I'm looking for a very cheap (~$50), fast (large aperture), full manual (non-CPU) lens for my Nikon D7000. After searching on eBay, I found that the same lenses (e.g. Vivitar 135mm f/2.8) are cheaper for older mounts (M42, Canon FD etc.) than the Nikon F-mount.

Is there a difference in using a full manual F-mount lens with or the same lens for another mount with an adapter?


3 Answers 3


Sadly for Nikon users, the F mount has one of the longest registers ever.

(Mechanically) adapting a lens designed for a certain system to one with a shorter register is easy: just manufacture an extension tube of the correct length. The ability of controlling the lens will be mostly lost but this is less of an issue with lenses with mechanical aperture rings.

Doing the opposite is impossible: there are thus two possible solutions to the problem.

  • Design an adapter adding the least possible distance and let it be: the lens will be limited to close-up work and will become unsuitable for general photography.

  • Add a corrective lens: The original range of available focusing distances will remain available, but quality will degrade (how significant the change will be depends on the specific implementation, with most adapters only being optimized for the center of the image).

This relationship, when looked at backwards, also makes lenses for a longer register relatively more valuable, as they can be converted to more systems. This was the entire premise behind the ideation of the T mount and the Adaptall series.


Using a mount conversion shouldn't degrade the image quality since there isn't any optics involved, just the mount. Be aware that the older lenses may not have the same level of optics you may be used to on current lenses.

You'll want to make sure you can change the aperture on the lens when you are using a converter since your camera won't be able to do so (since electronics aren't passed through) which make the older F-mount Nikon primes lenses great for these kinds of uses.

  • \$\begingroup\$ Nikon users drew the short straw in this regard: they can only adapt (and focus to infinity) using adapters with optics. \$\endgroup\$ Commented Mar 20, 2013 at 7:38

Nearly all good camera stores will have some old non-AI Nikkor lenses, the 50mm F1.4 is a really nice lens that will be well under $200. But, the non-AI lenses have coupling prong that may prevent it from mounting on your D7000. The F-mount is the same, but the prong can have interference problems with the pentaprism. You really have to try a lens or two with your body.

The second big problem is that modern DSLRs do not have a focusing screen that makes it easy to use manual focus. The old SLR focused wide open and had micro-prism or split-prism focus screens, which would snap when the lens was in focus.

  • \$\begingroup\$ anyone serious about vintage lens photography will get a focusing screen for it. \$\endgroup\$ Commented Mar 20, 2013 at 7:39
  • \$\begingroup\$ Or either shoot tethered or use live view if the camera is on a tripod. \$\endgroup\$
    – Michael C
    Commented Mar 20, 2013 at 14:59
  • \$\begingroup\$ With pre-AI lenses it's not so much the "rabbit ears" coupling prong (Unless you have an overhanging prism - Never had a problem with any of the bodies I've had) as the fact that the subsequent mechanical meter aperture setting coupling uses a tab on the lens mount that engages with a cutout in the back of the aperture ring. Pre-AI lenses don't have this cutout, so the lens can't be mounted properly - the tab prevents the lens fitting flush to the mount.... \$\endgroup\$
    – JerryTheC
    Commented Jul 1, 2018 at 20:27
  • \$\begingroup\$ ... And some AI and AIS lenses have both the cutout and the rabbit ears (there were conversions available, and some lenses kept the rabbit ears for compatability with older bodies). Modern bodies that don't support non-electronic aperture coupling are probably OK since they won't have the tab, and some of the high end film cameras like the f4 had a movable tab you could swing out of the way for non-AI lenses. \$\endgroup\$
    – JerryTheC
    Commented Jul 1, 2018 at 20:30

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