Canon CCD Exposure Sensors

Accurate metering is very important for comfortable work with modern SLR cameras. exposure.

Metering Sensor Locations

Measurement Sensor Locations exposure in the camera Canon EOS 7D Digital

On digital SLR cameras froze exposurewhen sighting through JVI, is produced using a special sensor located behind the pentaprism or pentamirror of the camera. Metering is performed with a fully open aperture for reflected light (so called 'Full Aperture TTL metering'). When using Live View, metering exposure produced using the main matrix of the camera, which, at times, allows you to determine it more accurately :).

Metering sensor
Camera models
21-zone SPC
35-zone SPC
63-zone SPC
63-zone dual layer SPC and iFCL
63-zone (9 * 7) with 7560-pixel RGB with IR support
252-zone with 150.000-pixel RGB AE sensor supporting IR, iTR and iSA
252-zone with 100.000-pixel RGB AE sensor with iTR and iSA support
63 zone (18 * 12) with 7.560-pixel RGB with IR support
Zone module with 360,000-pixel RGB AE sensor supporting IR, iTR and iSA
Zone module with 220,000-pixel RGB AE sensor with iTR support and assistive AF

Measuring sensors exposure Canon EOS Digital cameras are a kind of main matrix, divided into a certain number of zones or pixels that capture the light flux. Each zone is responsible for a part of the frame and measures only for the selected area. As it turned out, many cameras use the same sensor, and the differences in the operation of exposure metering concern only data processing algorithms, as well as various subtleties of pairing the exposure metering system with the focusing system.

63 zone meter with dual layer SPC

63 zone meter with dual layer SPC

Basically, all measurement sensors are built on a silicon basis and are called SPC (Silicon Photo Cell is a silicon photocell). Before the advent of the dual-layer SPC sensor in the Canon 7D, one could say that Canon cameras measure from a monochrome image, without distinguishing colors... Such sensors can make errors due to different sensitivity to the spectrum components, for example, they are more sensitive to red color, which, in certain situations, can lead to measurement errors. exposure. To combat this effect, an additional filter is placed in front of the sensor, which makes the SPC sensor neutral to different components of the spectrum.

Spoiler: TsKK Nikon from time immemorial for measurement exposure use full-color CCD-type RGB sensors and do not know grief :)

Canon 7D uses a system to improve the performance of the exposure metering system iFCL (Intelligent Focus Ccolor, Luminance) based on a two-layer SPC sensor. After the release of the Canon 7D, this system began to be installed on amateur cameras, a list of them can be seen in the plate above (models with '63 zone with dual layer SPC and iFCL ').

Two-layer SPC

Two-layer SPC (The basis of the figure for the diagram is taken at

One SPC layer is sensitive to red and green components, the second to blue and green. During operation, the microprocessor compares the signal levels from both layers and calculates the required exposure parameters.

Also, a new system iFCL uses focus to determine the correct exposure (Focus), color (Color) and brightness (Luminance) image. Focus points determine the distance to the subject, with the help of which special algorithms help to calculate the most correct exposure (that is, not only by image brightness and color). Roughly speaking, the focus points allow you to select the subject in the picture, and, accordingly, the priority area for metering exposure. In different cameras, pairing with focus points has its own characteristics and operation algorithms.

A similar mode is available in cameras using a conventional 63-zone sensor - 1D Mark IV, 1D Mark III, 1Ds Mark III. These cameras also have focus points and exposure metering paired. The key difference from the dual layer SPC sensor is the lack of multiple layers that are sensitive to different colors. In cameras using 21 or 35 zone sensors, things are a little worse.

Exposure sensor view for canon 1dx camera

Exposure sensor view for canon 1dx camera

A more accurate and sophisticated metering sensor has been developed for the Canon EOS 1D X and Canon EOS 1D C cameras, which already measures by color image and has a huge number of possibilities (the so-called technology iTR - Intelligent Tracking and Recognition - tracking and recognition system paired with technology iSA - Intelligent Subject Analysis - intelligent analysis of objects). Here are its basic features:

  • determines the presence of a person in the frame
  • calculates color distribution information in a frame
  • helps to more accurately determine the location of the subject when using the auxiliary flash (strobe)
  • in low light conditions, 252 zones are combined into 35 larger zones, which allows more accurate measurement
  • together with the focusing system allows you to implement color-tracking
  • Sensor algorithms relate differently to each color, allowing for more flexible exposure control

Most likely we will see this 252-zone RGB sensor in many subsequent Canon models.

The 7D Mark II uses a Canon EOS 1D X-like meter, however, the number of pixels in it has been increased to 150.000. In addition, the 7D Mark II for metering takes into account infrared spectrum (IR), which allows you to more accurately determine the exposure of the image. And a unique feature appeared when shooting scenes with flickering light, which allows you to take a picture only at maximum brightness.

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Material prepared Arkady Shapoval. Training/Consultations | Youtube | Facebook | Instagram | Twitter | Telegram

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Comments: 47, on the subject: Canon CLC exposure sensors

  • Dmitry K

    all the same, what an advanced 7D camera was)) and video, and autofocus, and a matrix ... now it turns out that exposure metering is also new and the most advanced .. the rest of the cameras can say "caught up" with the seven only recently

    • Dima

      Nikanists will remember the clumsy d7000)

  • Oleg

    But in mirrorless cameras, in contrast to DSLRs, the exposure is measured not by separate remote sensors, but directly by the entire area of ​​the matrix - therefore, the exposure metering in system cameras is more perfect

    • Do_Oraemon

      And yet there are enough minuses in mirrorless cameras. This is a constantly open matrix, and a slower autofocus, and a sighting system through the EVF. You can't take pictures through EVI for a long time - the eyes "fall off" very quickly. And live view ... Well, in the bright sun the LCD screen fades. So mirrorless is still a purely amateur option.

      • Morpheus

        bgg, what nonsense :) writes a man who did not hold in his hands a modern mirrorless

        • anonym

          And in what nonsense is it written? Or would you say that the matrix does not work there all the time? Not getting warm? Autofocus in many mirrorless cameras is much slower - that's a fact! And in those where he is smart - they have a price tag that it's easier to buy a good DSLR than this half-soap dish! About the viewfinder is also true - it fades in the sun even though you like mirrorless cameras. Plus lags, distorted color rendition and the battery eats in the end! Plus a hundred more nuances, because of which a mirrorless is a half-soap dish for show-off, but not for work.

          • Dmitriy

            As the owner of a Sony SLT camera, I can say that the only drawback is true "slowdown", although it only appears when shooting with low light (but the picture is visible with normal brightness, albeit with noise, so this is the same plus as a minus). When shooting with normal lighting, there are no delays at all. About the constantly turned on march - a fact, it's nowhere, but I'm not an astrophotographer. "Eyes" from EVI again do not "fall off". Bataraya is also a fact, but according to the characteristics of cameras, it is not particularly critical for the number of shots. But about the trick - that's for sure, the truth does not concern me, but the difference between my SLT-A37 and NEX-5N, for example, is simply striking. True, again, now there are matrices with built-in focus sensors, with which the speed of the camera catches up with the DSLRs at once.
            This is the obvious plus of mirrorless cameras - weight and size, but this is not the topic.

            • Do_Oraemon

              Of course, they don’t fall off, yeah. If you are into photography, you’re a hobby and you don’t click reports or weddings for days, then yes. But if photography is a profession for you, then ditching your eyes with such a viewfinder is easy. After some hard work, you yourself will notice eye pain in the morning.

          • Adam

            "A half-dish for show-off ..." :)
            I see emotions, but not awareness. Mirrorless cameras don't stand still. Look at Sony a6000 tests for example. There you have a battery, autofocus and so on. I'm not saying that mirrorless cameras are made for work, but blurt out about "half-soap" ... Very soon, younger DSLRs will have no advantages, and they will go to the past

    • Az

      Like a soap dish, it measures the exposure due to the software processing of the signal from the matrix by the processor and not due to a special sensor! Therefore, lags and brakes while he calculates what and how in this picture. In mirrorless cameras, as I noticed, in the first frame they are saved in speed only by the fact that all the time they work they are trying to “catch the frame” and focus on anything, and a normal camera does this when you half-press the shutter button. But with the second shot taken immediately after the first one, you immediately realize that you still have a soap dish in your hands, which begins to fidget with the lens trying to visit.

      • Gene jb

        Here you are wrong. Some cameras have a built-in phase sensor in the matrix, like on a central locking cylinder. Nevertheless, I also have a bad attitude to mirrorless. Although soon they will catch up and overtake the DSLRs. Already the pixel density of the LCD has become very large, and AMOLED is developing. So most likely EVI will soon be pretty enough.

        • anonym

          Some yes! But the cost for now is like an advanced amateur DSLR like D600!

    • xEzhik

      And I will continue to shoot with film Praktica L2 (the one without a light meter at all) and enjoy photography ...

  • Yarkiya

    Spoiler: CCD Nikon from time immemorial use full-color RGB CCD-type sensors for metering and do not know grief :)

    Reading, I rub my hands and giggle rejoice. ;-))

    • Lef

      And at the same time, my Nikon D3000 often misses with an exposure with a 44m-4 helix, even on an open diaphragm (no jumping rope)

  • anonym

    We look at the JVI of crystal clear purity will not be replaced by tempting songs about mirrorless :)

    • Oleg

      the OVI view does not give a real picture of what you are shooting, and only displays a fraction of the actual area of ​​the frame. and it is also impossible to impose any useful information on it - only a pale indistinct LCD display nearby, scanty in size. in addition, with OVI it is much worse to shoot with non-autofocus lenses.

      • anonym

        Correctly! Let's block the view with a bunch of information and icons! And let's not forget the tweeter, instagram, classmates and cloud drive icons! And so that it all shimmers with all the colors of the rainbow - this is the most important thing in photography! And also tips on how to make sponges a duck and in what position to stand in front of the mirror! Yes, and the tutorial right there to show which button to press! And it will be a hit! This is all so necessary for a photographer that it's just horror! Not like an incomprehensible pale screen next to some awful little tsyfirki!

        • Denis

          Yeah, how wonderful it is to accidentally hit the mode dial and click on a dozen valuable shots on the handbrake, completely lock them, due to the fact that the exposure and white balance are not visible in the OVI (but the last thing with it, if you shoot in RAW).
          And night shooting with OVI is generally delightful - looking into the darkness with numbers is so informative ... On the EVI you can see at least something when the gain from the matrix is ​​turned on.

          In general, I still do not understand what does the mirrorless have to do with it, in the article about exposure sensors ...

          • Do_Oraemon

            On the DSLR, the mode dial has never been touched. Moreover, I always do a little “shooting” before shooting - I don’t like to “draw” light and shadow in programs, although I shoot in RAV.

            Regarding night shooting, your remark is valid only for old SLR cameras without Live View.

            Mirrorless despite the fact that some comrade had the imprudence to write that the matrix metering system (which is used in mirrorless ones as well) is much more perfect. So a little srach came out.

        • Maksim

          Povnіstu pіdtrimuyu Anonіma!

      • Eugene

        “Displays only a fraction of the actual area of ​​the frame”.
        Unless on cropped cameras, on full-format cameras, the coverage area is 100%.

      • Do_Oraemon

        This is if the pens are curly.

  • Yarkiya

    It seems to me that you can put up with a mirrorless mirror only if it is full frame.
    And I still don’t understand why and for whom they make cameras one-on-one under a DSLR, but only soap dishes with a tiny matrix, like Fuji, with a hefty lens, with a pseudo electronic JVI. The effect of blurring the background occurs due to three frames with a shortage, focus and flight and gluing these three into one. Yes, and the price is higher than that of a DSLR.

  • anonym

    Well, and laughter, not a single wedding photographer or reportage would look at without a mirror) and above some mirrorless writers write real nonsense, not related to photography.

    • Yarr

      Yes, here experts gathered in kamenty))

      professional photographers people are usually a) conservative b) compactness does not bother them c) a large optics park, compatibility with a large number of specific photo accessories and the availability of developed technical support in their city are much more important for them

      that’s the thing, and not at all as mirrorless.

  • Alexander

    To each his own, to whom to work, to whom to rest! But a SLR is still preferable. I think many amateur photographers will cross the line, dummies,)

  • Denis

    For the photo of the Central Control Panel, for the rest there is a camera in the mobile.

    • Sasha, Kiev

      I agree. In modern smartphones, the level of the camera is in no way inferior to a soap box, or even superior. For non-artistic photos fit in 90% of cases.

    • Pastor

      I support. I have laptop 3 and comparing the same frames from a DSLR and from it in 50-70% of cases, my friends, who are not involved in photography, prefer the frame from the phone. This is because I show a raw image from a DSLR, and a bunch of "enhancers" are already turned on in the phone. As a result, there are more than enough phones for photography in the “I was here” style. Even some bokeh can be squeezed out of it, and sometimes even better than from a soap dish 3 years ago.

  • Dmitriy

    I’m ready to sell my soul just for the sound of the shutter. I did not like the Alpha 57 EVI in my hands. And about the fact that knocking down some parameter - it happens, but knowing this flaw, I often look at the upper additional screen, where everything except the exposure is displayed in my d90.

    • Maksim

      In the D90 itself and the decal, the parameter can be beaten, there’s already more than one pic, and in the new Nikons, everything is free, fresh, amateur, so that you can control all the parameters. As for me, it’s still a DSLR camera for photography, it’s not important that you are an amateur, you’ll probably want to use a DSLR camera.

    • Julia

      I join him, he returns me to my childhood when dad shot on his Zenith)) Well, now I put his lens on the CZK and enjoy life))

  • Dmitriy

    Thanks to Arkady for an interesting technical note. Somehow the theme just grew into a "holy war" mirror / mirrorless. And who can say anything about the work of exposure metering? From personal experience - it just exists and works :) Although sometimes it is not clear why the center-weighted metering in the SLT-A37 always measures in the center, even if the focus point is different. You have to measure with the center and then crop. Is it in all cameras or in more solid ones there is a snapping to the focus point / zone?

  • French

    ... "Spoiler: CCD Nikon from time immemorial use full-color RGB CCD-type sensors for metering the exposure and they don't know grief :)" ...
    ... this is, of course, only my subjective opinion, but b / w metering Kanonov takes a picture “in general”, entirely, hence, in my opinion, a more harmonious picture. like before". on b / w. And when there is a measurement by colors, it seems that some colors “pull the blanket” over themselves and the picture somehow ripples a little, too detailed ... once upon a time both systems were tested, so I chose Canon then. Then he worked already here (in Germany) in the publishing and advertising agency, so there was a large wardrobe with the entire line of canons and Nikons and there was a ts. a rule: Nikons were taken for the "reportage" (since they took all the details, good for printing), and for the artistic shooting, the Canons ....

    • Vadim

      An interesting experience.

  • anonym

    I don't understand your screams. The camera is bought according to the money and needs. Taking a family camera, for those who shoot, from time to time, “on vacation” and “barbecue in the country” is then better than ... Sony Cyber-shot DSC-100 or so on. It makes no sense to compare such cameras with Canon 600D, 650D, 700D, 60D, 60Da, 7D, 70D, 6D, 5D Mark III. For what I bought on that and take off. It makes sense to compare equal: 700D, 60D, 70D. You just need to note that progress is going forward, and few people want to shoot with a 40D Soviet lens. Take 60D. Mechanics are imperceptibly receding into the past, and in 20 years, most likely, cameras will not have mechanical assemblies, as we left the film.

  • Denis

    Autofocus confirmation sound comes from where?

  • Curious

    Do I understand correctly that the 63 zone old Canon sensors are quite sensitive to the use of aperture lenses on the camera?
    Those. when using 24-70 / 2.8, the exposure meter will work more accurately than 24-105 / 4 ??
    And will the AF module also be more accurate with 24-70 / 2.8 than 24-105 / 4?
    And yet - is there any difference which manufacturer to use lenses? Well that is 24-70 / 2.8 Sigma 24-70 / 2.8 EX DG will be detected as 2.8 even though it is Sigma ?? Or the camera will work well exclusively with native glasses and all exposure sensors and af will only work with native Lks.

    • Michael

      The exposure is hardly dependent. Autofocus - yes. This is not a software limitation, but a physical one, so autofocus will be more accurate with any light lenses. The difference is in terms of work algorithms. Non-native can lag

      • Curious

        I was interested in this phrase: “A similar mode is available in cameras using a conventional 63-zone sensor - 1D Mark IV, 1D Mark III, 1Ds Mark III. These cameras also have focus points and exposure metering paired. "
        Therefore, I suggested, reading an article by Arkady:
        what since AF module prefers lenses with f / 2.8 (and brighter), then the exposure meter, perhaps, will also work more accurately (or “differently”) with fast lenses than with dark lenses, with aperture like 4-5.6 (or, for example, Tamron 28 -300 / 3.5-6.3) ...

        • Michael

          Exposure metering is associated with autofocus only on top-end cameras, this allows you to understand the camera where the photographer is aiming (what is most important in the frame) and more accurately adjust the exposure. AF accuracy does not affect the operation of the exposure meter. Even if the AF misses half a meter, the camera still sees the spot where they were aiming. A bright lens can improve the operation of the exposure meter only in difficult conditions (darkness), when its sensitivity limit is reached.

          • Curious

            Michael, thanks for the conversation. Now it’s clearer. Have a nice day!

  • Andrew

    Hello, tell me please, can I make the Canon 7D so that the metering does not turn off after a few seconds? On Nikon, I did it without any problems.

  • Azake

    On my camera, constant overexposure in semi-automatic modes. By car everything is ok. Exposure compensation is set to zero. Peresvet on one stop. Therefore, for now, I’m shooting at minus 1. Who has come across this? How were they treated? I had this on a canon 5d2. I took it from my hands. It turned out that there is simply no focused screen. After installing it, the metering began to work correctly.

    • Azake

      The problem was solved after reducing the brightness of the screen to normal. Due to the maximum brightness of the camera screen, the photos looked very overexposed.

  • Azatbek

    because of this ifcl my camera shoots with obvious defects! This means shooting where there are bright spots that you focus on with autofocus. it looks like you are shooting in spot mode.

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