Zhongyi Lens Turbo II: Compatibility and mounting problems

Zhongyi Lens Turbo II for Minolta MC/MDAfter using the Zhongyi Lens Turbo II for a while, there are some quirks and restrictions popping up. The optics of the Lens Turbo (LT) are very good and the mechanics look solid, too. But not all lenses are compatible and mounting the LT on the camera can be a bit fiddly – it’s always tricky to get it to lock. In contrast to a native lenses, the distinct “click”-noise when mounting is missing as you don’t turn the whole adapter, but only the locking flange. In any case, the adapter would still rotate easily when mounted. As it turns out, there is a reason for that…



There’s some lenses, which can not be properly mounted on the Lens Turbo because the aperture pin is blocked and others, where the rear lens element can collide with the LT optics. Hillyard Photography is maintaining a list of over 80 lenses with various mounts, which have been tested for compatibility with the LT II. There is also an active Flickr dicussion related to this list, where new findings are usually published first.

In case of the LT II for Minolta MC/MD, lenses where the back element protrudes more than 3 mm from the back of the mount when focused to infinity can collide with the Lens Turbo optics and shouldn’t be used. If you can mount the lens, but the aperture is stuck open or you can not fully mount it but the glass does not collide,  you can most likely fix the problem by filing down the aperture pin of your lens by approx. 1 mm. Although I don’t like the idea of tampering with my lenses in this way, it’s a viable solution and does not impede the functionality of the lens. If you do this, just be careful with the metal shavings and make sure the lens is completely clean of them before mounting it on your camera. The shavings may otherwise lead to shorts or mechanical damage. This is especially important on cameras offering in-body image stabilization (IBIS) like the A7II, which use very fine electromagnetic solenoids to position the sensor that will magically attract all metal flying around in the mount.

If you are having problems focusing to infinity even with your compatible lenses, there might be an issue with the optical assembly in your Lens Turbo. Luckily, one adventurous user took apart his LT and documented how to adjust infinity focus. In short: You can screw the whole optic assembly in or out after removing the three screws on the back and loosening some glued parts. Have a look at the thread linked above for detailed instructions.


Mounting / Locking problem

Unmodified Lens Turbo II, orange reactagle marks chamfered mounting pin boreAs mentioned, the Lens Turbo has a very nice mechanical construction, but mounting it on the camera does not give you the same feedback when locking as mounting a native lens does. And it always tended to rotate while mounting or dismounting lenses. I originally thought the chamfering of the bore for the locking pin (see image on the left) was responsible and that the pin would just be pushed in inadvertently. As it turns out, that was not the reason.

Looking at the mounted LT on the A6000 of a friend showed, that the tab on the LT protecting the lens release button did not only protect it from accidental actuation, but also slightly pressed it down all the time. This resulted in the locking pin being slightly retracted when the LT was mounted on camera, which, in turn, made it very easy to just turn the Turbo (and scratch the plasic inside the mount) although the lock was seemingly “engaged”.

Modified Lens Turbo II, detail of filed-down partModified Lens Turbo II, orange rectangle marks filed-down partIt can be argued, whether it was a design choice of the manufacturer not to rely on the locking system. In my opinion, this is a bit of a half-baked solution. A friend of mine agreed and decided to modify his LT accordingly. He used a file to shave off about 0.5 mm from the backside of the tab protecting the lens release button (see images on the right). The result looks nicely machined and had the desired effect: The Lens Turbo now mounts with the locking pin fully engaging and doesn’t twist easily anymore while mounting lenses. If you don’t fit the Turbo perfectly while mounting it to the camera and have to twist slightly to align it, the satisfactory “click” noise will be more pronounced, too.

All in all, this turned out to be an easy fix and really improves the confidence in the locking mechanism while working with the LT.


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7 thoughts on “Zhongyi Lens Turbo II: Compatibility and mounting problems

  • Brian Patterson

    Great info – I will be test shooting with my 11 Takumars and several Mir, Helios, Minolta optics in my collection this weekend with the Turbo Lens II. Three of the listed Takumar lenses and both my 44-2 and 44M Helios mount up with no problems for me. But I have one Takumar not listed that binds up the aperture ring and does not seat fully. No problem – I’ll grind down the flat aperture tab and hopefully relieve that issue, along with the lock tab on the adapter to lock it.

  • Robert Belgrad

    For anyone who might be helped by it, I would recommend purchasing a 0.8mm flat-head precision screwdriver to carry along with your LT2.

    The versions of the adapter I own (M42-M43 and M42-FX) both share a design / manufacturing ‘quirk’, and the body of the adapter is affixed to the inner threads by three tiny set-screws. These screws hold the outer and inner parts of the adapter together through COMPRESSION ONLY, and eventually they loosen. This is particularly true of the M42 versions, as tightening and loosening screw-mount lenses puts additional strain on the set-screws.

    Carrying a 0.8mm flat-head screwdriver will allow you to re-tighten the set screws periodically, otherwise you run into 2 problems:
    1. The inner threads rotate, so when fully attached, your lens’ markings are not aligned properly (i.e. upward).
    2. The adapter will cope completely apart, and your lens will hit the ground.

    Just wanted to spare others learning this the hard way.

  • Kaylon

    THANK YOU SO MUCH FOR THIS TIP!!! I’ve been getting really irritated with the rotating mount issue on my lens turbo. I love every other damn thing about the adapter but this one issue has been so annoying. Thanks!

  • Alok Sinha

    I am fairly new to this focal reducer world & have never tried one. Just a noob question, Won’t adjusting the rear lens element on a focal reducer avoid the Rear Element Collision of lenses which have their rear element hit by the front element of focal reducer? The counter clockwise rotation on Viltrox focal reducer seems to make element on the lens mount side go deeper simultaneously with the rear end protruding more towards the sensor, very similar to infinity focus adjustment. Won’t it just provide infinity focus on such REC lenses with a shifted focus meter scale ?

    • Benjamin Post author

      Hi Alok,

      good question. I had to look it up and came about this: https://www.dpreview.com/forums/thread/3608293

      As fas as I understand it, screwing the optical group of the Lens Turbo in or out changes infinity focus. If it was correct before – when lens elements were colliding – you would then need to also adjust the infinity focus on that lens. I assume that this would cause the elements to collide again and the only thing that effectively changes would be the FOV. I’m not sure, though.


  • Conrado Bravo

    I have used this adapter to my Tamron SP 35-210mm lens FD-NEX. It works okay manually focusing the lens. But here’s the ultimate problem; you cannot disengage/uncouple or remove the adapter from the lens meaning, it got stuck with the lens forever.

    Now, If someone/somebody here knows how to uncouple/disengage this adapter from the lens please inform me or let me know. Thank you in advance.