Sony A7r with a Zhangyi Focal Reducer Speed Booster II Adapter

Discussion in 'Open Discussion' started by robfactory, Aug 26, 2014.

  1. robfactory

    robfactory TalkEmount Regular

    Aug 23, 2014
    Real Name:
    Ok, so after much deliberation, I bit the bullet and purchased a Minolta MD focal adapter for the A7R. One thing I noticed right away was the heavy vignette effect the adapter had, which was something not present on the non-focal adapter.
    I had to use the crop feature on the camera as not to get the vignette effect.
    My main question is... which is better? Having all 36mp without the Focal adapter or 24mp with the focal reducer II?
    Thanks for the help.
  2. WoodWorks

    WoodWorks Super Moderator

    Dec 12, 2012
    Ashland, OR, USA
    Real Name:
    Hm... somebody correct me if I'm wrong here, but isn't a Speed Booster adapter intended to be used on APS-C cameras, and should not be used on a full-frame camera like the A7R? The whole purpose of the Speed Booster is to refocus all the image circle of a full-frame lens onto an APS-C sensor, is it not? So you'd end up with some severe vignetting on a full-frame sensor.
  3. eno789

    eno789 TalkEmount Top Veteran

    Jan 1, 2012
    NoCal, USA
    Real Name:
    I don't think you can get 24MP in crop mode on A7r, more like 16MP.

    Of course you'll get heavy vignette with focal reducer on FF, it's supposed to work that way, covering just the crop part of the sensor.

    I personally would only use focal reducer on crop sensor, mainly for the field of view. It does make the lens a little faster too.
  4. shaolin95

    shaolin95 TalkEmount Top Veteran

    Jul 3, 2013
    I was thinking the same thing. Since all it does is "focus" the full frame to fit into the APS-C then I dont see how this will work on a FF unless you were using some Medium format lens or something..but maybe I am all wrong :D
  5. Poki

    Poki TalkEmount Hall of Famer

    Aug 30, 2011
    First, using a focal length reducer only works on crop sensor cameras, i.e. cameras with sensors smaller than the image circle of the lens you're using. You can't use a focal reducer on a full frame lens on a full frame sensor.

    Second, the quality of using the full frame lens on a full frame sensor will always be superior to using the same lens with the focal reducer on a smaller sensor, albeit might it only be slightly, depending on the quality of the focal reducer.
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  6. jai

    jai TalkEmount Top Veteran

    Feb 4, 2013
    Sorry to say, but I think you are better off with a dumb adapter on the A7r. Speed boosters are very much designed to be used with APSC.

    If you crop down and use a speed booster you may be able to shoot at a lower ISO. But you will be better off using the whole sensor and shooting at higher ISO, any extra noise will be less visible thanks to the extra resolution of the A7R.
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