Flare through the JVI

The optical viewfinder transmits light from both the lens side and the eyepiece side. Due to the design features of the viewfinder of the SLR camera, the backward passage of light (from the side of the eyepiece) can adversely affect during shooting.

The eyepiece shutter arm that closes the shutter

The eyepiece shutter arm that closes the shutter

The optical viewfinder itself (JVI) does nothing wrong. But due to the fact that modern digital SLR cameras (and not only digital ones) have a metering sensor exposure mounted in JVI, light from the side of the photographer affects the exposure meter.

How it works JVI and metering sensor exposure you can see in the section 'Canon CCD Exposure Sensors'.

As a result, if the light source from the side of the photographer is strong enough, serious measurement errors may occur. exposure. A video is shown below, which clearly shows how easy it is to fool a camera’s exposure meter Nikon D700. On video Nikon D700 located with the bayonet cap closed and, if not illuminated JVI flashlight, it shows the shutter speed 'Lo' (insufficient light). As soon as you start to shine a flashlight in JVI, excerpt changes, which confirms the 'trick' of the exposure meter.

Advanced cameras have a special optical viewfinder eyepiece shutter that allows you to close JVI from light from the photographer. Curtain JVI it is recommended to close when the JVI is not used. Photographers taking a tripod are especially well aware of this. For everyday photography, this effect of illumination is extremely weak and can be neglected :).

Some cameras come with a special cap for OVI, which is installed instead of a soft eyecup. You can buy this plug separately. There is one inconvenience with such a plug - to install it, you need to remove the eyecup and not lose it :).

Another negative aspect from the passage of light through the JVI from the side of the photographer is the possibility of light exposure. Theoretically, during shooting, the camera’s mirror rises and completely blocks the light coming through the JVI from the side of the photographer. But due to the complex structure of the mirror, which has a special translucent window and a second additional mirror, which is responsible for focusing, some of the light can break through the gaps and illuminate the picture.

You can see about the structure of the mirror in the section 'The nuances of the structure of the mirror in modern central control rooms'.

Below is a couple of frames from the camera Nikon D700 with mounted bayonet cap and closed / open eyepiece shutter. To achieve visual illumination, in all examples, I highlighted the JVI with the same flashlight.

The difference with the closed shutter of the JVI and with the flashlight open during subnetting

The difference with the closed shutter of the JVI and with the flashlight open during subnetting

As a result, such a strong exposure can seriously harm the future frame. Therefore, when photographing at slow shutter speeds, it is recommended to close the JVI. Photographers taking long exposures know about this kind of flare.

Below is shown how my other cameras behave with exactly the same flashlight illumination and at the same value excerpts and ISO sensitivity.

Nikon D80:

No flare

No flare

Canon EOS 5D

Palpable flare

Palpable flare

Canon EOS 350D Digital:

No flare

No flare

In fact, everything is not so smooth with cropped cameras. Most likely, due to the reduced mirror, the number of gaps in the 'crop' is proportionally less than that of full-size cameras. But if the source of illumination from the OVI side is amplified and removed at a higher value of ISO sensitivity, then the result will not be animate.

Nikon D80, but with other parameters:

Strong flare

Strong flare

Canon EOS 350D Digital, but with other parameters:

Strong flare

Strong flare

When shooting at short exposures, there is no noticeable effect due to exposure from the AIS side. By the way, measurement errors exposure absent when working with electronic viewfinder :).

More videos can be viewed at my youtube channel.

↓↓↓ Like it :) ↓↓↓ Thank you for your attention. Arkady Shapoval.

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Comments: 29, on the topic: Flare through the JVI

  • Yarkiya

    I was filming today with a tripod and an IR remote control, at the beginning the thought flashed “should I cover the viewfinder”, but, as it flashed, it flashed. It will be necessary to carefully consider all the nuances.
    Thanks for the article, a very useful reminder.

  • Vladimir

    Thank you for reminding. :)))

  • Konstantin

    Are there such devices on the JVI that when you move the camera away from your face, the shutter closes? There is a similar thing on optical sights - there the illumination turns off when the eyecup moves away from the eye.

  • Denis

    On my Canon 350D, the viewfinder cover is on the strap, it's rubber. If I hadn't read the instructions, I probably wouldn't have guessed :)

  • Victor

    So, if I always do night shooting in Live View on the Nikon 5100, then you can not bother about the flare?

    • Denis

      No, because the light through the OVI and mirrors can still give a flare. Live View or not - in this case only affects the exposure meter.

  • Alexander Malyaev

    Thank you, Arkady, now I know how to shoot the “polar lights”. :)

    • Yarkiya

      Alexander, did you figure out the latch of the diaphragm ring at 70-210?

      • Alexander Malyaev

        Yes, it miraculously earned me when I did everything in every possible way with the lens taken from the camera. I could not return it back to a non-latched state, and in fact I did not try to break it much.

        • Yarkiya

          Well, fine, I wrote to you in the thread about this lens that the latch works if you pull it and release the ring if you click.

          • Alexander Malyaev

            Thanks! Didn't revise the branch. I told Arkady that it was necessary to add the function of the list of new messages in the topics, subscribe to comments, and indeed a lot of things are missing for the functionality of a modern blog. Well, now it's clear what kind of “wonderful image” it was.

            PS Arkady: of course I like to joke, but seriously, after such demonstrations I’ll definitely look for a stub on the viewfinder.

  • Valery

    Ah well done!

  • Vladislav

    “There are no errors in metering and long exposures when using the electronic viewfinder or during Live View”
    - I agree about errors in exposure metering, about exposure - no

    • Arkady Shapoval


  • Artem

    Sometimes I just do not rely on the shutter lever of the eyepiece :) It seems to be such a trifle, but so pleasant :) In one touch closed, in one opened. Without removing the rubber eyecup, quickly and conveniently. Everything ingenious is simple, thanks to Nikon and Arkady for their work :)

  • Uladzimir

    And when I shoot from a tripod, I cover the camera with a cap (hat), from the side of the OVI. Because it takes a long time to remove the eyecup and then put it on. The canon 7D does not have such a pesky shutter lever, unfortunately, as on this camera (Nikon D is something there). I'd say it's just a manufacturer's mistake. Indeed, the detail is cheap, but very necessary, especially for my camera, which is positioned as well, almost professional. Therefore, a cap is used. The advantages of this method - my cap is compatible with all models of SLR cameras of any manufacturer. :-) Happy all!

  • for

    There was a case, I wanted to start taking a selfie with a friend on the yacht, and now the setting sun hit the viewfinder)))
    I had to close my finger so that there was no second black frame

  • Nikolai (sn797)

    A cap is cool :) but, alas, I don’t wear it, so I use a rubber pad, exactly the one that all canons have on the strap. I took it off a long time ago and keep it separately in my backpack. When I take pictures of objects and I know that in the near future I will not go out into the street, then the pad is constantly on the camera. And on the street, in rare cases, you can cover the viewfinder with your hand ... Yes, I admit, take off the eyecup, then put on the overlay, then the other way around is troublesome. P ... the date lever on the D700 is a necessary and convenient thing, a similar, or rather, identical thing is on all ones, alas, on the seven, the manufacturers, for some reason, squeezed it, and positioned the seven as a camera made based on surveys of thousands of photomaniacs :) So, yes, it’s worth thinking about the cap :) I repeat, all happy! Let's hope for a better year ...

  • Sashko Fujifilm X-E2

    I think the illumination through the viewfinder happens because if you look into the mirror shaft on the upper pentaprism, you will see that when the mirror jumps up so that it does not clack much and does not break from a sharp impact there is a foam border around the perimeter of the pentaprism, the mirror hits the foam rubber, and then returns to its original position, making less noise. So, this foam rubber tends to let in a little light, and if you have an old camera from which sand is already pouring, a la NikAn Dы 700, then this foam rubber could completely crumble from old age or become stale. Nothing is eternal. To be honest with you guys, to get rid of all these ailments you need to buy a Fujifilm X-E2 and forget about flares, mirrors, shutter life, viewfinders, exposure compensation, and more ...

  • Yurok

    All my questions were exhausted after watching the video with a flashlight !!!!!

  • varezhkin

    the new d750 won generally reflects from the reflections from the AF module, illumination through the JVI then seems like a fairy tale.

  • Anathema

    The instructions write about using the cover on the viewfinder for slow shutter speeds and using an IR remote control or self-timer.

  • Anathema

    Forgot to write - Pentax K10d camera

    • Victor

      This is because when you look into the viewfinder, the eye instead of the cap :)

  • anonym

    I could not even think that this could be !! Thanks for the interesting fact !!

  • Alexey

    Right now the people are reading and will be paranoid on this topic. In fact, as a percentage of 95, probably cases, no covers are required. Try to come up with the conditions in which it would be noticeable. Of course, it is better to shut up at very long shutter speeds, but you definitely do not need to bother about this.

  • Arkady Shapoval

    Well, actually, the same conclusion is indicated in my article.

  • Charles

    Isn’t fate destroying the manual?

    • Arkady Shapoval

      always someone comes to be smart :) so, in exposure mode 'M' (manual exposure control), many modern SLR cameras can use auto ISO, in which case there will also be an exposure error :). But, of course, you can use it in a complete “manual”, but this is only a special case, since it will not fundamentally solve the problem.

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