You could buy directly from the US - they're ~$360 (£240) as a kit from the main online dealers.

Even after shipping and taxes it should still be a bargain.

The Pentaxforums offer for the 100-300/4 + 1.4x is a very good one, if it had been advertised in the US instead of Thailand it would have sold on day one, I believe.

In Pentax mount?
I haven't sen them since I don't watch Pentax gear on eBay anymore, but I know that they are in general more expensive in Pentax mount than in Canon or Nikon, which is true of most 3rd party (Sigma, Tamron, etc.. ) lenses - and in particular that Sigma 100-300/4!

In my experience the 1.4x/1.5x will work well with this combo, but the AF will be much too slow (and sometimes hesitant) for birds in flights for instance, or fast-moving objects in general.

FYI, I was very surprised to find out that the Promaster 1.7x was also SDM compatible, at least with the K-01 + DA*300 combo (although AF is excrutiantingly slow, but that's mostly the K-01's fault, which is not intended as a "wildlife" body).

I sold the Tamron 1.4x here recently, it didn't really fly off the shelves, despite what I thought was a very decent price.

PM sent

Bump, Pentax 1.7x AF still available.

One sold recently here:

Pentax 1.7x AF adapter £285 shipped

Thanks Duncan, I can say likewise, it was a pleasure to deal with you!

The Tamron is sold pending payment, Pentax 1.7x AF still available.

Hello,

I'm selling two fairly hard to find converters for the Pentax mount:

. Tamron Pz-AF 1.4z MC4

One of only two (with the Kenko 1.5x SHQ) to maintain AF with SDM/HSM lenses.
Boxed with original caps, excellent condition with immaculate glass.

£185 shipped to anywhere in Europe




. Pentax 1.7x AF adapter

Alows you to autofocus with a range of older manual lenses, but works with current ones too (some think it pairs very well with the DA*300/4, for instance).
Comes with (generic, I think) caps, fully functional, only thing worth mentioning is a slight coating imperfection on the very outer edge of the rear element, which I doubt would affect picture quality.

£255 shipped to anywhere in Europe