Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,933   Posts: 1,585,541   Online: 859
      
Page 8 of 8 FirstFirst ... 2345678
Results 71 to 78 of 78
  1. #71
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,438
    Images
    148
    Quote Originally Posted by sanking View Post
    Just for the record, many of the early G-Claron lenses are of Dagor design, not plasmat. I own two lenses of this type, a 210mm and a 240mm. They are single coated and excellent performers, giving more contrast in fact than single coated plasmat type lenses because of fewer air to glass surfaces.

    Sandy King
    My point was more that the G-Claron's are Repro lenses and not optimised for Infinity or normal use,of course there were Repro Dagors to. In many cases that in itself may make little difference but there can be problems.

    One problem with any Graphics/Repro lens is they are optimised for flat field work usually at 1:1 and in the case of the G Claron best between 5:1 and 1:5.

    While Schneider state they can be used for normal photographic work they state they can be used up to an angle of view of 64 degrees, less than a Symmar or Sironar.

    The image circle might be much greater but there are issues of spherical distortion using process lenses at or near infinity. This may be an problem at the edges/corners, obviously some designs will be worse than others.

    It's possible that the early Dagor type Claron's are better than the later Plasmat designs in this respect but they still aren't optimised for normal use.

    Ian

  2. #72

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by Steve Hamley View Post
    Mike,

    No, the earliest G-Clarons are a Dagor design, a 6-glass, 2 group lens, or a lens comprised of 2 cemented triplets. Dagors never changed in the design of the groups while the G-Claron did.

    Single coated lenses have more contrast than uncoated, and at least to me, modern multicoated lenses have more contrast than single coated. The effects of coating boosting contrast was mentioned by Ansel Adams in one of his books, and he suggests that development may have to be altered because of it.

    Cheers, Steve
    Some years ago I owned and used mostly vintage lenses for my ULF work. That included several uncoated Dagors and Protars. When I replaced one of the uncoated Dagors with a modern multi-coated Nikkor M lens I had to decrease development time by about 25% to account for the much greater contrast of the multi-coated lens.

    That said, the single coated Dagor design G-Claron lenses are great value. Late model coated Dagors of the same vintage, Kern for example, generally sell for a lot more than the Dagor type G-Clarons, in part I think because not many people are aware of the fact that early G-Claron are in fact Dagors.

    As for the ultimate in contrast, try a multi-coated Dagor, say the 14" Kern Dagor or the Schneider 550 XXL. With only four air to glass surfaces and multi-coating you get a very contrasty negative with these lenses.

    Sandy King

  3. #73
    df cardwell's Avatar
    Join Date
    Jul 2005
    Location
    Dearborn,Michigan & Cape Breton Island
    Shooter
    Multi Format
    Posts
    3,342
    Images
    8
    There's an exchange between Paul Strand and Ansel Adams, published (IIRC) in AA's Letters.

    Strand had his prized Dagor coated after WW2, and it forced him to change his way of shooting: single coating a Dagor (or Protar) removes the flare from the deepest shadows which affectively provided the Zone I density; like a single exposure unit of Pre-Exposure. To compensate, Strand (and all of us since) had to double his exposure. A MC lens might approach a two Zone loss of density compared to an uncoated Dagor/Protar.

    The higher up the scale, the less the effect of flare. By Zone III, flare is non-existent. But an uncoated lens is perfectly capable of extremely contrasty results. Only when we compare contrast side-to-side, do we se the difference. If you increase the development, you get sufficient contrast with an uncoated lens fir B&W. Color is a different set of issues.

    Then again, coating 'flare monsters' like Plasmats and Cooke Convertibles made them far more useful.
    Last edited by df cardwell; 12-22-2009 at 11:24 AM. Click to view previous post history.
    "One of the painful things about our time is that those who feel certainty are stupid,
    and those with any imagination and understanding are filled with doubt and indecision"

    -Bertrand Russell

  4. #74

    Join Date
    Sep 2002
    Location
    Knoxville, TN
    Shooter
    Multi Format
    Posts
    453
    Hey Sandy,

    On what formats do you find the 450mm Nikkor M usable for contact printing?

    Cheers, Steve

  5. #75

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by Steve Hamley View Post
    Hey Sandy,

    On what formats do you find the 450mm Nikkor M usable for contact printing?

    Cheers, Steve
    The 450mm Nikkor M is a great lens for 14X17, 12X20 and 16X20, if you stop down to f/22 or so. Also works for 20X24 if you stop down to f/64 or f/90, but the corners will be soft.

    Sandy

  6. #76

    Join Date
    Sep 2002
    Location
    Knoxville, TN
    Shooter
    Multi Format
    Posts
    453
    Thanks Sandy.

    Cheers, Steve

  7. #77
    Mustafa Umut Sarac's Avatar
    Join Date
    Oct 2006
    Location
    İstanbul - Türkiye
    Shooter
    35mm RF
    Posts
    3,966
    Images
    108
    I become a crossfield 656 drum scanner operator after seeing ansel dagor prints.
    After 10 years of research and entering to internet age , I wrote to Zeiss Archives and asked what do they have in their hands about dagors. They sent two pages scan , prescriptions of Dagor 300 and 350 mm.
    After looking , thinking about hundreds of lenses , you can see how dagor design is genius , rafinery and intelligent. At 350 , there are two symmetric group of glasses and a middle air section.
    There is no air gap between each glass of these groups and it impress the observer.
    I discussed the cooke xv design with cooke head designer and he sent me prescriptions and glass details.
    It is now impossible to find every detail of these glasses for these lenses. It is lost.
    May be I will buy them , disassemble and send them to analysis. Than copy with sol gel

    Mustafa Umut Sarac

  8. #78
    luvcameras's Avatar
    Join Date
    Jan 2005
    Shooter
    Multi Format
    Posts
    381
    For you antique Dagor Fans, a catalog section of all the Goerz Dagor lenses as of 1904 here

    http://antiquecameras.net/1904goerzlensads.html

    Dan
    Antique and Classic Camera BLOG
    www.antiquecameras.net/blog.html

Page 8 of 8 FirstFirst ... 2345678


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin