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07-15-2017, 05:40 AM   #1
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Zhongyi Lens Turbo II any good?

Does anyone have first-hand experience with a Zhongyi Lens Turbo II 0.72x Speed Booster for Pentax K PK mount lens to Sony NEX E-mount?

Is it any good?

07-15-2017, 10:35 AM   #2
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I sent you a PM.
07-15-2017, 01:00 PM   #3
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I've had wonderful results with the M42-NEX version of this adapter. So much so, that I'm looking to acquire a PK-NEX version soon.
07-15-2017, 01:22 PM   #4
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I like mine a lot. Manual aperture control, but results are great.

07-15-2017, 03:57 PM   #5
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Thanks everyone. What focal length do you need to tell the camera the lens is? 1.42*[Actual focal length on the lens]?
07-15-2017, 05:03 PM   #6
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My A6000 does not have IBIS, so that setting does not apply to mine. To be honest, I'm not sure you would need to change from the actual FL. With crop, only the FOV is changing and not the magnification. A narrower FOV / Angle of View would not increase the amount of potential shake as the FL remains the same and the shake would be the same even on a full image non-cropped image. I'd leave the SR setting based on the actual FL of the lens -- not the cropped FOV.

Ex: You have a 50mm FL lens and have the shakes to the point where the lens moves to and fro 1mm side-to-side. Doesn't matter what the sensor crop is -- the lens is still only shaking 1mm side-to-side. The amount the lens is moving and the resulting blur does not change with the crop. Attach a 100mm telephoto lens and with the same 1mm shake, the blur is greater because the image maginifcation (zoom) over the 50mm. The SR system would need to compensate for that different FL. That's my highly unscientific opinion based n nothing other than my logic, although I can't vouch for its accuracy, it makes sense to me -- at least until someone can explain otherwise.

Also -- I think with your formula, you are assuming the SR accounts for the crop and it doesn't. With the Speedbooster, you would actually need to use the following formula:

(Actual Lens Focal Length x 1.46 sensor crop) x .72 for the Speedbooster

So for a 50mm FL lens, that means you would calculate an effective FL of 52.56mm. Since there is likely no such setting for SR, 50mm would be the closest. So you're right back where you started -- using the actual FL of the lens.

Last edited by ripper2860; 07-21-2017 at 03:29 PM.
07-21-2017, 02:25 PM   #7
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Thank you!

07-21-2017, 08:19 PM   #8
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Used canon to m43 version, was pretty darn good for the money.

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