Metabones Speed Booster Issues - Minolta MD->Fuji X

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xaprb Junior Member • Posts: 29
Metabones Speed Booster Issues - Minolta MD->Fuji X

I’ve been testing various focal reducers for adapting vintage full frame lenses to my Fujifilm APS-C camera. Surprisingly, I neglected to test my Minolta lenses for infinity focus: I was doing all close-range work. When I tested infinity focus, I quickly found obvious flaws with the Metabones Speed Booster Ultra.

My Minolta MC Rokkor PF 55mm 1:1.7 – MC II lens won’t infinity focus because the rear of the lens runs into the glass of the Metabones. It’ll only focus to about 3 meters. It needs about a millimeter more travel to focus at infinity.

My Minolta MD Rokkor 85mm 1:2 won’t infinity focus although it doesn’t run into the glass. It only focuses to about 250 meters.

Both lenses focus past infinity with a standard glassless adapter. I have several adapters of different brands and they all let the lens focus past infinity. So it doesn’t appear to be the lens’s fault. These are the only two Minolta lenses I have at the moment.

I bought an $89 Pixco focal reducer, which I have heard is just a rebranded RJ product. It works great. Both lenses focus past infinity just as they do with a glassless adapter, again confirming that the defect appears to be the Metabones’s optics. Neither lens runs out of space with this focal reducer. I haven’t tested the RJ focal reducer thoroughly for image quality but a few quick tests through the viewfinder with the focus magnifier looked excellent. That’s a subject for another post when I have time to test properly.

One problem Metabones does document is mechanical incompatibility with some Minolta lenses’ aperture control pin. They state that a list of 10 or so lenses won’t fit onto the adapter because the pin protrudes more than 10.5mm from the flange. I measured my lenses’ protrusion at 11mm with a caliper, although they were not on the list of incompatible lenses. I trimmed them to 10.5mm and they still interfered with the focal reducer. I had to trim them basically flush with the flange to fix it, far shorter than 10.5mm.

I’m returning the Metabones. I can’t see anything obviously wrong with it—it doesn’t look like it’s not fully assembled, for example. I tried to post a review on B&H mentioning these problems but they haven’t posted it yet. Anyone else seen similar issues?

 xaprb's gear list:xaprb's gear list
Olympus PEN-F Fujifilm X-S10 Fujifilm XF 23mm F1.4 R Olympus M.Zuiko Digital ED 14-42mm F3.5-5.6 EZ Fujifilm XF 50-140mm F2.8 +5 more
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