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I'm looking to purchase a set of extension tubes, and a seller I'm talking to is selling a set of Kenko extension tubes, pre-DG model. I could not find any information about what DG stands for when it comes to extension tubes, nor could I find any information on pre-DG models of the Kenko extension tubes. Can someone please explain what the "DG" means, and what the differences between DG and non-DG models of Kenko extension tubes are (if such a thing exists)?

Additional information: I am looking to purchase a set of Kenko extension tubes for a Nikon D3200, for use in macro shots.

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'Digital Gate-Array IC', whatever that means.

According to Kenko:

It means the converter’s unique circuitry maintains signal integrity between the camera body and lens.

From that one could surmise that Kenko DG or DGX products are made to allow communication between the camera and lens.

The DG series of products is designed to work better with digital DSLRs and the DX only lenses often used with them. The main difference would probably be the lack of an aperture control ring on DX lenses.

If you are using a lens that relies on an electrical signal from the camera to set the aperture value of the lens this would be a necessity to allow normal operation of the lens' aperture. It also means that without the electronic connection your camera will not electronically detect the lens. At least some of the pre-DG products apparently also had pass-through electrical connections.

If your camera is unable to shoot in Manual exposure mode without communication from a lens, you would not be able to use "dumb" extension tubes that do not allow your camera to communicate with your lens.

In the case of teleconverters, the 'X' also means the signal from the lens is translated to reflect the changes to focal length and aperture that occur when attached to the TC. For example, if I shoot at maximum focal length with maximum aperture using an EF 70-200mm f/2.8 lens and a Kenko Teleplus Pro 300 AF 2.0X DGX, it reports a focal length of 400mm and f/5.6 to the camera.

  • pre-DG Kenko adapters also had electrical communication through to the lens. I had a set, they "worked" with Nikon AF-S lenses I had. Although, they seemed flaky. Kenko's marketing pitch used to say "This DG Extension tube set has upgraded 'Gate-Array IC' circuitry to work better with digital SLR's and some of the digital SLR lenses, like the Nikon DX (e.g. 17-55mm, 10.5mm) digital-only lenses." (from this answer a few years ago) – scottbb Jul 25 '17 at 1:48
  • Gate-array logic ICs are old technology (late 70's). It was an early form of programmable logic, cheap to implement, cheap to produce. Kenko touting their DG is something akin to automakers touting power windows with a special moniker. – scottbb Jul 25 '17 at 1:56
  • Yeah, I'm a little familiar with the term in the context of logical circuits, just not sure what Kenko meant by using it to apply to a pass-through connection. It makes more sense with the DGX TCs, which do translate the reported Av and focal length. – Michael C Jul 25 '17 at 2:11
  • I figured they were using the circuits as nothing more than buffers, perhaps to counter flaky electrical connections. – scottbb Jul 25 '17 at 2:13
  • Do the DG extension tubes translate the Av to account for the light lost due to the extension tube for EXIF reporting purposes? – Michael C Jul 25 '17 at 2:14

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