Reducing depth of field on RZ67

Discussion in 'Medium Format Cameras and Accessories' started by Cyberdog, Feb 20, 2006.

  1. Cyberdog

    Cyberdog Member

    Messages:
    6
    Joined:
    Jan 11, 2005
    Location:
    London, UK
    Shooter:
    Medium Format
    I have an RZ67 Professional body with the 250mm f4.5 lens and I'm wondering if there is any way I can get a very narrow depth of field (similar to 1.4 or 2.8) with the lens I have.

    I can't affort to shell out for a 2.8 lens and I'm looking for a shortcut.

    I appreciate any suggestions anyone can offer. Thanks!
     
  2. Helen B

    Helen B Member

    Messages:
    1,557
    Joined:
    Jul 1, 2004
    Location:
    Hell's Kitch
    Shooter:
    Multi Format
    Do you have any faster lenses at other focal lengths? Could they be used instead? Is the 250 mm perspective important?

    Best,
    Helen
     
  3. Donald Miller

    Donald Miller Member

    Messages:
    6,242
    Joined:
    Dec 21, 2002
    Shooter:
    Large Format
    I gather from your post that you are more familiar with 35 mm then you are with medium format. The lens selection available to medium format is usually far more limited and the lenses typically have a smaller maximum aperture then a 35 mm lens. There is no 2.8 or 1.4 lens of the focal length that you have offered by Mamiya according to my information.

    Since aperture is a measurement of iris opening related to focal length of a lens this really is not as much of a problem as one would at first assume because longer focal lengths have a shorter equivalency when compared to the 35 mm format.

    If you were doing close up photography, you could opt for close up lenses as supplements to your prime lens. This would give you a greatly diminished depth of field.

    http://www.camerafilters.com/pages/closeup.aspx

    Good luck.
     
  4. Marco Gilardetti

    Marco Gilardetti Member

    Messages:
    420
    Joined:
    Jun 7, 2005
    Location:
    Torino, Ital
    Shooter:
    Large Format
    If you could expand what you have in mind, perhaps that would help. I personally think that DOF with a 250mm f:4,5 (the sole ever released for the RB/RZ system AFAIK) is so shallow to be a compelling problem all of the times. I can hardly understand what use could have a DOF reduced even further.
     
  5. Cyberdog

    Cyberdog Member

    Messages:
    6
    Joined:
    Jan 11, 2005
    Location:
    London, UK
    Shooter:
    Medium Format
    I am indeed. I have only had the camera a short while, and I'm just now getting my feet wet. To be honest, I haven't experimented too much with it yet. This question was more out of curiosity than anything else.

    I just bought a polaroid back, so I can experiment a bit more without completely breaking the bank.

    Thanks for your comments.
     
  6. jedrek

    jedrek Member

    Messages:
    22
    Joined:
    Mar 4, 2006
    Location:
    Krakow, Pola
    Shooter:
    Multi Format
    Check out the online DOF Calculator to see what your DOF will be with different focal lengths/formats/apertures. Your 250mm f/4.5 will give you 3cm of DOF at 2m - that's not a lot at all.
     
  7. forksphoto

    forksphoto Member

    Messages:
    26
    Joined:
    Jan 5, 2006
    Location:
    San Antonio,
    Shooter:
    Multi Format
    Additionally MAC has the DOF tables published. I assume the Sekor C and Sekor Z 250 F4.5 would have exactly the same DOF, and the chart is here:
    http://www.macuserforums.com/webx?14@174.xV17a4ILtvX.2@.ee73b9d

    I have another idea, but I'm not positive if it will reduce DOF, how about using an extension tube, It will reduce your working distance and should effectively reduce DOF along with it, but I'm not positive about that, someone will set me straight real quick if I'm out of order.

    Forks
     
  8. benjiboy

    benjiboy Subscriber

    Messages:
    8,688
    Joined:
    Apr 18, 2005
    Location:
    U.K.
    Shooter:
    Multi Format
    New to the medium

    I think you most be new to M/F Cybordog, with a 250mm lens the D.O.F. at large apertures is very limited indeed theres no such animal as a 250mm 1.4 or 2.8 for 6x7, and if there was it would be too heavy to pick up. Try doing some shots at 4.5 and the larger lens openings as a test, I can't believe that you get too much D.O.F with this optic.