Viltrox EF-M2 Adaptor Tested!

It was only a couple of weeks ago that the Viltrox 0.71x smart m43 focal reducer became widely available through eBay for the stunning introductory price of only $159 including shipping from HK to North America (Toronto for me).  It follows the optical prescription of the original Metabones Speedbooster with  4 lenses in 4 groups and full EXIF/AF support for Canon lenses.    Given that the current Metabones T Speedbooster Ultra retails for $649, this seems like an incredible deal … but is it any good?   I’ve had the misfortune of buying a Chinese made smart adaptor that was so poorly machined that it was extremely difficult to mount and never worked, likely because the electrical contacts did not line up correctly.

Things were off to a good start.  I received the adaptor in under 10 days during the peak of the Christmas rush!!!!  The packaging was very good and clearly a nod to Metabones.  Also included was the correct sized hex wrench and miniature Phillips head screwdriver.

Unpacking the Viltrox EF-M2

And it was nicely machined, slipped onto all my m43 bodies without stress and with a positive lock.  Unfortunately the AF does not work reliably with the E-M1 or E-M1.2 but that was disclosed by the company from the onset.  It apparently works with the E-M5, E-M10 and GH4/5  so likely not talking well with the phase detect focus system.  It also does not work at all with the Yi M1 or the Z Camera E1.  I have faith that  a new firmware version will be available to make it work with the E-M1 family.

My test camera is the EPL-5 and the AF was quick and accurate much like what I experienced with the Kipon or Metabones adaptors that I have.  There was no real need to quantify the AF speed as I have in past tests because Viltrox AF is simply more than fast enough for real world applications and there is no hunting.  I did want to test the optics of the focal reducer and for that I performed my usual MTF tests as described ad nauseum in past articles.  Going in a clockwise direction from the upper left:  Kipon adaptor (with Canon 200mm f/2.8 L series prime), Metabones Speedbooster S, Metabones T Speedbooster Ultra, and Viltrox EF-M2.  Red curves are MTF10 and green curves are MTF30.

MTF curves for Kipon, Metabones & Viltrox smart adaptors

The MTF curves do appear to demonstrate that the Viltrox has the sharpest centers with a rapid falloff halfway across the frame but the undeniable take home message is that it is as good as the Metabones.  For a whole lot less.  In fact, the current eBay listing shows a price change already to $200 USD so demand appears to be healthy.   I heartily recommend that this little trinket find its way to your favourite m43 user’s stocking.

Addendum Dec 16/17.

Even the family pet is intrigued by the new Viltrox adaptor and wanted to check it out for himself.  Fortunately he soon grew bored of it after realizing it was inedible and allowed himself to be photographed.OLYMPUS DIGITAL CAMERA

If you click on the image, you can inspect it at 100%.

The Viltrox adaptor was used on the left, and the Metabones T Speedbooster Ultra on the right.

Addendum Dec 24, 2017.

In case it’s not clear that the optical sharpness of the Viltrox is very similar to the Metabones T Speedbooster Ultra, I’ve included the ISO test chart and 200% center crops of each for study.

Metabones (left) and Viltrox (right), click to see in full original resolution



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  1. Interesting and valuable stuff, thanks! Just one thing, “rapid falloff halfway across the frame” should be “halfway to the side from center” or something like that. The center IS halfway across the frame 😉

    Liked by 1 person

  2. Kipon adapter /without glass/ works badly with 400/5.6L – barely acquires focus after numerous attempts with both E-M1 and 2 but the adapter works ok with shorter Canon lenses.
    I suspect there is a general problem with long lenses as regards EF-MFT adapters(?)


    1. Both the Kipon and Metabones work fine on Sigma 50-500 and Tamron 200-600 lenses but poorly on the Canon 400/5.6L.

      I think it has much more to do with which generation of AF. The 400/5.6 is an older generation lens.


  3. Jim, thanks for doing this test. I have no interest in MTF curves – just whether the adaptor is well-built and performs well. I bought one after reading your blog. On both counts it wins. It’s very well-made, seems to be as sharp as a Metabones and the AF, IS and iris control all work properly. For £148 – not bad at all. What a shame about “Boris” and the other aggressive f***wits on M43 rumours. From me – THANK YOU 🙂

    Liked by 1 person

  4. Thanks, you sold me on this adapter. Appreciate all the help you are providing the community regarding speed boosters/adaptation! On a sidenote (have not looked at all your blog entries yet, sorry!) – do you have a recommendation on a straight up smart adapter? The Metabones one is probably great, but as usual, very expensive – and no optics either.


    1. Thanks Tom, My first smart adaptor without optics was the Kipon and it works but there seems to have been no firmware updates for quite some time. I found the Metabones focuses faster and less hunting with some EOS lenses and they always improve their firmware.


  5. Great review, which reinforces my personal experiences.

    I don’t have any Canon lenses, but have a number of the better Olympus OM lenses, and due to Canon’s tall register distance, OM lenses can be used with Canon adapters with a thin and inexpensive ring adapter.

    The original EF-M2 would not work without an electronic lens attached. Viltrox quickly responded to my complaint, telling me to tape over the contacts! Which I did, but it seems kludgey. I’ve been hoping a firmware update would allow me to remove the tape before it became one with the adapter, but haven’t made it a priority to update, since I only use it as a dumb adapter.

    Then, the “II” version of this adapter came out, and by careful shopping, I got one for just US$116. It appears to equal the original version optically, but YAY! No tape required! It works fine with the EF —> OM dumb adapter.

    I see that @Emil Pozar asked that you test the adapter with a different lens, and you responded that you weren’t convinced of the need. My perception (not backed by data) is that the Metabones Speedbooster Ultra (OM version) out-performs either Viltrox EF-M2 on wide angle lenses, but that, as you discovered, they are about par on longer lenses. When paired with the OM 21mm ƒ/2.0, either Viltrox has more chromatic aberration than the Metabones in the edges and corners, which doesn’t work for me, since I use that for astrophotography (equivalent 15mm ƒ/1.4).

    One other difference worth pointing out for the aesthetically-obsessed: the Metabones is a much more integrated-looking adapter, at least for OM lenses. Because the Canon EF basic lens diameter is larger, the diminutive OM lenses look like they have a beer belly when mounted on the Viltrox. And the Metabones doesn’t have strange little bits (unneeded, in my case) like switches and USB ports hanging off the sides.

    I also have the Kipon Baveys OM focal reducer, and also find that it does not do very well with wide angle lenses. Even with long telephotos, it tends to add vignetting, perhaps partly due to IBIS, although I have not noticed it with the Metabones or Viltrox focal reducers.

    Bottom line: I could be happy with just the Viltrox Mount Adapter EF-M2 II, if I hadn’t already scored the Metabones Speedbooster Ultra (OM) — which never goes on sale — on a rare eBay “20% off anything” sale.


  6. My experience with the Viltrox EF-M2 speedbooster is that on lenses 135mm and shorter, (testing on astro targets), there is distortion introduced in the form of radial streaking of the stars towards the edges of frame. The lenses tested were Samyang 135/2, Olympus OM 100/2.0, Samyang XP 35/1.4.
    No problems with longer lenses eg Nikon 300/2.8, Zeiss Mirotar 500/8.


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