JVI or EVI

My experience with EVI (electronic viewfinder) consists in communicating with Sony a7, a7 II, a7R, a9 cameras, some mirrorless Panasonic, Olympus and Fujifilm. For a long time I shot on SLR cameras with OVI (optical viewfinder), and after them it was very inconvenient for me to use EVI, but over time I felt all its charms and radically changed my mind.

The internal structure of the camera

The internal structure of the camera

On the Internet, I often see phrases like "Once I tried EVI, I realized that this is not mine." Such words can be said about me, but, fortunately, life made me communicate with EVI more closely and come to different conclusions.

Please note that OVIs are of two types - for SLR cameras and for rangefinder (mirrorless) cameras. The JVI design for these two different types of cameras is fundamentally different. In this article, by OVI, I mean a viewfinder specifically for SLR cameras.

EVI, power consumption and inclusion

One of the most serious drawbacks of EVI is considered volatility. In order to see what you want to shoot, in the case of EVI, the camera must be turned on. In this case, the matrix of the camera will be turned on, the processor and the EVI sensor will work. All this consumes energy, and even worse, it takes time to turn on the sensor, processor, and other hardware. As a result, there is a huge lag between turning on the camera and displaying the image.

Electricity consumption can be cured with more capacious batteries, or spare batteries - it's not a big problem for me... But the EVI lags when turning on, turning off, exiting the camera from sleep mode, activating the sensor after it was turned off while viewing the footage, and so on, get on your nerves. Lag when turning on EVI - biggest flawwhich I highlight in EVI.

This drawback can be easily solved - for example, always keep the sensors on, or just make the lags very short. I believe that in the future there will be no problems with power consumption and lags when turning on / switching a camera equipped with EVI.

Is the finished result really visible in EVI?

A strong advantage of EVI is the ability to see the finished result before releasing the shutter. But there are reservations. The observed image is formed by a sufficiently small sensor of 1-2 Megapixels, which does not transmit the entire amount of data received from the camera’s matrix. In this case, the JVI is more informative, the matte screen of which, in fact, has a very large resolution. Also, the camera processor is not able to immediately apply all the enhancements for the image, such as control of dynamic range, color, noise reduction, distortion and vignetting. As a result, the image after the shutter is released may still be slightly different from the one I see in EVI.

The Sony a7 camera is very noticeable that the image is still being finalized after the shutter is released. It often happens that after the shutter is released, the camera shows the shot, it takes 1-2 seconds and the picture changes its appearance - it undergoes additional processing, which could not be obtained immediately.

I really like that when working with EVI, a finished picture (obtained after releasing the shutter) can be viewed immediately without taking your eyes off the camera’s eye. In the case of the JVI, you need to take the camera away from your eyes and look at the main display to see the received image. It turns out that with EVI much less time is spent on monitoring the shot material.

As for the small differences from the image observed in the EVI and the final frame (after releasing the shutter), this is just a processor limitation, which can be easily cured in the future. Yes, and many cameras already fully display in EVI directly the frame that will be after the shutter is released - with all additional image quality adjustments turned on.

EVI in the studio

Usually, sighting through an EVI makes it possible to observe the picture that will be at the time of shooting, but this may not always be convenient, and sometimes it is contraindicated. This primarily concerns shooting in the studio using pulsed light. The bottom line is that in the studio all frames are usually shot with manual settings exposure. For example, in the studio it is most often used exposure control mode "M". Suppose I set ISO 100, F / 4.0 and 1/125 sec. With these settings, the camera’s EVI will display a black rectangle, since there can be very little pilot light (pulsed flashes will be used at the time of shooting). It is practically impossible to focus on and compose the frame in such conditions. To overcome this inconvenience, on cameras with EVI there is a function that disables “displaying pictures with actual parameters” and includes “display simulation”. In simulation mode, the camera does not use user-defined parameters. exposure, but selects its optimal ones, in which the EVI produces a distinct image, through which you can focus on sharpness and compose the frame. If you turn on the simulation, then in this case it will be very convenient to endorse in the studio.

In the Sony a7 camera menu, the function that is responsible for the display mode is called 'Display. Live View '(Setting whether to display settings such as correction exposure, on the display screen). This function can take only two values ​​“Display. Param. ON ”and“ Display Param. Off. "

When I first got into a studio with a mirrorless camera using EVI, I did not know about the possibility of simulation and it was very difficult for me to shoot.

Of course, simulation of the display can be useful for other types of shooting, for example, for shooting with very slow shutter speeds.

Inertia EVI

EVI suffers from inertia - when rearranging a frame, the display of changes may occur with a delay, and the EVI may slowly rebuild with a strong change exposure filmed scene. For example, if I was shooting in the shade of trees, and sharply pointing the camera towards a bright street, then in EVI instead of the expected type of street, for an instant I will get a white spot that has normalized and will take the expected form over time.

With a sharp change in lighting, the Sony a7 loses consciousness and within a few seconds adjusts to the correct exposure.

Most likely, this drawback can be eliminated and in the future cameras with EVI will be deprived of this drawback.

Pixelization

They say that one of the main problems of EVI is the pixelation of the image. Perhaps this was a problem many years ago when sensors for displaying images in EVI had low resolution. With the cameras that I indicated at the beginning of the article, I did not observe or did not notice the pixels of the EVI display.

If some EVIs have such a disadvantage, then over time the number of pixels on the EVI sensors will increase and everyone will forget about this problem.

Feeling of light

The EVI sensor has a constant or variable brightness within certain limits. On the one hand, this is a great achievement compared to the JVI. In the JVI, the brightness directly depends on the maximum aperture of the lens and the illumination of the scene. But constant brightness can play a trick on the eyes of the photographer. When shooting in bright light, I often saw that when I was vising through the EVI, my eye was tuned to a certain light intensity, and as soon as I took the camera away from my face and looked at what was happening without EVI, it took my eyes time to change to another illumination. The same thing happens when in the bright sun you bring the camera to your face, while in EVI you can’t see anything for a while until your eyes accommodate.

I think that this drawback of EVI can be solved with brighter sensors, as well as light sensors (similar to those that are in modern smartphones and automatically adjust the brightness of the display depending on the light).

Viewfinder linked to focus system

Speaking about EVI and OVI, you need to immediately understand that the technology for displaying the future frame is directly related to the focusing system. Very fast and fairly accurate phase focusing systems based on separate sensors have been developed for the OVI. For EVI, phase or other focusing sensors should be placed directly on the camera’s matrix (SLT cameras do not count, since there is a mirror). So far, there is an opinion that focusing on mirrorless cameras with EVI is noticeably worse than on SLR cameras with AVI. But in fact, mirrorless cameras with EVI only need to pull up and refine their focus system a little, and some cameras with EVI focus already very, very well. Separately, there are SLT cameras, which also use EVI, but at the same time they have a fixed mirror and phase focusing modules, which are characteristic of cameras with AWI.

Conclusions on EVI and JVI

Advantages of JVI

  • JVI non-volatile, works even when the camera is turned off. True, modern OVI in some cameras have their own limitations, which are primarily associated with a transparent LCD display for displaying auxiliary information. I have considered this issue in detail here.
  • Lack of inertia, instant sight of the scene. Very important for reportage photography.
  • High matte screen resolution with the possibility of replacing it.
  • The brightness of the JVI automatically changes depending on the scene being shot.
  • Subjectively, many users like the non-digitized image from the JVI more than the digital image when sighted through the EVI.

Disadvantages of JVI

  • The high cost of production and design complexity. For JVI, you need a very large number of mechanisms that can fail (tested more than once on personal experience). First of all, JVI needs expensive glass pentaprisms, mechanics of mirror control (two mirrors), separate metering sensor and separate focus sensor. When the cost of production is reduced, for example, when replacing a pentaprism with a pentamirror, the display quality decreases.
  • For accurate and perfect focusing, the mechanisms of the mirror / second mirror and the focusing module need to be very precisely calibrated; it is sometimes extremely difficult or impossible to programmatically make accurate focusing with each lens.
  • Simple ARIs have 90-98% of the frame coverage, the remaining percentages at the edges of the image are not visible. In expensive models, the percentage of frame coverage reaches 100%, but the cost of creating such a JVI increases. Details therefore you will find here.
  • Noise at work. Part of the shutter noise It is created directly by the movement of mirrors and their control mechanisms.
  • The movement of the mirror creates excess stirringthat may affect image blur. Some cameras have a tangible Mirror Shock.
  • Focus area limited by focus points due to reduced additional mirrorresponsible for focusing.
  • Image distortion. First of all, the JVI incorrectly displays the appearance of the blur zone, the bokeh when viewed through the JVI is not displayed at all what it will look like after the shutter is released. Also, when working in backlight, the final shot may have light artifacts (reflections, glare, etc.) which are not visible in the JVI.
  • The opaque OVI screen, mirror and matrix may become dirty, which reduces comfort during shooting. In EVI, only the matrix is ​​contaminated.
  • You cannot shoot video through the JVI. On cameras equipped with an OVI, the main display with the Live View function should be used for video recording.
  • JVI has a certain dimming timewhen the mirror is in a raised state. In this position, focusing and metering also stop. exposure. In some cameras with EVI it is possible to constantly sight, even when shooting in a series, and focusing can work constantly, but for this you need to use an additional electronic shutter (not all cameras with EVI have an electronic shutter).
  • JVI may suffer from flarethat affect metering exposure and / or illuminate the image for long exposures (this disadvantage is treated with a special eyepiece shutter, I examined this issue in more detail here) But EVI is completely devoid of flare.
  • JVI requires use retrofocus wide-angle lenses (due to the presence of a mirror, the working length is lengthened).
  • OVI does not allow you to visually stabilize the picture when using the image stabilizer built into the camera. To stabilize the image in the JVI, you need to use lenses with a stabilizer
  • JVI sometimes does vacuum cleaner effectwhich can be unnerving.

Advantages of EVI

  • When sighting EVI immediately displays that imagethat will be obtained after the shutter is released (with some reservations described in this article). Also, in the EVI it is convenient to see the real-time image settings and select the best option.
  • The conclusion is very ba lot of supporting information. First of all, it helps to use a number of very useful functions, for example: focus picking, live bar chart, function - "zebra", electronic level and many others. Also, EVI allows you to instantly increase the selected part of the frame in real time, which can be very useful for accurate focusing.
  • EVI allows you to view the photo you just received without taking your eyes off the eyepiece. Allows you to more quickly control the quality of the filmed material.
  • The focusing method used with EVI is less prone to problems with back / front focus.
  • Allows you to dig into all the settings of the camera without taking your eyes off the eyepiece EVI. In the case of the JVI, to access all the settings, you should remove the camera from the eye and turn on the main display.
  • Constant, or automatically adjusted brightness at any aperture value, excerpts and the scene being shot. EVI brightness does not fall when closing the iris, for example, to view the depth of field.
  • Simplicity of construction (unlike the OVI, it does not require mechanical mirrors, a matte display, a pentaprism, an additional focus sensor, an additional metering sensor exposure and heaps of serving devices). Also, this design allows you to make cameras more compact and lightweight.
  • EVI works silently (unlike clapping mirrors), and also does not create unnecessary movement from the movement of the mirror.
  • EVI has a greater potential to expand the area of ​​the frame responsible for focusing. Theoretically, the entire area of ​​the frame may be responsible (or already responsible in the case of focusing by contrast) for focusing.
  • Large (in fact 100%) percentage of frame coverage. In the JVI, it is not so easy to achieve 100% frame coverage.
  • The ability to simultaneously sight through the EVI and connect in parallel other devices for image output. For example, you can connect a monitor to the camera with EVI, through which other participants in the shooting will see what the photographer is taking, without disturbing him at all.
  • From the previous it emerges that EVI allows you to shoot video.
  • EVI allows you to visually stabilize the picture when using the image stabilizer built into the camera
  • Shutter release time may not be available when using the electronic shutter.
  • Missing Mirror Shock

Disadvantages EVI

  • Inadequate brightness. On a sunny day, it constantly seems that the image in the EVI is too dark (in the future, the flaw can be corrected)
  • Low resolution of the sensor, forming images for display in EVI. Here you can add low-quality sensors, which when sighted create various unpleasant visual artifacts (in the future, these shortcomings can be corrected)
  • Volatility (theoretically it cannot be fixed, but in the future it can be improved by using sensors with lower power consumption and more capacious batteries, not everything is so bad now)
  • Inertia, lag in image output (in the future may be fixed)
  • Power-on lags or at low temperatures (may be fixed in the future)
  • Matrix heatingoverheating of the matrix, which in the first place can be negatively displayed at the noise level (in the future it can be fixed)
  • Difficulty working in low lightrelated to the brakes of image display and / or displaying an image that is too dark (may be fixed in the future)
  • In EVI artifacts from a dirty matrix are much more noticeable, this reduces comfort during shooting (in the future it can be fixed with an improved matrix cleaning system)

Some of these deficiencies have been corrected to one degree or another or are actively being corrected.

I can summarize that EVI technology has a lot to develop, its shortcomings can eventually be improved by the best hardware and software solutions. OVI technology has reached its logical end and does not have serious opportunities for improvement. At best, the JVI will move toward a hybrid JVI. Nevertheless, you need to understand that the JVI is a very ancient, proven technology that will please more than one generation of photographers.

Materials on the topic

  1. Full-frame mirrorless systems. List of all cameras and lenses to them. Mirrorless fever, discussion, choice and more
  2. All cropped mirrorless cameras, discussion of systems
  3. Mirrorless crop that has stopped or is stopping its development
  4. Fallen Digital Mirror Systems
  5. JVI or EVI
  6. About mirrorless batteries
  7. Simple and clear medium format
  8. Smartphone Impact
  9. All announcements and news
  10. What's next?

Comments here on the site do not require any registration. In the comments, you can ask a question on the topic, or leave your feedback, or describe your experience. For the selection of photographic equipment, I recommend E-Catalog. Many little things for the photo can be found on AliExpress.

The material was prepared by Arkady Shapoval. My Youtube channeland Radozhiva's group on Facebook и VK.

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Comments: 245, on the topic: JVI or EVI

  • Eugene

    Very useful information ..

  • Alexander

    Good day. Please tell me, are these minuses still relevant for EVI, three years later? Today, the question is between Canon 800D and Canon M50. In particular, Inertia is concerned, in general, and especially in low light.
    Thank you in advance for your reply.

  • Paul

    Good afternoon!
    Thank you for the article. I’m thinking about switching from a SLR to a mirrorless one, the viewfinder is the main stop factor.

    Your article is good, but very important information is missing since you are making a comparison. You write: "As a result, there is a huge lag between turning on the camera and displaying the image." Is this lag in milliseconds or seconds? Similarly with the inertness of EVI. How much to wait?
    I mainly shoot reports and if the lag when switching on or a sharp change in composition is more than a second, then this is already critical.

    Thank you

    • Arkady Shapoval

      Very much depends on the specific camera. There are seconds, there are milliseconds.

  • Bogdan

    And there is one more nuance, there is little to say about it, When you use a mirror with a mirror from your hands, you trim the camera with both hands, and turn my stench on your knees. With mirrorless cameras, with a video through video, your head will serve as a third point of support, so kindly stabilize the camera.

  • Alex

    EVI is also becoming even more inhibitory in the cold?

  • Ross Tucker

    Thank you for taking the time and for putting in the effort to research and write these articles. They have clarified several technical points which I was interested in or concerned about. Plus these articles are interesting and motivate me to read more of them and to research other technical areas as well.
    I was lucky enough to be researching about focus sensors in the Nikon line and one of the online articles I ran across linked to your site. I've managed to use the web based Google Translate to enable me to read your articles. My Android phone also has a Google Translate app which I use to translate the text in the images. Translations are not perfect but the intent is (almost) always clear after a moments thought.
    I own a D7500 and initially was interested in the D850. After about a year of taking in more information and after the Z7 had a Firmware upgrade to version 3.0, I'm seriously thinking about saving up for a Z7 instead (unless a Z8 is soon released).
    Thanks again for the excellent articles. Best wishes in staying safe during COVID-19.

    • Ivan

      It's unexpectedly to see the foreign reader in the Russian language site. Nice to meet you, Ross Tucker! About a full frame camera, l would prefer D850 instead of Z-series. In my opinion COVID-19 it's the global fake to make new financial economic world. C-19 is no more dangerous than ordinary flu.

  • Alexey

    EVF is extremely poorly suited for people with low vision. Few cameras allow, in principle, adjusting the diopter correction to obtain a normal image if the operator is wearing glasses. Usually there is not enough adjustment range. In addition, many people with poor eyesight, even after relatively short viewing of the image in the EVF, begin to ache and watery eyes. I have myopia minus seven, tried to shoot with a variety of cameras with EVF - the result is sharply negative.

    • BB

      Vision -2 / -3 + astigmatism, I put on contact lenses for long surveys. I did not experience any problems with any viewfinders. Although I prefer JVI.

      • Alexey

        not so simple. I knowingly indicated the degree of myopia. and I can add that with such a high myopia, I already completely have no accommodation. so lenses or corrective surgery will only add to the problem.

        • BB

          For minus seven I will not say anything, for my wife minus six - she takes off normally in the lenses. Of course, if you look at the monitor / viewfinder / phone all day, your eyes get tired, but in any case it is more comfortable than wearing glasses.

          • Alexey

            the key word - no accommodation - says something?

  • US6IBD

    When using OVI in DSLRs, fast phase focusing takes literally milliseconds. When using EVF, the contrast focusing mode is very slow. Takes 1-2 seconds.
    The rest of the parameters, such as the shake from raising the mirror, do not even consider. The mechanical shutter itself creates sufficient movement.
    When using the ZM-6a with a converter * 2, on a sufficiently powerful tripod with a weight of 5 kg, I observe on the screen in live view mode (without raising the mirror), when the shutter is triggered, the fading oscillations of the image are 3 ... 4 sec.
    All information is displayed on an additional LCD screen.
    And of course I don’t want to warm the matrix and consume battery power.
    As you understand, I am for the JVI, although my vision is -4 and I am wearing glasses!

    • US6IBD

      And by the way, in connection with the retirement age, there is also no accommodation. I use several different diopter points for different situations. You have to put up. :-)

  • Dmitry (e_dimas)

    "A strong advantage of EVF is the ability to see the finished result before the shutter is released."
    This is an advertising LODGE!

    Arkady, why don't you want to honestly write that before pressing the "trigger", on the screen and in the EVI, we see only an IMITATION of the future frame?
    (Some manufacturers of photographic equipment honestly write about this in the instructions, and warn that the photo may differ from what is displayed on the screen)

    I understand why some manufacturers and sellers are trying to trick us (to get a new camera in, despite the fact that my current camera shoots well), but why reputable photographers repeat this box, I don’t understand.

    • B. R. P.

      You seem to have read inattentively. After the phrase you are quoting follows a text explaining some points.

    • Arkady Shapoval

      It is not clear to me how you read and skipped the whole section about it. The section is called “Is the finished result actually visible in the EVI?”. I wrote everything honestly and constantly supplement this article, it is unlikely that you have the right to write to me here about "advertising" lies :)

      • Dmitry (e_dimas)

        In the first sentence of the section, you write:
        "A strong advantage of EVI is the ability to see the finished result before the shutter is released."

        In the penultimate sentence, you write:
        "Regarding small differences from the image observed in the EVF and the final frame"

        So we see the finished result before the shutter is released, or all the same, the images before and after the shutter are different ???

        • Arkady Shapoval

          Re-read everything again without pulling out phrases.

          For example:

          A strong advantage of EVI is the ability to see the finished result before releasing the shutter. But there are reservations.

          Or do you really something is not clear or do not agree with something? You can describe your thoughts and your experience, it will be useful to readers (I hope).

          • Neo

            If a person is convinced, then no explanation will help him. Though standing on your head, Arkady, just ignore such experts;)

          • Dmitry (e_dimas)

            We cannot see the “finished result” until the shutter is released!
            Before the shutter is released, we see the IMPOSITION OF THE EXPOSURE which does not always correspond to the finished frame. (you yourself write about this in the same article)
            And this imitation is not a virtue, because in practice the exposure indicator and live histogram are more useful.

            Such phrases mislead people and make you believe in something that is not really there.
            And as we can see from your “FANS”, people truly believe in this.

            • Arkady Shapoval

              That is, sometimes the exposure corresponds to what will be in the picture. And those cases when it does not correspond, for example, with pulsed light, are described here. As described imitation. Still I can’t understand what are you leading here

          • Dmitry (e_dimas)

            However, write what you want.
            The truth has long been, the cheapest and no one needs the goods.

            Your fans worship you already.

            • Arkady Shapoval

              If you have the truth, share it. So far, I do not see in your words any conflicting data from my article. I see only a run over on EVI, while there is no objective approach yet

    • Alexey

      since I was not given to shoot on the UPC and use the EVF for reasons of strong myopia, I will say that I see my canons on the display in LV mode - and I see a fairly exact similarity of what will then be in the picture. brightness (shadows and light), color, depth of field - everything is almost the same as it will be as a result. moreover, I adjust WB in Kelvin by looking at the display itself. (although, to be honest, I will say that the displays of my cameras are color-calibrated by me personally, which is not the case with conventional cameras)

  • Dmitry S.

    Hello.
    Question on EVI in Sony cameras. Along the perimeter is the display of technical information.
    Is it possible to remove all this in the camera settings so that only the bottom line with key information remains? Otherwise, it turns out that it is impossible to control the shooting process along the perimeter of the frame. Suddenly there is a photo rubbish ...

    • Arkady Shapoval

      Yes there is. You can remove everything at all

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English-version of this article https://radojuva.com/en/2015/11/ovi-i-evi-ovf-and-evf/