed that but I can't register with Canon USA as I live and shoot in Australia. Just trying to figure out whether Canon Australia has light leak knowledge too.


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## highnfar (Apr 16, 2012)

*Re: Are the new 5D Mark III's being recalled?*

better to contact canon australia, told them canon us announced this problem and ask them for solution. more people request, faster they respond.



te4o said:


> revup67 said:
> 
> 
> > te4o - not sure if you saw this but just an FYI
> ...


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