1. Reminder: Please use our affiliate links for holiday shopping!

Cameron Pentax K to m4/3 won't focus beyond 5 meters?

Discussion in 'Adapted Lenses' started by Curtox, Aug 30, 2013.

  1. Curtox

    Curtox Mu-43 Rookie

    18
    Jun 11, 2013
    Nova Scotia, Canada
    Hey, i'm really hoping I'm missing something obvious, but i've now tried two of these adapters purchased from Henry's (Canada), and got the same result from each adapter. Essentially, things seem fine as long as your focus point is roughly within the same room, but when you try to focus beyond 12 or 15 feet away, it's game over.
    I'm using it on a G3 w/ a Pentax 55mm F1.8:
    SMC Pentax 55mm F1.8 Reviews - K Prime Lenses - Pentax Lens Reviews & Lens Database

    And a Pentax M 28mm f3.5:
    SMC Pentax-M 28mm F3.5 Reviews - M Prime Lenses - Pentax Lens Reviews & Lens Database

    The issue is even more egregious with the 28mm, as it will not focus beyond 7 or 8 feet away :confused:. The results with the 55mm in particular are very promising for close range subjects.

    I am of course able to get the focus point to move further away by closing down the aperture, fairly significantly, to f16 and f22 (seems absurd to need to do this, not to mention counter-intuitive for the appeal of older, fast glass).

    Essentially I'm wondering if this merely an albeit fairly extreme example of the common problem with "cheap" ($50) adapters not being able to focus to infinity? It just seems so out in left field, im totally stumped.
     
  2. Petrochemist

    Petrochemist Mu-43 Top Veteran

    652
    Mar 21, 2013
    N Essex, UK
    Mike
    None of my cheap adapters have this issue. Though I've heard of many that focus beyond infinity (which one of mine certainly does). All the symptoms you describe indicate the adapter is thicker than it should be the distance between the mounting surfaces should be the difference in lens rear flange distances (25.46mm IIRC).

    I would certainly consider it faulty.
     
  3. RobWatson

    RobWatson Mu-43 Hall of Famer

    Yup, low quality adapters. Focus beyond infinity means adapter too thin while focus only close means adapter too thick. Too thick can be from some parts being loose so double check every surface to make sure nothing has come loose.

    28mm focal length and 7-8 feet max focus distance means off by quite a lot so possible even the wrong type of adapter?
     
  4. Grinch

    Grinch Mu-43 Top Veteran

    813
    Jan 9, 2011
    Canada
    Unfortunately you have fallen victim to Henry's over priced crap. Order a $15 dollar adapter off ebay and you'll probably end up with a better product for less. Send the Henry adapter back! I have/ had multiple adapters all from rainbow imaging and never had any issues. $50 for a simple adapter is way over priced!!!
     
  5. Curtox

    Curtox Mu-43 Rookie

    18
    Jun 11, 2013
    Nova Scotia, Canada
    Trust me, I never gave them a dime, Haha. I just tested it at the counter, both times.
     
  6. Curtox

    Curtox Mu-43 Rookie

    18
    Jun 11, 2013
    Nova Scotia, Canada
    Just to be sure I haven't missed something obvious, here's the link to the adapter: CAMERON PENTAX K LENS TO M-4/3 MT ADPT 8843070

    And of course the two lenses I've tried on it are the ones linked above.

    That is the correct adapter for use with my G3, right? It fits fine, and other the insane focus issue, seems bang on.
     
  7. dwig

    dwig Mu-43 Top Veteran

    622
    Jun 26, 2010
    Key West FL
    This indicates that the problem is that the adapters are too long. The extra "extension" causes the lenses to focus closer than designed. The effect of such extension is proportional to the focal length and should have roughly twice the effect on the 28 compared to the 55.

    Most of the similar "focus error" posts concerning legacy adapters are that the adapters are too thin and then lenses focus beyond infinity. This is because most manufacturers of cheap adapters target a somewhat thin adapter to allow for loose quality control. Even their longest sample won't be overly long.

    I have several "inexpensive" adapters from Fotodiox and all are slightly on the thin side.
     
  8. jakeblu

    jakeblu New to Mu-43

    3
    Mar 27, 2013
    I have a similar problem. Just bought a Carl Zeiss Tessar 50mm f2.8 from ebay m42 mount and I am having the same issues. The lens will focus on subjects up to 2-3mts away but not beyond that. Its a cheap ebay adapter but works fine on my others M42s. Is it the lens? I have searched for problems with the Tessars but haven't found any. Any help appreciated.
     
  9. Petrochemist

    Petrochemist Mu-43 Top Veteran

    652
    Mar 21, 2013
    N Essex, UK
    Mike
    If it's just with this lens, that suggests the lens is the issue.
    Is there any chance it's a rangefinder lens?
    I've not heard of any m42 rangefinders but I know m39 lenses were sold for rangefinders, and I've got a m39-m42 step up ring...
     
  10. dwig

    dwig Mu-43 Top Veteran

    622
    Jun 26, 2010
    Key West FL
    +1

    If the adapter works properly will all other lenses then this issue is with the lens that fails. Given it has an eBay source, it's likely had a DIY "repair" (cleaning, relube!, ...) and was reassembled improperly.
     
  11. jakeblu

    jakeblu New to Mu-43

    3
    Mar 27, 2013
    Looks like its back to the seller then.

    Thanks for your replies.

    steve