Mixed results with Alpha mount adapter

Discussion in 'Adapted Lenses' started by ajm80031, Aug 5, 2013.

  1. ajm80031

    ajm80031 TalkEmount Regular

    Jul 16, 2013
    I purchased a Rainbow Imaging adapter to be able to use my legacy Minolta A-mount lenses on my NEX-6. I'm finding I have mixed success with the adapter. My 50mm f/1.7 lens works great with it -- I'm able to focus reliably, and when I achieve focus the distance scale on the lens reads about what I'd expect. However, I can't get my 35-70mm to focus on anything other than about 8 ft away, and when it does focus the distance scale reads less than half of what the actual distance to the subject is.

    When placed on my old Konica-Minolta 7D, the 35-70mm can focus as close as about 3ft away and the focus distance matches the scale.

    Since the 50mm lens works just fine, it appears that the lens-flange-to-sensor distance of the adapter is correct. Is this a common problem with adapters (work for some lenses, not for others) or is there something I should be looking at? I've removed and reattached the lens (and adapter) multiple times to make sure it's seated properly.

    One nice thing is that, with the lenses that do work, the NEX-6's viewfinder is sharp enough that I can get the focus pretty close even without the focus assist features (enlarged view and focus peaking) although those certainly help with the fine-tuning.
  2. addieleman

    addieleman Passionate amateur

    Nov 13, 2012
    Real Name:
    Ad Dieleman
    You say for the 50mm lens "when I achieve focus the distance scale on the lens reads about what I'd expect". Maybe the adapter is just a tad long which is obviously not a big deal for the 50mm with its conventional focussing (the whole lens group moving back and forth), but the 35-70mm could be much more affected by that. The zoom lens focusses differently, not moving the whole lens group. Just guessing. When I receive an adapter (the cheapo Chinese ones) the first thing I do is tighten the screws on the MD bayonet mount, they're always loose. And there may be grit between the chrome ring and adapter housing; I sometimes remove the screws and move the ring back and forth to remove grit and burrs, this has helped in one occasion to attain infinity focussing with a sample.
  3. xXx1

    xXx1 TalkEmount All-Pro

    Jan 15, 2013
    Most cheap adapters are a bit too short (one of my PK->Sony E is 0.3 mm short) but this don't affect but lenses with very short focal length. I really noticed with Samyang 14mm. With 35mm lens there should be no problems. My Minolta 35-70 works very well with cheap MD->Sony E adapter.