Tamron Adaptall 2 Mount for Nikon

I was given a Tamron 70-210mm zoom lens by my son-in-law, who got it for free. It has a Pentax K mount adapter, and I own Nikon Fs. I need an adaptor which will allow the diaphragm to be held open until the exposure is made (a la the standard Auto-Nikkor lenses). The lens itself seems to have the standard auto-diaphragm pin protruding from the back.

I have had a preliminary look on eBay, but I'm not sure which Tamron adaptor I require. I don't need any electronic coupling, or any meter coupling at all, as my Fs have the plain, non-metered prisms. One auction stated: ..."Noelectronic or manual linkage. Allows lenses to be used in stop down Manual focusmode only."

Should I be looking for an Adaptall 2 adaptor, or anything which is suitable for the AI lenses? Any input on this would be appreciated; I don't want to buy an adaptor which will allow the lens to work only in a manual diaphragm mode.

For the F you need any Adaptall 2 Nikon mount. I believe some such mounts don't have an AI metering tab, but your F doesn't use it anyway. The AI ones are generally preferable in case you get more modern (post-1977) Nikon cameras, but work the same way as the non-AI ones do on your F.

There are genuine Tamron Adaptall-2 mounts, and there are Chinese knock-offs. The Chinese knock-offs will not preserve auto-diaphragm action - you are always going to be looking through the lens at whatever the aperture ring is set for. Get a real Tamron Adaptall-2 mount. Even though you don't strictly need it for your purposes, f I were you, I'd get one with both a meter prong and AI-coupling. Those will work with any Nikon Manual focus body.

BTW, one thing I've noticed on ebay recently is that it might cost you very little more to get the mount actually attached to a lens, then to get JUST the mount itself. So you may be able to get a decent lens along with it for a bargain price.

Which Pentax mount is on the lens? The KA mounts are quite popular and expensive. KEH.com sells the used Nikon mounts for $15 or so.

I wish they sold them for that cheap. I bought a 60-300 Tamron SP a few months back without mount, tried KEH first, and then searched eBay on a regular basis for a reasonably priced Adaptall II mount in Nikon AI. It took a while and was frustrating to boot. Nikon AI has to be the most in-demand Adaptall II mount, by far. I was about to buy a 70-210, as Doug recommended, that had a Nikon mount attached just to get the mount, when I spotted a buy-it-now that had just gotten listed, and for a decent price (for a change). Think I paid $20 for it plus another $10 shipping (it came from Australia), and was glad to get it for that price.

Just a few days ago, I spotted another 60-300 on eBay, which had a Canon FD mount attached. Plus the hood and the original case were included. Mine came with neither. The bid price was really low, and there was only a couple of hours left with the auction, so I figured aw-whatever, and bid on it. Got it for $25, and it was shipped to me for $15. It arrived today -- woot! So, for $40, I got another 60-300, plus an FD mount (I have FD cameras, so that's cool), plus the hood and case. At the same time as this auction, somebody was selling just the 60-300 hood for $15 (and I was thinking about getting it, too!), and I'm sure FD Adaptall-II mounts were selling for $15-20 as well. So, this tactic worked well for me. All I was after was the mount and the hood, and I got a lens and case for no extra charge.

Best,
Michael

Wow Michael, I just went and looked and your right, the prices have more than doubled. Weird.

Not really weird to me. The scarcity of Adaptall-II mounts in Nikon mount tells me a few things: 1) there are still a lot of manual-focus Nikon users out there, and 2) they like Tamron. If they didn't, the mounts would be plentiful. Instead, what we appear to have is a hard-core group of Nikon MF users who buy and hold their Tamron gear, which keeps the availability tight. Thus, when an Adaptall II mount occasionally hits the market, there's sufficient demand to drive up the price. I suspect that the reason why this situation is less true with other mounts is that, as a percentage, users of other camera systems have moved over to autofocus, abandoning their MF Pentaxes and Minoltas and Canons (which is really too bad), and haven't looked back.

The fact that Nikon's F mount is backward compatible for like forever is likely another reason. Pentax's K-mount compatibility may account for a shorter supply of K-mount Adaptall-IIs, but to be honest, I didn't notice them to be particularly scarce when I was looking hard.

Best,
Michael