Autofocus 40 / 0.8 and manual 40 / 0.75 (EGF and ED for DOF)

Everything is very simple. Many lenses for full frame cameras (narrow format, 36 x 24mm sensor / film size) cover fairly well medium format sensors with crop factor Kf = 0.79X.

manual 40 / 0.75

manual 40 / 0.75

I like the most simple and straightforward medium format cameras from FUJIFILM, namely the series FUJIFILM GFX... It is very easy to find autofocus adapters for these cameras for using full-frame DSLR lenses.

Hasselblad X1D и Hasselblad X1D II I do not consider them, they are difficult in that they have to use lenses with a central shutter blade, which makes it difficult to use third-party non-original full-frame lenses.

Other Medium Format SLR Cameras (Pentax 645Z, Leica s3 etc.) and medium-format modular systems (Phase One, etc.) are not suitable, since they do not allow easy and simple operation of full-frame reflex optics due to the difference in focal lengths.

FUJIFILM GFX sensors have crop factor Kf = 0.79X, which is why equivalent focal length (EGF) и equivalent aperture in the calculation of depth of field can show amazing combinations:

  1. 85 / 1.2 -> 67/0.95, autofocus Canon Lens EF 85mm 1: 1.2 L и Canon Lens EF 85mm 1: 1.2 L II
  2. 105 / 1.4 -> 83/1.1, autofocus Sigma 105mm 1: 1.4 DG Art for Canon EF
  3. 50/1 -> 40/0.8, autofocus Canon EF Lens 50mm 1: 1.0 L
  4. 50 / 1.2 -> 40/0.95, autofocus Canon EF Lens 50mm 1: 1.2 L

Autofocusing with Canon EF lenses is very easy with the appropriate adapters / adapters, for example Viltrox EF-> GFX, FotoDiox EF-> GFX, TechArt EF-> GFX, SteelsRing EF-> GFX, Jintu EF-> GFX... There may be autofocus adapters for other full-frame SLR systems (Nikon, Pentax, Sony) on the FUJIFILM GFX, but the Canon EF system remains the most interesting for such experiments, only it has full-frame DSLR lenses with F / 1.2 and F / 1.0.

Exclusively and for relatively little money, you can still get a unique set of FUJIFILM GFX 50R (approximately $ 4000), ZHONGYI Speedmaster EF 0.95 / 50mm (about $ 800) and a simple adapter K&F Concept EOS-GFX (approximately $ 40), which will have an EGF and an equivalent depth of field 40/0.75. Let me remind you that ZHONGYI Speedmaster EF 0.95 / 50mm is the fastest full-frame lens for DSLR cameras. And if you don't want to bother with adapters, then you can look at the fastest lens for medium format cameras - Mitakon 85mm F / 1.2, which immediately goes under the FUJIFILM GFX mount and gives the equivalent of 67 / 0.95.

It's important: some readers still did not understand that this is not about aperture (T-feet), but about the recalculation of the equivalent aperture in terms of depth of field. The same applies to the equivalent focal length (EFR). Aperture (T-stop) and focal length (namely the physical focal length of the lens) when using adapters does not change.

More materials on the topic

  1. Full frame mirrorless systems... Discussion, choice, recommendations.
  2. Cropped mirrorless systems... Discussion, choice, recommendations.
  3. Cropped mirrorless systems that have stopped or are no longer developing
  4. Digital SLR systems that have stopped or are no longer developing
  5. JVI or EVI (an important article that answers the question 'DSLR or mirrorless')
  6. About mirrorless batteries
  7. Simple and clear medium format
  8. High-speed solutions from Chinese brands
  9. All fastest autofocus zoom lenses
  10. All fastest AF prime lenses
  11. Mirrored full frame on mirrorless medium format
  12. Autofocus Speed ​​Boosters
  13. One lens to rule the world
  14. The impact of smartphones on the photography market
  15. What's next (smartphone supremacy)?
  16. All announcements and novelties of lenses and cameras

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

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Comments: 51, on the topic: Autofocus 40 / 0.8 and manual 40 / 0.75 (EGF and ED for DOF)

  • Tryamer

    I'm not sure if the depth of field is worth recalculating. The real aperture will remain the same, and the DOF corresponds to the focal length. One could talk about the complication of focusing on the OVI, due to a decrease in scale. And on the screen, it doesn't matter at all.
    It is also interesting that the Soviet medium format, in which the rear lens is not recessed into the body, cover the 9x12 frame. Even the Zodiac covers a 13cm circle. True, minus the lid attachment petals. They are in the frame. If I could find a compact shutter with a hole larger than that of a native compur, it would be possible to make a Photocor with interchangeable optics).

    • Arkady Shapoval

      Nowadays, both EGF and equivalent aperture are often indicated in terms of depth of field, this is already the norm. Of course, the aperture ratio (T-stop) will be the same.
      When the medium format becomes cheaper, the old Soviet medium format players will get a second life. For example, I am interested in Jupiter 250 / 3,5 in medium format.

      • Alexey

        In this case, an SF matrix with a 50 / 1.2 lens per unit of exposure time will receive the same amount of light from the same scene as a full-frame small-format matrix with a 40/1 lens. This is not only the equivalent DOF but also the real shutter speed or real ISO. However, this is obvious :)

        • Victor

          Are you saying that when you install a full-frame lens on the SF, the shutter speed at the same iso (say, 100) will become shorter?

          • Alexey

            Yes, the situation is the same as for crop / full frame. Full / even fuller frame only.

            • Arkady Shapoval

              Yes that's right. Conversion factors just go below one. In the case of a crop - above one

              • Trueash

                >> I've seen a separate exposure meter for a long time, if there is a shutter speed calculator for film cameras, then there is a frame size account, it's just always one. - So if I have Iskra, Zorky-4 and Chaika, I need three special exposure meters?

            • Alexey

              If the lens will cover the SF.

              • Arkady Shapoval

                Many full-frame DSLR lenses, with some caveats, can easily cover the Fujifilm GFX medium format. For example, the same Canon 85 / 1.2L (from a note) works wonderfully on the Fujifilm GFX medium format. There is a little trick here, namely that the Fujifilm GFX is not really a medium format, it can be called a “crop from medium format” with a crop factor of only 0.79 X. That is, in terms of the frame area, it is only 1.67 times larger than that of a frame 36 X 24. (For example, Full Frame from APS-C differs in area 2.25-2.6 times). Therefore, the linear dimensions of the sensor (not its area) in Fujifilm GFX do not differ so much from the full frame and are covered by a large number of full-frame SLR lenses. This is what some photographers use. Of course, in the corners and edges it will be sad: vignette, coma, chromatism. But, for example, for creative shooting on the same Canon 85 / 1.2L it does not play any role. Just look online for work specifically with the Canon 85 / 1.2L and Fuji 50r. It was the pictures from this couple that contributed to the writing of this note.

              • Alexey

                Yes, the difference in area with a full frame is not very big and you can expect quite acceptable performance of full-frame lenses. And full-frame lenses are more affordable. Maybe someday we will be able to use this :)

              • Victor

                2Aleksey: this is not “as I please”, but as it will be in reality. It's like proving that 2x2 = 5, and when it is suggested to count, it is offensive to quit “as you please, 4 so 4”))

            • Victor

              In general, the exposure should not differ. And why should she be different? The luminous intensity per unit area will be the same, obviously.

              • Alexey

                The sensor area is larger.

              • Victor

                2Alexey: so what? The shutter speed will still remain the same.

                You can put, and check, the same lens on: SF, ff, and double-crop.

              • Alexey

                As you wish.

              • Trueash

                A common misconception: “a larger sensor gathers more light”. That is, the tan in Viev will be stronger than in Brovary, because Kiev is larger: D

              • Victor

                What are we talking about :)

              • Arkady Shapoval

                Aperture, exactly the value that affects the shutter speed or ISO, does not depend on the format. The aperture ratio will remain the same, but only in the ideal case, if the lens equally and uniformly (in terms of vignette) covers both the SF and the crop. But roughly speaking, the shutter speeds and / or ISO will be the same.

                Once again: shutter speed and ISO with a lens like Mitakon 85mm F / 1.2 on Fuji medium format, full frame, APS-C, Micro 4/3, and even Nikon 1 and Pentax Q will be the same at the same values ​​of F.

              • Alexey

                (this is another Alexey :))
                this question is asked so often that I am tired of answering it. As an answer, if asked by the IRL, I am showing a simple experience. I put two cameras on tripods, crop and full frame, on each of them I put the same 50 1.4 and in M ​​mode I shoot a frame with the same settings. then I show what happened, show the histogram and, in LV mode, using ML, show the real brightness / RGB value in different parts of the frame. and everything is exactly the same. but even after that there are non-believers :)

              • Alexey

                Let's take a certain flat source of monochromatic radiation (infinite plane). Let this source give a sensor illumination of 1 lux. There is no lens yet. Lux is one lumen (luminous flux unit) per square meter. You can go from lumens to radiant energy (watts). They are related by dimensionless coefficients. Further, W = J / s. We know (calculate) the energy (in J) of one quantum of light. From there we come to the fact that the fixed illumination gives n quanta per second per square meter. This, however, is so intuitive. For a wavelength of 0.55 microns, an illumination of 1 lux gives approximately n = 4e15 quanta per second per square meter.
                Suppose we have sensors of different sizes, but the same ideal sensitivity (each incoming photon is considered). We put a lens covering any sensor.
                The number of quanta N falling from the source to the sensor (at a given illumination of the sensor, now already associated with the aperture of the lens) per second is equal to the product of the sensor area S (in m2) by the time (in seconds). If we count and add all the quanta of light, then the resulting sum of quanta for the same time will be directly proportional to the area of ​​the sensor with the same lens. With the same sensitivity of the sensors, a larger amount will be received from the larger sensor during one exposure time. Or the photon counter after a larger sensor will accumulate the same signal as after a smaller one, but in a shorter time (exposure). So far, we were just filming a uniformly luminous target of the same color with different sensors with the same lens.

                If we consider a real scene, then for the same viewing angle, different sensors will require different focal lengths. Let a lens with a focal length of 50 mm for SF and 15 mm for Nikon 1 be stuck. The frame, if possible, was equally filled with the same equally illuminated scene. In this case, the illumination of the sensor will depend on the lens aperture. Let again the same sensitivity of the sensors. Let the lens on the SF be 50 / 1.2. For one second of exposure from our scene on the SF with a 50 / 1.2 lens, we received N quanta (we will not distribute them spatially across the scene).
                The challenge is how can we get the same amount of quanta from a Nikon 1 sensor with a 15 mm lens in one second (the same shutter speed)? The sensor area is 13 times smaller. If the illumination of the sensor is the same, then there is no way to get it. We'll have to increase the exposure 13 times.

                Another option is to increase the illumination of the Nikon 13 sensor relative to the SF sensor by 1 times, or rather the luminous flux. It will be necessary to either increase the illumination of the scene or collect everything up to the last reflected quantum with some kind of abstract lens 15 / 0.45 (if there is something to collect).

                It's all obvious. For this, large sensors are made, not only for the sake of a small depth of field.

              • Arkady Shapoval

                But some will believe it. And if on SF the exposure should be 1/1200, then on Nikon 1 it will already be 1/100 :). It's good that it isn't

              • Rodion

                Alexey, you know what lux and lumens are, but you are confusing integral and differential physical quantities ... The sensor consists of many pixels, and is not a single pixel.

              • Victor

                Excessive theorizing leads to this. After all, I specifically asked at the beginning a specific question - will the exposure be different with the same iso.

                Much more specific :-)

              • Arkady Shapoval

                > Victor
                shutter speed will not change (minor errors due to vignetting [exposure on the periphery of the frame] and framing [different focusing distances and, as a consequence, different effective focal lengths for some types of lenses] can be omitted)

              • Alexey

                No Rodion, fundamentally nothing will change if we take a detector from one pixel (photocathode) or start dividing it. The objections of the rest of the participants in the discussion have no arguments. Let it be as they please in their universe.

              • Alexey

                I have seen a separate exposure meter for a long time, if for film cameras there is also a shutter speed calculator, then there is a frame size account, it's just always one :)

              • Rodion

                Okay, Alexey, okay. They don't argue with heretics - they are burned.

              • Novel

                God, what a heresy. Aleksey, the lens, placed at the same distance from the sensor, forms the same circle of the same area, scattering the same photon energy on it (conventionally and on average). The small sensor “bites out” only the central area of ​​the same image, large, but still within the circle being formed, large.

                Okay, let's take an example. You have not one 36x24 sensor, but a sensor consisting of two 18x24 halves that can be switched on / off at will. Let's try first to take a photo with two halves of the sensor turned on, and then we get the same image with only one half turned on. Then we cut off half of the first captured image (so that it coincides with the second, initially half). Following your logic, the first image will be twice as dark or require twice as long exposure. But it is obvious that this is not so.

                Well, or if you half-seal your full-frame sensor with tape, it will require twice as long exposures. It doesn't work either. Reducing the sensor size on the same lens is like cropping in Photoshop.

            • Trueash

              Even easier: has anyone seen a light meter that sets the frame size?

              • Alexey

                (this is another Alexey)
                about! what a wonderful thought for a new start-up. the sect of witnesses of Saint Lumen will be delighted, grace for the idea)))

              • Alexey

                If the exposure meter measures illumination, then it does not depend on the size of the frame.

        • Alexey

          (this is another Alexey)
          “The objections of the rest of the participants in the discussion have no arguments. Let it be as they please in their universe. "
          this nonsense is difficult to comment on as well.
          I gave a description of the simplest experience that no one has ever been able to refute.
          I don’t want to go into theory in principle, because it will be too long.
          and yes, I also developed my cameras, for specials. applications, so I practically know how everything should work.

          • Victor

            I think that Alexey, who is “original”))) is just trying to say something of his own, but no one understands him.

            • Alexey

              (this is another Alexey)
              I have often met and still meet, even among professional developers, people who piously believe in their delusions.
              and that experiment, with two cameras, showed many times, including to adherents of “Saint Lumen” and “Magic of the Full Frame”. they saw the result, but all that they could squeeze out of themselves was - “this cannot be, because it can never be,” they say, I wound something in the cameras.

              • Yaroslav

                And what does the result have to do with it?) The question of ff is primarily in the comfort of work, the presence of glasses and a more plastic image during processing. The final result can be customized.

              • BB

                Or another experiment is possible: an FF camera, which has a crop camera mode)) And everything falls into place: the exposure does not change from 'cropping' the frame

      • Tryamer

        Jupiter 36 with a converter on the crop for photography used all spring. 300mm Tair is small, and f / 9 with a converter is dark and of poor quality. Everything else was too expensive.
        And at the expense of a non-native format for lenses: 40 / 4.5 from the shift, and pentacon 135 / 2.8, require the camera to set the aperture 2.8 and 2.2, respectively. That the exposure was normal. Maybe because of the fall in illumination to the edges in the native format.
        This is because maybe a lens with an FF on a medium format will give the opposite effect.

        • Rodion

          Apparently you have a very good specimen of Jupiter. Mine was too soapy and without a converter ... Their assembly is bad - that's why the quality suffers.
          The lens itself is inconvenient, and the focus ring is too close to the camera. The mass is poorly distributed.

          • Tryamer

            Probably lucky. He is also from Inv. number painted with paint, and, in theory, should be loosened due to active use, but no. The distribution of masses does not interfere in any way, the center is almost on the M42-88 ring. If with a converter, then on it. Maybe it's more convenient for a left-hander.

      • koba

        The GFX 50R can already be purchased for $ 2700, which is even less than some new full-frame cameras, and also ... Nobody dared to dream about such a price for a camera with an enlarged matrix. For portraitists and studio photographers, this is a real find.

        • Arkady Shapoval

          Pentax 645D now and for 2000 can be found. Medium format to the masses!

    • Yaroslav

      It is worth it, of course, if the lens covers an area of ​​more than 36x24 mi

  • B. R. P.

    For example, Temka, where Mr. Mironov and some other years. amuse themselves not only with their native optics: https://fujiclub.pro/forum/threads/sf-fujifilm-gfx-50s-50r-i-100.4248/

  • Alexey

    Arkady, in the heading of the article - “sensors with a crop fator” - he missed the letter K.

    • Arkady Shapoval

      Fixed

      • Alexey

        and also, right after the picture - “I like simple and understandable ...” - I like

        • Arkady Shapoval

          fixed

  • Pavel helios

    The depth of field will not change in any way here, there is no need to mislead people

  • Pavel helios

    DOF will not change in any way, do not mislead people

    • Alexey

      Arkady and I have argued on this topic more than once. DOF, of course, just won't change IF you shoot from the same distance.
      but about the change in depth of field, Arkady meant that if you shoot the same object with the same lens at the same aperture position, full frame and crop, then to get the same crop on the crop camera you will have to move away the crop factor is one time further, which, essno, will lead to an increase in depth of field.
      Of course, all this is far-fetched, but it has its own logic (with which I disagree).

      • Arkady Shapoval

        Then let Pavel Helios put forward this claim to many big sites dedicated to photography, which recalculate the aperture in terms of depth of field depending on the frame size (equivalent F-number). It's just a generally accepted method, just not as common as EGF. In the same way, it is argued that FR does not change, confusing EGF with FR.

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