I have a Soligor 450 mm lens with a 40 mm dia camera body end thread connection. I would like to try adapting it to a D90 AF system. Are there adapter rings available out there for this purpose?


Soligor 450mm lens is a manual focus lens. There should be adapters, but none of them will make AF work.


Assuming it is an M42 lens as some research on the particular model suggests, M42 to F mount adapters are readily available.

But since the M42 register is shorter than the Nikon one, you'll have to choose between two types of adapters: those which do not preserve infinity focus (by being indeed short extension tubes) and those who compensate with a generally poor quality element. In this peculiar case, with the difference being barely over 1 mm, some adapters without extra glass allegedly capable of infinity focus exist, but keep in mind the manufacturing tolerances on such cheap items are often too relaxed for being a critical component of the optical path.

As already stated by Evaldas, none of them will enable autofocus, especially since this lens has a minimum aperture of ƒ:8 and Nikon only guarantees operation of the AF (and focusing assist) system at apertures larger than ƒ:5.6.

  • Well, newer Nikon bodies (such as the D800) can do AF at f/8, which is why some of us will buy the new 80-400mm with a 1.4 TC. However, even that won't help an M42 lens... None of them have AF that I'm aware of.
    – Joanne C
    Apr 3 '13 at 2:08
  • Since you're manually focusing anyway, does it really matter if the manufacturing tolerances are off? (Assuming variation in thickness, as long as you get one that's thin enough....)
    – mattdm
    Apr 3 '13 at 15:43
  • 1
    @mattdm: Likely, as distance affects the focused distance and when those classic lenses claim a working distance of, let's say 1m~∞, that's it. Ironically, this could be a minimal issue with modern Nikkor ED lenses which focus can be adjusted further than infinity (allegedly to compensate for dilatation of the barrel, mount and elements at high temperatures)...
    – Ryccardo
    Apr 3 '13 at 16:07

As already explained, M42 screw-mount lenses won't focus to infinity on F-mount bodies (Nikon and some Fujifilm SLRs) due to negative difference in lens-mount register distance.

But, since you're trying to use long telephoto lens, you would get working infinity focus, regardless of inherent mount incompatibility - long-focal lenses usually focus past infinity mark enough for smaller register difference. Since register difference between M42 screw-mount and F-mount is 1mm (45.46mm vs. 46.5mm), 450mm lens would probably focus to infinify just fine.

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