This adapter is meant for the Visoflex Leica M system which was Leica's way of creating a SLR camera out of their rangefinder cameras (http://camerapedia.wikia.com/wiki/Reflex_housing). The Visoflex lenses have a much longer Focal Flange Distance (FFD, https://en.wikipedia.org/wiki/Flange_focal_distance) than standard Leica M lenses to account for the additional mirror box that was added, this is why our adapter is so much thicker compared to other 35mm adapters for the Nikon system.
This adapter, when used with one of the Visoflex M lenses, will focus to infinity on any Nikon camera (both full fame frame and APS-C formats). However standard Leica M lenses not designed for the Visoflex system have a much shorter FFD and when used with this adapter will NOT focus to infinity, they will macro focus only (to a maximum of a couple feet).
Visoflex Use with Leica M Cameras
Visoflex is a mirror housing which converts an M camera from a rangefinder into a reflex camera. Compared with modern (D)SLR it is basic and primitive, but it is functional. It seems to have taken a new lease of life on the M8. It consists of a housing containing the mirror and a slide-on pentaprism. The pentaprism can be replaced by the straight finder. This finder switches right and left.
The advantages of Visoflex III over II are a higher clearance for higher M cameras, specifically the M5, M6 TTL, M7 and M8, a more functional mount which does not need the removal of the prism and handgrip, and a quick return/flip mirror setting.
There are two types we need to consider, Type II (production era 1959-1963) and Type III (1963-1984). Type I (1951-1962) is for screw-mount Leicas.
The two main uses are macro-photography and enabling longer lenses.
The more leisurely use of the Visoflex compared to modern SLR cameras is no handicap in macro. There a several ways to use it.
The most simple way is to use a normal M lens and mount it on the Visoflex, the bayonet is the same. As the Visoflex extends the lens-sensor distance, this is an instant Macro rig. Virtually any M lens may be used, but some lenses must be used at the 1 m setting instead of infinity, like the 35mm f/2 ASPH Summicron-M, to enable the rear lens element to clear the mirror. Recommended lenses are the 50mm f/2.8 Elmar-M collapsible (uncollapsed!!), the Elmarit f= 9 cm 1:2.8 and the 135mm f/4 Tele-Elmar.
Leica used to offer a beautifully-made bellows for the VisoflexUXOOR. This item is moderately rare on the used market. It uses various rings to connect with the lens heads of the Elmarit f= 9 cm 1:2.8, Summicron (I) f= 5 cm 1:2, Summicron (I) f= 9 cm 1:2,135mm f/4 Tele-Elmar, Elmar 135/2.8, 100mm f/4 Macro-Elmar-R, or the Photar micro-lens series.
The Novoflex bellows can be used on the Visoflex with adapter VISA which is still in the Novoflex catalogue and provides entrance to the whole range of use offered by that system.
The shortest lens that can be used on the Visoflex at infinity are1:3.5 / 65 Elmar and 1:3.5 / 65 Elmar-V using theUniversalschnecke (Universal Focussing Mount) 16464 OTZFO, which also serves for the lens heads of the Elmarit f= 9 cm 1:2.8and 135mm f/4 Tele-Elmar. The Schnecke for the 90mm f/2 Summicron-R and 135mm f/2.8 Elmarit-M I is 16462 ZOOEP.
There is a range of tele and long lenses. The most common ones are the F = 20 cm 1:4 Telyt, 1:4.8 / 280 Telyt I and 1:4.8 / 280 Telyt II, of which the latter is the most useful lens. They must be used with connecting ring 16466 OUBIO, except for 1:4.8 / 280 Telyt III, which mounts directly.
Then there are the long lenses. There are a 400, 560 and800mm f/6.3 Telyt-S of which the 400 and 560 exist in various configurations. All are achromats, i.e just two (or three for the800mm f/6.3 Telyt-S) kitted lenses in one element, real long lenses, not tele designs. The older F = 40 cm 1:5 Telyt I and1:5.6 / 560 Telyt are more or less obsolete due to strong field curvature, the newer F = 40 cm 1:5 Telyt II and 1:6.8 / 400 Telytexhibit this to a lesser, but still noticeable extent. Still, these are very good lenses for the purpose intended. They were offered in either a sliding mount, where focussing is obtained by sliding the lens barrel in and out and a Novoflex pistol mount, which could be squeezed for focus.
Novoflex themselves offered the Noflexar lenses in various lengths, 200, 240, 280 300, 400 and 600. Those are mainly three-element achromats of higher specification than the Leica offerings. The lens elements were made by Leica, and mounted in a barrel/grip made by Novoflex by an Agfa subsidiary.
There were three different pistol grips: Pigriff A, B and C.
They were mounted to the Visoflex through different rings. We need only concern us with Pigriff B and C. Pigriff B mounts through ring VISBA. Pigriff C is too long for the Visoflex and will not focus to infinity. However, Novoflex still offer a conversion service (2007) at a very reasonable price, after which the lens can be used fully with, again, ring VISA.
Although the use of the Visoflex for long lenses is more primitive and elaborate than a (D)SLR, it is, with practice, perfectly doable and gives excellent results.
Brightscreen offers a matte screen with Leica M8 markings engraved. - Jaap Vleeskruijer, 2007