/////Sigma 150-600mm Contemp – Canon 500D
Sigma 150-600mm Contemp – Canon 500D2017-09-18T14:58:00+02:00

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Sigma 150-600mm Contemp – Canon 500D

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  • Iwan
    Participant
    Post count: 8

    Hi all.

    I’m a little confused as to the mount on my Canon 500D (EF-S), if it will be compatible with the Sigma 150-600mm Contemporary Lens (EF). If the two are compatible, what does the “S” mean in EF-S?

    Thanks in advance.
    Iwan.

  • bomtek
    Moderator
    Post count: 1048

    The “s” stands for short back focus meaning that the flange distance is less than on an EF lens which is why EF lenses will fit on all Canon EOS bodies but EF-S lenses will only fit on APS-C bodies.

    Sigma make the mount of the 150-600 in an EF mount, meaning it will fit on all EOS bodies.

    Sigma lenses designated as DG (equivalent to EF) fit on all bodies whilst DC (equivalent to EF-S) will only fit on APS-C bodies.

    Hope this helps

  • Norm de Plume
    Participant
    Post count: 593

    @bomtek 297805 wrote:

    The “s” stands for short back focus meaning that the flange distance is less than on an EF lens which is why EF lenses will fit on all Canon EOS bodies but EF-S lenses will only fit on APS-C bodies.

    Or it stands for Small Image Circle. It depends on which of Canon’s Technical Reports you read.

  • bomtek
    Moderator
    Post count: 1048

    @Norm de Plume 297806 wrote:

    Or it stands for Small Image Circle. It depends on which of Canon’s Technical Reports you read.

    not really – the 300D introduced the first ef-s lens and the first technical report which mentions the ef-s mount makes reference to a smaller image circle but states that the “s” stands for short back focus. Essentially, they mean the same thing.

    Here is the excerpt in question;

    (5) Compatible with EF-S18-55mm f/3.5-5.6 USM
    The EF-S18-55mm f/3.5-5.6 USM (focal length range equivalent to 29-88mm in 35mm film) is a compact, lightweight standard zoom lens that was developed simultaneously and exclusively for the EOS Kiss Digital. While retaining the basic structure of the EF lens mount, the EF-S18-55mm f/3.5-5.6 USM incorporates a renewed design so as to optimally match the CMOS sensor size adopted in the EOS Kiss Digital.

    The EF-S18-55mm f/3.5-5.6 USM has a shorter back-focus (distance from the rear of the lens to the focal plane) and smaller image circle than other EF lenses to match the EOS Kiss Digital’s frame size of 22.7 x 15.1 mm, which made it possible to realize a wider angle of view, as well as a compact, lightweight lens.

    Because of the short back focus, the rear of the EF-S18-55mm f/3.5-5.6 USM intrudes into the camera body. The EOS Kiss Digital solves this problem by recessing the inner ring of body mount (see Fig. 7) by 3 mm and adopting a compact main reflex mirror that has a rear swing-up mechanism.
    The EF-S18-55mm f/3.5-5.6 USM cannot be physically attached to EOS SLR cameras other than the EOS Kiss Digital since the rear end sticks out further than other EF lenses.

    More information on the EF-S18-55mm f/3.5-5.6 USM will be provided in the next issue.
    * An “S” in the name of the EF-S lens comes from the first initial of the “short back focus.”

  • Iwan
    Participant
    Post count: 8

    @bomtek 297805 wrote:

    The “s” stands for short back focus meaning that the flange distance is less than on an EF lens which is why EF lenses will fit on all Canon EOS bodies but EF-S lenses will only fit on APS-C bodies.

    Sigma make the mount of the 150-600 in an EF mount, meaning it will fit on all EOS bodies.

    Sigma lenses designated as DG (equivalent to EF) fit on all bodies whilst DC (equivalent to EF-S) will only fit on APS-C bodies.

    Hope this helps

    Thanks very much Terry. It makes perfect sense. I’m gonna go ahead and buy that 150-600 then 😀

  • Norm de Plume
    Participant
    Post count: 593

    @bomtek 297807 wrote:

    not really – the 300D introduced the first ef-s lens and the first technical report which mentions the ef-s mount makes reference to a smaller image circle but states that the “s” stands for short back focus. Essentially, they mean the same thing.

    Here is the excerpt in question;

    And here’s the technical report from the first EF-S lens… so like I said, it all depends on which of Canon’s Technical Reports you reading. 🙂

    Feature 1: Compact, high performance optical system
    The new optical system developed for the EF-S18-55mm f/3.5-5.6 USM is optimized for CMOS sensor of the Advanced Photo System C size equipped to the EOS Kiss Digital. The EOS Kiss Digital adopts a compact main reflex mirror that moves back slightly as it swings up (refer to Technical Report September 2003 issue). Therefore back-focus (distance from the rear of the lens to the focal plane) of the lens can be made shorter than for the other EF lenses.

    In addition, the optical system is more compact because the image circle need only cover the image sensor diagonal. In the EF-S18-55mm f/3.5-5.6 USM, these factors all contribute to the optimization of the optical design, resulting in a compact optical system that provides an extended zoom rage as well as improved image quality (see Fig. 1).
    * The “S” in “EF-S” comes from “Small image circle.”

  • bomtek
    Moderator
    Post count: 1048

    I’m well aware of what the 2004 document says but I’m still inclined to go with the original document posted in 2003.

    What does the patent say?

    @Norm de Plume 297809 wrote:

    And here’s the technical report from the first EF-S lens… so like I said, it all depends on which of Canon’s Technical Reports you reading. 🙂

    Feature 1: Compact, high performance optical system
    The new optical system developed for the EF-S18-55mm f/3.5-5.6 USM is optimized for CMOS sensor of the Advanced Photo System C size equipped to the EOS Kiss Digital. The EOS Kiss Digital adopts a compact main reflex mirror that moves back slightly as it swings up (refer to Technical Report September 2003 issue). Therefore back-focus (distance from the rear of the lens to the focal plane) of the lens can be made shorter than for the other EF lenses.

    In addition, the optical system is more compact because the image circle need only cover the image sensor diagonal. In the EF-S18-55mm f/3.5-5.6 USM, these factors all contribute to the optimization of the optical design, resulting in a compact optical system that provides an extended zoom rage as well as improved image quality (see Fig. 1).
    * The “S” in “EF-S” comes from “Small image circle.”

  • Norm de Plume
    Participant
    Post count: 593

    @bomtek 297810 wrote:

    I’m well aware of what the 2004 document says but I’m still inclined to go with the original document posted in 2003.

    What does the patent say?

    I’m more inclined to go with the more recent document. Perhaps Canon decided to redefine it when they realised that short back focusing wasn’t going to be a feature of all their EF-S lenses and it might confuse people… whatever the reason is, I think they’re allowed to. 🙂

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