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Kenko DG Extension Tube Set for Nikon F

Discussion in 'Lens Matters' started by A.B-C, Jun 5, 2021.

  1. A.B-C

    A.B-C Member

    Hi all,

    I'm aware that there are other discussions of this topic on the internet. However, I can't seem to find consistent information on the subject.

    Does anyone have experience using the Kendo DG Extension Tube Set with Nikon F Mount? If so, have you found that your lenses retain their functionality? In their description of the product, Wex claim that AF-S lenses lose the ability to autofocus. However, has anyone had success with other brand lenses or with Nikon's screw-driven lenses?

    Thanks in advance!
     
  2. PeteRob

    PeteRob Well-Known Member

    To retain auto focussing the lens would have to have a motor and the tubes would have to pass through the requisite information and power to the lens. Their technical data specification should say. Tubes are usually fairly simple things - they just provide a gap - so I’d think focussing would be manual, which suits the application which is for macro or greater magnification photography. The specification on the Kenko website only says that exposure (aperture) information is passed through. https://kenkoglobal.com/product/extension_tube_set_dg_for_nikon_f/#specifications
     
    A.B-C likes this.
  3. A.B-C

    A.B-C Member

    Thanks for the answer PeteRob! Don't know why I didn't think about enlarging the pictures on Kenko's own site, but it looks like the tubes have the same screw drive mechanism that is present on some camera bodies. Seems like lenses where focus is screw-driven would retain autofocus.
     
  4. GeoffR

    GeoffR Well-Known Member

    With AI or AI-S lenses that coupling is mechanical (not present on the linked tubes), with any flavour of AF lens it is electrical (AF and AF-D can couple mechanically) but it gets complicated. A mechanical AF drive through the tubes is possible, and apparently present, but I would expect the degree of lost motion to make it rather unreliable. Again lenses with built in motors could be driven electrically. The set Pete has linked to does appear to have a set of electrical contacts but only 7 of them and AF-S G series lenses have 10 but cameras have only 8 (D4, I can't check anything more recent) so some functions will work but only Nikon could tell you which ones.
     
    A.B-C likes this.
  5. A.B-C

    A.B-C Member

    Thanks GeoffR, I take it the electrical contacts are those pin-like protrusions?

    I may just find a second-hand set and experiment with those. It wouldn't be a lot of money to lose if they turn out to be rubbish, and I'll at least have manual autofocus as PeteRob reccomends. I'm a bit worried about the seals letting in detritus when in use, but I suppose that's nothing a bit of electrical tape can't solve. I'll update this thread with any observations.
     
  6. GeoffR

    GeoffR Well-Known Member

    The electrical contacts are inside the throat of the lens mount. The protrusions are, the lens lock pin, the focus drive and the black one appears to be an aperture coupling dog, which I originally thought was absent.
     
    A.B-C likes this.
  7. A.B-C

    A.B-C Member

    Thanks, really want to learn about lens coupling mechanisms now!
     
  8. GeoffR

    GeoffR Well-Known Member

    Canon, all electrical
    Nikon, heading to all electrical (Z series) but a lever in the throat of the camera operates the aperture stop down. On older lenses/cameras a ring around the lens mount couples with a flange on the aperture ring on the lens to convey selected aperture. Even older lenses have rabbit ears that couple with a pin on the metering system (you can't use them on current cameras without camera modification.
    Pentax, can't remember.
    Olympus OM was mechanical coupling.
    Most other current cameras couple electrically unless you are talking about larger formats.
     
    A.B-C likes this.
  9. A.B-C

    A.B-C Member

    That's really interesting, and a bit of a shame, as they (Nikon) have some great and affordable lenses that still use screw-drive autofocus.
     
  10. A.B-C

    A.B-C Member

    Just won a good condition set in an eBay auction (my first) for £31, I'll put them through their paces and post the results.
     

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