59 years after, a new Nikon mount…

I don’t want this blog to turn into a Nikon fansite. But Nikon related pages are now the most read: the Nikon D700 and FE2 entries have been the two most visited pages lately, leapfrogging the pages related to the Angenieux 28-70 f/2.6 zoom, which had been the readers’ favorite for years. And I can’t hide that Nikon film cameras are those I prefer, and that I’ve put my money where my mouth was.

Interesting things are happening at Nikon’s. On August 23rd, they will unveil a new full frame mirrorless digital system, launch a new lens mount and at least one lens.

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Teaser from Nikon: the silhouette of Nikon’s new mirrorless body, and its huge lens mount. It looks much simpler than the Nikon F mount below,

The new lens mount will be typical of modern mirrorless cameras (short flange distance, and, I assume, no mechanical interface at all – autofocus and aperture control being all electric ), but its diameter will be unusually large – much larger in any case that the Sony E lens mount.

Nikon’s micro site presenting the new lens mount: https://www.nikonusa.com/en/nikon-products/mirrorless-is-coming.page

Over its 59 years of commercial life (so far), the Nikon F mount has gone through many revisions to support successively aperture indexing, automatic aperture indexing, matrix metering, auto-focus, silent wave auto-focus motors, and more recently, electronic diaphragm control.

Because Nikon has made a core business principle to guarantee at least a modicum of compatibility between its older lenses and its newer generation of bodies (particularly for high-end cameras sold to professionals), the new full frame mirrorless body will accept Nikon F lenses, via an adapter. But Nikon has not shared any detail about this adapter yet.

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Nikon F mount – clockwise from top, on the mount’s flange : the meter coupling lever used for aperture indexing, the lens type signal pin, the lens release pin, the auto-focus shaft. On the inside of the exposure chamber: the electrical contacts used by AF lenses (top), the focal length indexing pin (right) and the aperture stop-down lever (left).
  • The adapter could be made simple, with no electrical contact and no mechanical linkage to the lens. Generally speaking, mirrorless cameras are not dependent on the automatic aperture pre-selection capabilities of the lens, so it’s likely that any Nikon F lens old enough to have an aperture ring will not only physically mount on the adapter, but will somehow work when the camera is set to semi-automatic exposure and manual focus mode. But recent lenses deprived of an aperture ring (or with an electronic control of the aperture) would not work with such a simple adapter. Which would go against Nikon’s tradition of preserving compatibility in priority for recent and/or expensive pieces of equipment.
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2 very simple adapters: Canon FD to Fujifilm X (left), Nikon F to Fujifilm X (right). In both cases the mirrorless body does not control the aperture on the lens (no pre-selection, no shutter priority or program automatism).
  • The adapter could be made very complex. Sony supports Minolta/Konica-Minolta/Sony A mount lenses on its E Mount mirrorless bodies thanks to two models of adapters. The most complex of the two, the LA-E4, has its own autofocus motor in order to provide support and adequate AF performance for screw-drive autofocus lenses (which still constitute the majority of the Series A lenses offered by Sony today). Sony’s adapter also has a Phase Detection AF module, probably because its A series lenses were not designed for the contrast detection auto-focus system of its NEX mirrorless bodies.

    Nikon’s original AF and AF-D lenses (the screw drive lenses without an auto focus motor) could be supported using a similar setup if Nikon really wanted to, but I doubt they’ll have any appetite for such a solution (one of the reasons being that professionals have been buying AF-S lenses with a built-in auto focus motor for almost 20 years now – and probably don’t use many screw-drive auto-focus lenses anymore).

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    Sony LA-E4 A NEX Camera Mount Adapter (Source: Adorama). With its built-in auto-focus motor, it accepts any Minolta/Konica/Sony A lens (with the AF drive shaft), and its Phase detection AF module behind a semi-transparent mirror offered better performance than the contrast detection AF of the early Sony Nex bodies.
  • Nikon’s now defunct One series (J1 to J5 viewfinder-less cameras and V1 to V3 SLR like models) could accept F mount lenses thanks to an adapter. With the FT1 adapter, auto-focus lenses with a built-in auto-focus motor (AF-S lenses, with or without an aperture ring) are fully supported (all auto-exposure modes, vibration reduction and auto-focus, of course).
    Older auto-focus lenses (the AF and AF-D lenses) can be used in all the auto-exposure modes but don’t auto-focus. Lastly, AI and AI-S manual focus lenses will only be usable in Manual or Aperture Priority Auto Exposure modes.

Nikon FT1: compatible modes: https://imaging.nikon.com/lineup/acil/lenses/mount_adapter_ft1/restrictions.htm

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Nikon FT1 adapter (Nikon F to Nikon One lens mount adapter) – Source: Adorama

My bet is that the new adapter will offer the same functions as the FT1. It will fully support any lens introduced in the market since the last years of the XXth century (AF-S, AF-S G, VR, AF-P), and with reduced capabilities, most of the older lenses.

Will there be a penalty in terms of auto-focus performance for users of AF-S lenses ?

That’s the real question.

First answers on Aug. 23rd…


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Massada (Israel) – Kodak CN400, Nikon F501 – Nikon E series 35mm f/2.5 lens.