Focus to infinity question

Discussion in 'Adapted Lenses' started by Sugarman, Jan 30, 2011.

  1. Sugarman

    Sugarman Mu-43 Regular

    Jan 21, 2011
    Dear Abby,

    in my adaptor shop thread, someone mentioned that some adaptors fall short of focus to infinity, some have it bang on, and others focus more than infinity.

    The first two I get, but "focus over or more than infinity"?

    I am not sure what that means and what effect it would have.

    I would really love someone to explain....


  2. photoSmart42

    photoSmart42 Mu-43 Top Veteran

    Feb 12, 2010
    San Diego, CA
    Focus past infinity has to do with focusing past the infinity mark on manual focus lenses. So essentially you set your manual focus lens to the infinity mark and expect everything most everything at a distance over 100ft or so to be in focus. With some adapters not controlling tolerances very well, they shave a bit too much off to ensure they at least get to infinity, but that makes it so that lenses set at the infinity mark focus beyond where they normally would on a perfect adapter. We're talking very minuscule distances here that have significant effects.

    Point in case - I was shooting an air show with my GH1 using my FD lenses. I also took along my F-1 film camera loaded with some Kodachrome. Photos taken at infinity with my GH1 - out of focus (slightly, but just enough to make those photos not what I wanted). Photos taken with the F-1 of similar scenes and distances - perfectly in focus.

    Yes, I could probably go through the trouble of shimming the adapter to get something closer to predictable focus using the lens marking. Frankly, I've already spent more time and money on making the cheap FD adapters work than I would have had I spent the money on the real thing to begin with. Back when I was unemployed, the trade made sense since I had time and not enough money. Now that I have a job, I'd buy a Novoflex adapter in a second. The only reason I don't is because I'm not sold on the m4/3 system just yet.
  3. Sugarman

    Sugarman Mu-43 Regular

    Jan 21, 2011
    Many thanks photoSmart... excellente explanation.