Fotodiox Vizelex ND Throttle - The Variable ND in a Lens Adapter! Quick Review

The amazing team at Fotodiox and I walked through the issues I was having and we have identified it as being a defective copy that I have. They sampled the same lenses and did not find the issues I was having. It is possible that the chrome on one of the parts was too thick or maybe a machining error. Regardless. Fotodiox is sending out a new copy and I will hopefully put up a new review in short order.

Thanks the wicked team at Fotodiox, and Bohus who personally called to discuss this.

I'm super stoked to put this through the paces and talk more about it.

I've identified an issue with the adapter that for at least one of my lenses does not focus to infinity. It also affects all other lenses in where the focus distance is completely incorrect (where 10 feet is normal but with adapter it shows it at 4 feet). I suspect that this problem is probably a minor issue where the adapter thickness is too thick by .5 mm. I've contacted Fotodiox and hope to hear back from them about this issue. For now this review will be redacted until further notice.

I apologize to my readers about jumping onto this without a thorough test (just very excited by this). I hope it's a simple issue that should be resolved with a thinner profile adapter.

Mounted onto the Sony A7 with the Samyang 14mm
One of the problem lenses at the moment with no ability
to focus to infinity.


  1. Thanks for the review Terrance! The folks at Fotodiox have been really excited to see all of the interest in the ND Throttle. We're all interested in hearing more about how you like the Throttle the more you use it.

    BTW the polarization error you're mentioning has to do with have the lens set wide - like around a 25mm. That's when you'll see the error - I show it in one of the videos. It's easy to see on a zoom. The effect can look fine until you zoom out, and then you see the cross pattern.

    Oh and thanks for the comment about our quality going up. We feel we've always had a good product, but we have been upping our game even more over the past few years. Thanks for noticing!

    Thanks again for the review!

    1. Bohus, I had to redact this review until I get some contact back from your support team. Very excited by this adapter, however the primary lens I purchased this for, does not focus to infinity. Other lenses are also exhibiting issues as well.

  2. Using back filters + keeping infinity requires pushing forward the lens at around x0.3 to x0.5 of the filter's thickness. More so on short focal lengths \ wide lenses. Mount shims, metal or improvised paper, are a common solution.

    1. Fotodiox is expecting a newly designed adapter soon. Part of the problem that I identified was in the filter elements specifically the front element of the two element design. The flaw has been identified and will be corrected in an upcoming update.

  3. Has this even been fixed? I did not find anything about this product other than this review.
    Maybe it is just another 'nice concept but bad execution' cases.

    1. Bohus might be better to comment on this. I have been helping them at Fotodiox identify the problem which they have corrected a manufacturing defect and should be shipping a new version sometime very soon. When that arrives, I'm not certain, but I do know that they are committed to ensuring that it is corrected.


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