Metabones Speed Booster Ultra review – Part II – Canon EF 50/1.2 L

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35 Responses

  1. Martin says:

    Very interesting review, Viktor.
    I decided to skip the focal-reducer craze, and simply invested the money in full-frame glass (e.g. 55/1,8) and the A7R. I can’t say that I regret the decision, but I can certainly see the merits of having an APS-C system, with a focal reducer for when you need it.
    Nice work, as always.

  2. Thanks Martin. One if the advantages of focal reducer on APS-C in combination with smart adapter, is that you can have two lenses in one. Such a EF 50/1.2L can serve as nice portrait 75/1.2 and 53.5/0.95 FOV and DOF FF equivalents. There are many 24/2 lenses which with Focal Reducer would give 26/1.4 and with normal adapter – 36/2. That makes them interesting alternative in terms of budget and space in the bag. For me, they are also interesting optical chellenge and I am honestly amazed what Mr Caldwell did with the Ultra.

  3. Juan Carracedo says:

    Hi, thank you for the review. The first on the net! I appreciate a lot the work you do, it is very helpful.

    Zone “C” in picture seems to be wrong. I see much better sharpness on LensTurbo II image than the A7 + Bare lens one. How is it possible??

    Which are the next lenses you are going to Test on the SB II Ultra? Is it possible for you to test a vintage 28mm lens? If not, any 28mm would help too.


    • Juan Carracedo says:

      The web link does not appear in my last message, the picture I was talking about is the test chart results wide open (ISO12333_090.jpg)



      • Andew says:

        There must be some field curvature distortion because the adapter shots are all sharper at the side than the original on the A7 as noted above.However I suspect focus may have been off on the A7 shot. Enough that it made section D look sharper and pushed D out of focus. It would be interesting to test this on a maco lens with good flatness of field.

        • Hi Andrew, there is certainly pronounced field curvature with the bare Canon EF 50/1.2L, and applying focal reducing optical correction is not linear as I wrote above. Imagine to have curved mirror that you are trying to correct with counter shaped mirror while keeping same FOV but from closer distance. Different part of the mirror image will be distorted after such correction.
          I can assure you that focus is not off (selected from more than 15 frames), but focus was placed at the center of the image.


      • Hi Juan and thanks for comment,
        Optical correction that focal reducer does is certainly not linear and thus some parts of the image are better corrected than others. While better performance should be more visible near the center of the frame, with just slight deviation in centering of the lens or adapter, such results are possible. The intention here however wasn’t really to compete with bare lens on FF, that set of images serves rather as the reference.
        If nothing, that is another proof that not every adapter degrade IQ across the frame 🙂


  4. michal says:

    hi, thank you for your review. its pretty interesting but i don’t agree with LT mark II- mine copy doesn’t wobble at all. it has to but attached on NEX that way because of internal reflection- as you can see LT II has square exit pupil. if it was circular like metabones there will not be any problem with mounting. i think LT II is a pretty good value for money. the best solution for old manual focus lenses on NEX body. have a nice day.

    • Hi Michal and thank you for the comment. It is good to know that you don’t have a problem with wobbling. Sample variation? Those guys in ZhongYi ignored me completely, I asked them for the test sample but they didn’t even reply, so I had to buy my copy and maybe I got dud. I don’t quite understand how the way of mounting helps with inner reflectiones, so if you find time, could you please explain it a bit better.
      LTII is a solid performer and great value, but for Canon EF lens users, Metabones is definitely better option.

  5. andres paz says:

    Should be interestant to be a full person foto of the SB 50 1.2L combo, just to see how renders and if gets that noctilux look.



  6. Yaw A. says:

    Thanks so much for this. Quick question. How do you think this new SB compares to a full blown FX body? I am trying to decide between the A6000 and possibly an A7R. I do plan on getting 4K monitors so the extra resolution would be somewhat visible, but 24 MP is plenty and the A6000 only really gives something up to the A7R in resolution and base ISO performance.

    • Hi Yaw A.,
      The upper cropped images compare what you are asking for – A7 with Smart adapter and A6000 with both Speed Booster (old and new) and Lens Turbo II. In my hummble opinion, differences are rather small, surely much smaller than producer wants us to believe, between FF and APS-C (recent technology).
      Main difference will be – AF with SB vs native FF lens, if you don’t want to go with LA-EA4 and Sony A mount SSM lenses. Slightly better low light performance and slightly larger dynamic range.
      Sony A7r has visible increase of resolution, compared to Sony A7, but there is very real shutter shock problem with that camera, which causes decrease of resolution with many lenses at pixel level (induced blur).
      I would stick with A6000, small but very capable camera and wait what future will bring. Just my 2c.


  7. Ivan says:

    Thank you for your review! There is a scarcity of information about focal reducers in internet and your review completely dots the i’s and cross the t’s. I think LT II is a great value for its money and it is very smart solution for mirrorless APS-C owners who like manual optics. But only one thing frightens me- very strange bokeh. In the last images comparison (before conclusion) it looks like focal reducers completely destroy the beauty of lens bokeh. Is it true or not?

    • Hi Ivan and thank you for all kind words.
      When you consider appearance of the bokeh you should always think of both – quality and quantity. In this case, there is little a difference in magnification (or better to say field of view) between bare lens on FF and lens on SB or LT on APS-C sensor. Because of very short distance to the subject, this otherwise insignificant difference, can create visibly different bokeh. In fact – it’s 50mm FOV vs 53,25 (SB) vs 54,45 (LT) (approx, because APS-C is not exactly 1,5x smaller).
      What we see in above mentioned images is related partially to those FOV differences (and resulting DOF differences) and slightly to reduced micro contrast, caused by APS-C vs FF sensor (characteristics) and little degradation of the focal reducers themselves.
      In other words – I don’t think that focal reducers destroy bokeh, nor that they have huge influence on its quality. Difference in quantity is of course related to the change of a field of view at the first place.

  8. phrenzy says:

    Do you think you would get better corner performance on a micro 4/3 body where the crop is greater and you’re essentially using the inside 2/3 of what an aps-c sensor would see? Are you essentially doing the suggested crop in camera?

  9. Hi Phrenzy,

    there are many opinions about FF lens performance on smaller sensors.

    With legacy lenses, we can usually agree that smaller sensor uses best part of the lens projection and thus in theory it should improve lens appearance.

    On the other hand, those lenses were designed for full frame sensors and some of them uses different aberrations on intention, in order to create more interesting rendering.

    Another thing to consider is a pixel density, which is higher with smaller sensors (usually), and this can increase visible differences in a rendered zones.

    Finally, there are lenses (lot of modern designs) which in order to improve corner smearing, involve wavy field curvature. That means that while corners are sharp, zone closer to the middle of the frame shows more smearing. (usually called zone C). When the image is cropped by smaller sensor, it might happen that it is cropped within zone C, which being also magnified (in percentage to the whole projection) can result in a perceived loss of corner sharpness in comparison to original rendering.

    Sensor topping and microlens design could also influence resulting image and therefore I don’t think that it is true in general that smaller sensor size – gets best out of the FF lens.

    However, in many cases that could be true.


  10. Kéno40 says:

    Hi thanks for that !
    And why not Minolta MD?
    Canon EOS to MD lens adapter exists, no?
    I din’t get your point here.

    • Hi Kéno40,
      Minolta SR mount (for Minolta MC/MD lenses) has flange distance (distance from the lens mount surface to the film (sensor plane) of 43,50mm and Canon EF has 44mm. In practice this means that you can’t use Minolta MD lenses on Canon EF mount (unless you fully modify lens mount) without so called corrective optics in order to achieve proper focus.

      While such adapters exist, resulting quality, especially in combination with another corrective optics of focal reducer, will be seriously compromised.

      In other words, mounting Minolta MD lens on Canon EF mount (with glass adapter) will degrade IQ.

      For the same reason, you can’t mount Canon FD lenses on Canon EF mount. If you have Minilta MD lenses, you should consider genuine Minolta MD to Sony E focal reducer.


  11. array16 says:

    Hi, thanks for the review, very interesting.
    Now I’m curious if any tested using Leica R lenses?

  12. Lewis Balentine says:

    Thank you for the EXCELLENT comparison. It is by far the best I have been able to find on these items.

    I have just ordered a A6000, 18-55 SAM DT lens and PK to NEX adapter. That lens is just so I would have at least one native lens (and it was dirt cheap). The real reason I ordered this body was because I have some archaic glass in the form of old school Pentax K mount manual prime lenses:

    0) pentax PK bellows unit
    1) asahi optical co. takumar 28mm f2.8
    2) pentax 50mm f1.4
    3) pentax 50mm f1.7 (several copies)
    4) original vivitar series 1 100mm f2.8 macro
    5) asahi optical co. takumar 135mm f2.5
    6) original vivitar series 1 200mm f3
    7) asahi optical co. takumar 500mm f4.5
    8) original vivitar series 1 600mm f8 solid cat (perk & elmer)
    9) russian MC MTO-11CA 1000mm F10 maksutov-cassegrain

    As a result of your review I have ordered the “Zhongyi Lens Turbo Adapters ver II for Sony E mount cameras” as well.

  13. Gloombug says:

    Great review. However I am still in doubt wether I should put a lens booster on my A6000. What is your subjective impression of the lens rendering and background separation? Fullframe and medium format seems to give in general a nicer blurring. You mention some lesser sharpness and flare. I wondered wether it is negated by the need to stop down. Giving one only the option to use a manual lens at its intended angle but not its dof. Native lenses seem in such case a more sensible choice given the coatings and modern lens design. On the other hand with Minolta MD’s at 35, 50, 135, 28-70 and 70-210mm in the cupboard a lens turbo might offer some unique rendering options. The MD 35mm f1.8 seems more gentile with highlights than the SEL35F18.

    • Hi Gloombug,
      I believe that buying Lens Turbo II is recently quite affordable and worth trying. I will suggest Metabones Ultra, mainly because of better optics and I would feel safer regarding possible reflections, but it is very expensive. You might invest in Turbo, see if you like results and if you experience increased flaring, you can always re-sell it with rather little loss and buy SpeedBooster Ultra.
      Full Frame has its advantages, but so does APS-C. If the rumors are true and we soon see A6100 with 36 Mpx APS-C, IBIS and 4K video, I would certainly consider such a camera as a very serious contender to A7 series.
      Just my 2c.

  14. Gloombug says:

    One of the reasons to buy into APS-C was the expectance of another stop or even two in the next 5 years. The technological capability is there, the commercially-viable production facilities however not. And for family shots I can easily push 6400 iso for a stop when doing 6MP exports. Other than for using an old lens in its original rendering, I find little reason to go full-frame. I do love the rendering of my occasional X700 and Rolleicord shots, though never far from home. If you make some bokeh and highlight comparisons for part III I’d be interested to see them :-). Thanks for your answer and review.

  15. Walter says:

    Hello Viktor. Great review. I have a question, maybe you can help me. I have the Blackmagic pocket and a few old M42 lenses and I use them with a simple M42-M43 adapter. I want to buy the Metabones Speedbooster for EF lenses (to make those lenses wider. In this way: M42 lens+M42 to EF adapter+MS EF+Blackmagic Pocket). But I want to preserve the soft vintage look. The MS will increase the sharpness and contrast of those lenses. Thanks.

    • Walter says:

      (The MS will increase the sharpness and contrast of those lenses?)

    • Hi Walter,
      I think that your plan will work. MS shouldn’t change lens character in sense of reducing spherical aberration or drastically improving micro contrast. However, MS for micro 4/3rd is not using as large portion of projection as MS for APS-C, so small portion of the prjection will end out of frame. Most lenses show non linear aberration characteristic toward edges, so it will depend on particular lens, how much of its “retro” projection will be preserved.
      Anyway, while MS improves mainly global contrast and change field curvature, it shouldn’t affect micro contrast, nor significantly improve monochromatic aberrations. Simply reduction of contrast in pp, should bring the vintage magic back…

  16. Gabrio says:

    thanks viktor for this extended test. Have you tried the viltrox speedbooster? how do you think it compares to the zhongy iq?

    • Hi Gabrio, unfortunately I didn’t tried Viltrox adapters nor speedbooster, so I can’t give you any relevant experience. You might want to visit DPreview “adapted lenses” forum and ask there. Cheers,

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    My last blog (wordpress) was hacked and I ended up losing months of
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  1. November 5, 2014

    […] Part II – IQ comparison with EF 50/1.2 L […]

  2. October 14, 2016

    […] of the Metabones equivalent, and most of the reviews I’ve read around the Internet have them on par with one another (that’s as long as you don’t mind losing the electronic […]

  3. March 20, 2017

    […] Turbo de segunda generación. Según vemos en una de las últimas reseñas (en esta se adapta un Canon EF 50mm f/1.2 a una Sony NEX) , la calidad ha mejorado mucho con respecto a los mediocres resultados del Lens Turbo primigenio. […]

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