Hi guys.
I'm just browsing eBay & a thought occurred to me, is there any well to tell the difference between say a Nikon fit lens from any other fit just by a photo.
The reason being is a lot of ebayers list lenses they don't know anything about do it would be handy to know.
Thanks in advance
Rob
pre-AI has no 'slot' around the edge of the mount for the aperture read lever.
pre-AI *nikon* brand lenses only have one set of aperture numbers
AI have the slot for the read lever, Nikon brand AI will have 2 aperture number rings.
AI-S nikon brand lenses have only a single aperture ring IIRC, but the slot for the read lever (all post-AI lenses should have this slot)
AF and beyond add the electrical contacts, the number of contacts will allow you to somewhat tell what features/sub-era are present, but only to a degree - ie, if there are only 5 contacts, there's no way it will be VR or -D.
It can be hard to tell on ebay unless there are good photos of the side and bottom of the lens (to see the aperture rings and read lever slot)
It can also be especially hard with 3rd party lenses, as they didn't always use 2 aperture rings, like Nikon did, on AI era lenses.
The AI 'aperture read lever slot' is the biggest give away for a lens to be compatible on a digital/modern body, even if a lens is AI it's still going to work, just without all modes/metering options.
Edit:
Here's an image that has the edge of the Aperture Read slot and the Aperture Read pin (which the Aperture Read Lever on the body pushes up against). This is on an oldish AF lens, which has the 5 contacts for a basic AF function, but nothing more fancy.
Aperture Read items on Nikon AF lens by
nikki_archibald, on Flickr
Edit #2:
In terms of telling a Nikon fit from another...
The most common non-Nikon fits you're likely to run into are going to be M42 (which should be obvious, as it's not a bayonet fitting but a screw thread), Pentax K, Olympus OM, Canon FD, Canon EF and Minolta.
Of these the biggest problem to tell from a Nikon is probably the Pentax K, the oldest of which are a fairly simple 3 tab bayonet, much like the pre-AI nikon mount. But with these if you get one confused for a Nikon pre-AI, then reject it because it's pre-AI, you're still ok. Newer K(A) and later K mounts have electrical contacts, but unlike Nikon's they're arranged around the outer metal part of the mount, and recessed. K(A) are thus easy to tell apart.
FD Mount is easy to tell from the large metal aperture (edit, not setting, the setting tab is recessed in a groove) read tab on the piece of metal surrounding the rear element. It sticks out about 3mm and is rectangular, quite distinctive.
EF mount is easy to tell from the contacts - while they're around the rear element as with nikon, they're a different pattern, and usually rectangular contacts, often recessed ever so slightly with plastic seperators.
OM looks a lot like a FD mount, but has 2 tabs (read and set) for the aperture, and they're on the surround for the rear element.
Minolta/Sony mount has changed some over the years, the oldest (manual) however are the closest looking to the Nikon mount with a standard 3-tab bayonet. However, aperture setting is acomplished by depression of a pin (much like M42), rather than rotation of a tab, and thus the aperture pin becomes an obvious distinguishing characteristic. Newer AF and on lenses have rectangular contacts, much like the EF mount.
