[MrA]

In my exploration of second hand lenses available, for use with my (new) K100D Super, I keep running into "adaptall" and "adaptall 2" lenses. And keep hearing things about how they need an adaptor whatever system you use. But I can't seem to find a summary page on this. Even adaptall-2.com doesn't have an obvious page detailing adaptors

Do they work properly on pentax k mount cameras? Any words of wisdom on the subject? Adaptors to avoid etc (as per the m42 adaptor).

For reference, I'm looking at old lenses because I'm most definitely a student on a budget.

[Nesster]

Thanks for this question - I was going to write an appreciation of the Tamron Adaptalls.

I have three of the lenses, and each is excellent for its category. The SP 35-80 CF is still up there in performance relative to current mid zooms. The SP 90 2.5 macro, it just resolves and has color very much like the Pentax 70mm, only it focuses to macro and doesn't have CA badly. And my latest score is the 80-210 3.8-4 model 103A, which I've taken an immediate liking to. All these feature close focus which does come in handy for me.

All the Tamron Adaptalls I've used have excellent performance characteristics and are well built relative to aperture blade springs etc - things that e.g. Olympus and some M42 mount lenses aren't. But they also have their loose bits, the two zooms both have a bit of a clonky feel to zoom/focus at one point or another. I'll probably keep picking up more of them, when I see bargains. (And should I ever by 'accident' end up with a Fuji AX or Minolta or Nikon body, I'll have the lenses all ready to go)

Now the bad part for Pentax users: the pentax adaptors are relatively rare and therefore tend to be expensive. You essentially have a choice of 3: The KA which makes the lens behave like a SMC-A. The K, which makes it behave like a SMC-M. And the M42 screw mount.

I've been lucky to get 2 KA mounts. Otherwise I've accumulated: OM, Nikon AI, Minolta, Fuji AX... I might have another one too, somewhere...

Once you have a Pentax mount Adaptall, the whole Tamron game becomes easier - that last lens I bought came with the Fuji AX, which I promptly swapped for one of my Pentax adaptalls. If lucky you can get the adaptall you want with the first lens you buy.

Here's the adaptall-2.com brochure on the mounts available:
http://www.adaptall-2.com/brochures/SP_and_Adaptall-2_1979/page17.jpg
There's a print quality scan of this - look for the brochures page.

Here are instructions I scanned a while back:


Adaptall instructions on Flickr - Photo Sharing!

[Nesster]

Looks like Tamron still makes a "Fujica ST" adaptall-2 mount, I think this is otherwise known as a M42?

[MrA]

Thanks for the information Nesster. I trust since they can work with any system by design, there are no 'infinity focus' issues that you can otherwise get by messing around with lenses and different mounts.

Why are they no longer made, then? Surely all those 3rd party len-makers out there, sigma etc, who make their lens with a canon, nikon, pentax, 4/3 mount, would do well if their customers knew that it was a simple matter to switch the mounts if ever they jumped ship. Was there some technical limitation or something?

[Nesster]

The main reason they aren't made is AUTO FOCUS. Every make has its own parameters. So Tamron, Sigma et al make the same basic lens in different mounts, they have to.

[ryan s]

Like has already been stated, the 3 mounts make the difference in how you use the lens. The M42 requires stop down metering in M + green button or Av modes, like other fully manual lenses. The PK allows wide open focusing, and temporarily stopping down to meter in M + green button. Then the PKA allows wide open metering in Av mode (like modern lenses), but still works in M like the PK.

I have all three and 2 PKAs, and prefer to use all my lenses' aperture rings in M. The M42 is sort of convenient when you are using other screw mount lenses and don't want to fool with the M42 -> K adapter.

I would suppose it comes to availability, price, and preference. Get the one you would rather use