Canon 5D vs. Sigma DC Lenses

DKing9DKing9 Users Awaiting Email Confirmation Posts: 6 Big grins
edited February 17, 2007 in Cameras
Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??

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  • AndyAndy Registered Users Posts: 50,016 Major grins
    edited February 15, 2007
    DKing9 wrote:
    Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??
    Why the flame icon? Those lenses are designed for digital bodies, 1.6x crop factors.
    Andy

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  • cmasoncmason Registered Users Posts: 2,506 Major grins
    edited February 15, 2007
    DKing9 wrote:
    Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??

    No settings, those are DC lenses. DC lenses are "Specially designed for digital SLR cameras with an APS-C size image sensor" as described by Sigma. This is one of the issues with buying lenses designed for crop sensor cameras, (and an issue with going with a 5D if you have these lenses).
    Photos
  • ziggy53ziggy53 Super Moderators Posts: 24,078 moderator
    edited February 15, 2007
    DKing9 wrote:
    Just received my new 5D body (started with a 20D) and when attempting to use my Sigma 50-150mm and the 17-55mm I get a black circle around the photo. I know that the 5D is full frame but are there settings that do not make my Sigma glass obsolete??

    That would be; no, yes and maybe.

    The "no" part is that your lenses are designed for a 1.6x "crop" camera, which has a reduced sized imaging chip. Those lenses, by themselves, will not fill a full-sized imager or full-frame 35mm film camera.

    The "yes" part is that you will get an image that you can crop from the center portion to yield a decent 4 x 5 aspect ratio with around 6 MegaPixels resolution.

    The "maybe" part is that you might be able to use a 1.4x teleconverter on the 50-150mm lens, in the 100-150mm range, that might get closer to a full-frame image circle. The edges of the image will suffer, probably pretty badly, but it might be a useful expedient, and you could use the teleconverter later.

    I don't think you will be happy with any of the above, so my first recommendation is that you purchase a Canon 50mm, f1.8 II, which is about the cheapest quality lens you can buy. Ultimately, you will probably want to get some new lenses, more appropriate for the new camera.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • DKing9DKing9 Users Awaiting Email Confirmation Posts: 6 Big grins
    edited February 15, 2007
    Thanks for the info. I do have a teleconverter so I will try my luck with that but ultimately I will be getting more lenses. Very helpful!!!
  • pathfinderpathfinder Super Moderators Posts: 14,703 moderator
    edited February 16, 2007
    Lenses are designed to create an image over a specific circular area in the sensor plane.

    For example, lenses for an 8x10 view camera have to create an image that covers a full 8x10 glass viewing plate, or an image circle about 10 inches in diameter.

    35mm lenses for full frame 35mm cameras create an image circle that is ~ 36mm in diameter, since a 35mm frame is 24 x 36mm in size.

    Lenses designed for an APS sensor need only cover about a 23mm circle, since APS sensors are 14.8 x 22.2mm in size, hence the vingetting you noticed.
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • DoctorItDoctorIt Administrators Posts: 11,951 moderator
    edited February 16, 2007
    Anybody mind if I change the title of this thread to specify "DC" lenses? with the flamey face, this really comes off as bashing of what is otherwise good glass.
    Erik
    moderator of: The Flea Market [ guidelines ]

  • ziggy53ziggy53 Super Moderators Posts: 24,078 moderator
    edited February 16, 2007
    DoctorIt wrote:
    Anybody mind if I change the title of this thread to specify "DC" lenses? with the flamey face, this really comes off as bashing of what is otherwise good glass.

    That seems reasonable to me.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • Manfr3dManfr3d Registered Users Posts: 2,008 Major grins
    edited February 17, 2007
    Andy wrote:
    Why the flame icon? Those lenses are designed for digital bodies, 1.6x crop factors.

    Not to forget 1.5x crop factor bodies (Nikon, Pentax). mwink.gif
    “To consult the rules of composition before making a picture is a little like consulting the law of gravitation before going for a walk.”
    ― Edward Weston
  • Art ScottArt Scott Registered Users Posts: 8,959 Major grins
    edited February 17, 2007
    Andy wrote:
    Those lenses are designed for digital bodies, 1.6x crop factors.
    Manfr3d wrote:
    Not to forget 1.5x crop factor bodies (Nikon, Pentax). mwink.gif

    Let's not forget Konica/Minota/Sony 1.5 crop factor either...:D
    "Genuine Fractals was, is and will always be the best solution for enlarging digital photos." ....Vincent Versace ... ... COPYRIGHT YOUR WORK ONLINE ... ... My Website

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