Extenders

Discussion in 'Beginner Questions' started by Ken Thomson, Jun 17, 2022.

  1. Ken Thomson

    Ken Thomson New Member

    Joined:
    Jun 17, 2022
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    2
    Equipment:
    7D mark2 x 3 and 5D mark4 numerous L lenses
    Hi,
    Can any one tell why when I connect an Ef 2X III to my EF 100-400mm f/4.5-5.6 L IS USM and have the camera in Manual mode that the auto focus and IS do not operate.
     
    Ken Thomson, Jun 17, 2022
    #1

  2. johnsey

    johnsey Site Moderator Staff Member Site Supporter

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    Fargo, ND
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    5dMk4, 5dsR, 5dMk2, 20D, 70-200 2.8L IS, 100mm 2.8 Macro USM, 50mm 1.4, 85mm 1.8, 17-40mm 4.0L, TS-E 24mm 3.5L II, Rokinon 14mm 2.8; Pixma Pro-100
    johnsey, Jun 17, 2022
    #2
  3. Craig Sherriff

    Craig Sherriff Well-Known Member Site Supporter

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    60D,350D 1dmark3, T70, AV1, lenses ranging from 28mm to 600 mm, canonet Junior, Canonet QL 25, Mamiya C3 and 3 lens sets,Mamiya 645 pro TL and 3 lenses.Mamiya universal press camera and 4 lenses, Mamiya RB67 Pro S and 5 lenses, Pentax MG and various lenses, Toyoview 4 * 5 inch large format camera,Calimat C1 8*10 inch ultra large format camera.
    Welcome to the forum, Ken. Not much more i can add. With any gear we use there are limitations, with this 2X extender, this is one of them.
     
    Craig Sherriff, Jun 17, 2022
    #3
  4. GDN

    GDN Well-Known Member

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    A little Canon stuff
    Depending on which dslr camera body, some cameras require a lens no slower than f5.6 to autofocus, and then there are others that will focus at f8. As far as know, there are none that autofocus with lenses slower than that. So if you attach any lens with an aperture of f5.6, and then add a 2x extender, you loose two stops of light. Your f5.6 becomes f11 with this extender. If you were to use this lens with the EF1.4 extender, you loose one stop of light only, so your f5.6 lens becomes a f8 lens. If you look at the first link that Johnsey posted, it gives the list of bodies that will focus at f8.

    Just as a point of interest, mirrorless bodies will focus at f11. Just saying.

    Gary
     
    GDN, Jun 18, 2022
    #4

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