NEX Speed Booster’ish Focal Reducer Adapter

Sony NEX shooters rejoiced when Metabones announced a Speed Booster adapter that offered a Full Frame look on the NEX cameras, but also increased the F-Stop of the lens attached. Check out the quick review from about the Metabones Speed Booster.

So how does this work? In short, it's similar to a Telephoto Extension adapter that multiplies your lenses focal length. The reason why it's able to perform this same technique in 'reverse', is because it is using a lens designed for Full Frame cams, but is directing the image to a much smaller sensor (like the NEX). The Metabones supports electronic functions like Image Stabilization and aperture can be controlled directly from the Sony NEX cameras buttons and dials, but price ranges from $450-$600 dollars (found here).

Recently another Speed Booster'ish Focal Reduction adapter has been released, but it offers no electronic communication. This one is designed for Nikon manual lenses with manual aperture controls to mount to your Sony NEX cameras (metabones does not currently offer Nikon to NEX). You can use this to achieve a Full Frame look from of your Rokinon (Nikon mount) lenses as well. At less than half the price of the Metabones, this adapter is being listed at $198 via eBay (click here)

Not MetaBones Focal Reducer Speed BoosterSpeed Booster Focal Reducer
find-price-button Focal Reducer Speed Booster Nikon to Sony NEX

When is someone going to make one for the BlackMagic or MicroFour Thirds?

22 thoughts on “NEX Speed Booster’ish Focal Reducer Adapter

  1. Darren

    Also, FWIW, and it's not evident in the pictures provided, there is marked vignetting even in the Metabones speedbooster on the 100mm L Macro

  2. FYI, I bought this at $196 and have to say that the construction is very solid. Like 150grams of solid metal and glass solid.
    It's branded "Zhongyi" and can be had in China for HALF the price via Taobao, sold as 中一学 brand, apparently a company in northeastern China that makes lenses. The picture quality is, without having a way to scientifically test, pretty damned good. Check the link above.

  3. Bartek

    my mistake wanted to say EF to EF-M. That would allow you to use your FF lenses on crop sensor with all the benefits of metabones adapter. that would be just great!

  4. John

    I would buy this if it had a tripod mount (similar to the collar found on larger room lens). Don't think my nex 5 can support the weight of my rokinon lens...

  5. chandler

    its possible that this a regular adapter with glass from a telescope focal reducer. not sure if that is a bad thing or not. telescope focal reducers range in price from 26 - 379 on ebay.

  6. Austin

    Just picked up a nex 5n and I work will all nikon lens, only one of them is a G lens so would be tempted to get this, but this just seems like one of those things I wouldn't trust a knock off product on till I saw a few good reviews.

  7. MN

    Seems plenty viable for the FS-700. I shoot manual focus anyway, so the basic adapter would work fine for me.

  8. marklondon

    This is great. I have a full set of Roks. Perfect for when i hire an FS700.
    The lead time between the original and the cheap copy keeps shrinking!

  9. J Toha

    What about the optics within? I understand Metabones enlisted the help of a renowned optical manufacturer so the glass is a high-quality one that will minimize any reduction in image quality. Now I'm not sure about this ebay version...

  10. Jerry also

    @Emm The designer cites the mirror as the first obstacle -- the rear of the adapter needs that space. But it will work with APS-C sensors on mirrorless cameras, I believe.

  11. VisX

    Until there are positive reviews, I am not comfortable to buy this cheaper adapter. From the external appearance of the item, I found that:

    - it only has 3 screws on the lens-side mount. More screws usually means less likely the mounting ring will become loose. Usually more expensive adapters have 4 or more screws.

    - no brand name is mentioned

    - there is not single letter marking, eg: Nikon -> NEX, Focal Reducer, etc. If they skip this because of cost constraint, what other corners they have cut which you can't see?

  12. Emm

    Post author

    @Grant - No it won't because the Canon DSLR sensors are large. This is taking a lens designed for a large sensor, and making it work correctly with cameras that have a tiny sensor. With this type of design, you can step down, but you can't step up.

  13. Jerry also

    Let me add that the adapter's preservation of at least the aperture contact point is essential with EF lenses because these lack external aperture rings. The only way to change or even ascertain exposure with a non-Canon body is to bicycle the lens back to a Canon body every time; not practical.

    This jail-breaking of EF lenses that Metabones had announced could hardly have been met with rejoicing at Canon HQ and I can't help wondering if the EOS gang didn't have something to do with this new and open-ended delay. First the BMCC, now this...

  14. Jerry also

    For readers saying to themselves, "This is too good to be true!" -- the designer explains the engineering principles involved here:

    This reverse teleconverter promises not only to solve or at least diminish the crop factor problem on all three Black Magic cameras, but will make a huge variety of full frame lenses work with any mirrorless camera body, regardless of mount. Once all the promised versions of the adapter become available, that is.

    Alas the demon of delay has now reared his or her monstrous head. Metabones promised the MFT version "soon" at the initial announcement back in January; now this has been pushed back. Here are the links; from Meta (look under "When will M4/3 cameras be supported?"

    and from, with their explanation: ... t-delayed/

    The worst part for some of us is that the EF-to-EF version, which would would widen and otherwise improve EF lenses on the BMCCs while preserving electronic connections, has been delayed indefinitely. Why o why is this happening?!

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