Cosina 50mm much sharper than my Jupiter-8 50mm

Discussion in 'Adapted Lenses' started by Ulfric M Douglas, Apr 26, 2010.

  1. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    Oh dear, I was hoping my LTM-mount Jupiter-8 (being small and black and barrel-shaped and therefore WAY COOLER on my G1 than my old Cosina Prime Pentax-K fit) would make me similar photos .. but so far it can't.
    These are both mounted on my Lumix G1.
    Cosina; (Composite of three shots at f2)
    [​IMG]
    Jupiter;
    [​IMG]
    There is no apparent fungus or haze or dust although surely a good clean is in order now.
     
  2. Bcostin

    Bcostin Mu-43 Rookie

    10
    Apr 10, 2010
    I daresay that's not typical for that lens. I don't have a Jupiter-8 in LTM to test, but my less-than-pristine Industar lenses give very nice results on my E-P1, even wide open.

    It would take a very visible amount of hazing or fungus to give results that soft. I'd guess the lens is misaligned or damaged in some way, or that the adapter is out of spec. Do you have other LTM lenses you could try with that mount adapter?
     
  3. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    I have an Industar-61 coming, the 50mm I think ... on a Fed4 body.
    The adapter allows the correct close and infinity focus : that's about all it can do. I used the lens hand-held without an adapter last week with similar results.
    I guess I'll know more after the next lens arrives.

    Meanwhile, here's a very cropped composite taken with the Pentax110-18mmWideangle using homemade adapter ;
    [​IMG]

    And here's my new Fed61 52mm at F2.8
    [​IMG]
    and at F4
    [​IMG]
     
  4. cosinaphile

    cosinaphile Mu-43 All-Pro Charter Member

    Dec 26, 2009
    new york city
    its my understanding that only 2 japanese companies actually manufacture their own glass from scratch

    nikon and cosina ,i believe cosina also manufactuered the bodies for the much sought epson digital rf made some years back, as well as modern voigtlander lenses and the current crop of zeiss lenses . and also other products

    im not surprised that the cosina is a stellar performer , the optical heritage is there
     
  5. Brian S

    Brian S Mu-43 Top Veteran Charter Member

    714
    Apr 11, 2009
    There is something wrong with the J-8, the optics are probably misassembled.

    My 1955 KMZ J-8, wide-open at F2 on the Canon P.
    [​IMG]

    I had a problem with a Zeiss Sonnar that produced images like yours: the rear group was in backwards.
     
  6. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    Well, now that I've got my Fed which looks even better on the G1 I can afford to disassemble the Jupiter ... maybe.
    Wish me luck! :eek:
     
  7. Brian S

    Brian S Mu-43 Top Veteran Charter Member

    714
    Apr 11, 2009
    Good Luck! Post some pictures of the process, and ask questions. I've done a couple of these.

    A few months back I repaired a Summicron for a friend that had THREE of the lens groups in backwards. I learned a long time ago to put a DOT with a Sharpie on the surface that faces outwards.
     
  8. cosinaphile

    cosinaphile Mu-43 All-Pro Charter Member

    Dec 26, 2009
    new york city
    if its just the rear element it should just be unscrew flip element [clean well with microfiber]
    screw in retaining ring
     
  9. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    The rear element is a 'tubular' unit containing at least 2 lenses and cannot be disassembled further. It only goes in one way. So ... there is nothing that can be reversed in this particular lens. I can clean it and try it at different levels of 'screwed-back-togetherness'.
    Here's the result on this damp grey morning ;
    [​IMG]
    Hmm ... better!
    Oh hell ... WAY BETTER!
    [​IMG]
    There must have been something on the inner surface of the rear llens element. Yeay.

    Here's my home-made lens-ring unscrewer device;
    [​IMG]

    I found an interesting titbit from Aoleg on MFlens forum;
     
  10. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    I was randomly browsing e-bay for more lenses when I bid on a Zenit SLR in case with Helios44M,58mm,f2 elns,flash and 2x adapter.
    When it arrived I tried to find a local screw-to-P-K adapter since I have P-K to 4/3rds & m4/3rds already.
    Found ... something ... wasn't what it said ...
    Never mind, I've SUPERGLUED the helios lens onto my P-K-to-m4/3rds adapter. Yes.
    At f2.8 I reckon sharp and nice;
    [​IMG]
     
  11. Bokeh Diem

    Bokeh Diem Mu-43 Top Veteran

    655
    Mar 14, 2010
    Toronto
    ... and at that point he became known as Superglue Ulfric.

    Nice home made work around!

    Bokeh D
     
  12. Ulfric M Douglas

    Ulfric M Douglas Mu-43 Hall of Famer

    Mar 6, 2010
    Northumberland
    Hmm, but when I want to fit my Tokyo-Koki 300mm on the G1 I can't! Never mind, if I get any more 42mm thread lenses I'll buy a proper adapter.
    The superglue-special does look a bit massive though, so I took my little industar to Carlisle Steam fair instead.
    Lens flare!