Ask your wife if she would rather your hobby is going down the pub every night drinking beer and chatting up other women

I must admit to being in the same boat, I was looking at the DA* 300mm and DA* 200mm but could not bring myself to spend the money on something that is "only a hobby" and to be honest having only been participating in it for only 9 months anyway could be short lived.
I therefore bought myself a used Pentax F* 300mm f4.5 and Sigma 70-200mm f2.8 for the price of the DA* 200mm knowing that should I want to I will get back what I paid for the lenses with ease.

Saying that I am now looking at either a Sigma 180mm macro (which I will NEVER find used) or a new K20D body ... because I saved on the lenses

Its an excellent lens, you will need a PK/A mount if you want to use the A setting on camera or just the PK mount if you dont mind doing it via the lens itself.

Clinton Cameras had it for £435 before cashback but it seems to have gone up now.

I have the Sigma 2X (£99 from SRS) and its excellent with my Sigma 70-200mm f2.8 and Pentax F* 300mm f4.5 but it will only manual focus with the Pentax lens.
It will not fit many lenses though as the front element of the Sigma converter sticks out (unlike my Tamron 1.4X units) and so you need a recess on the lens you are fitting it to.

Easiest way to explain is male to female.

The Tamron 1.4X MC4 AF unit will work on everything and is actually pretty good.

I have a spare that I would be prepared to maybe let go but to be totally honest if I did not have the Tamron I would probably wait for the Pentax version.
Saying that, it depends on how long you are prepared to wait for it to be released.

SDM does work with the Tamron MC4 1.4X though.

I went for an older Pentax F* 300mm f4.5 which works nicely with the Tamron 1.4 Teleconverter.
It also works well with the SIgma 2X DG EX Teleconverter I bought for my Sigma lens (although in manual focus only).

These were taken with K10D in AF.C mode.

Faster lens and loads of light were probably a big help though ...

I never shoot wide open, prefer to crank it down a stop as I find that I get much better sharpness when I do.

I got this Xmas day with my Pentax F* 300mm f4.5 (I was going for the Sigma 100-300mm until this came along).
I did do a couple at f4.5 but they were pretty soft but at f5.6 things get a lot better.
That is approx a 75% crop, maybe a little more.

Well I'm back for good in March, are you near retirement yet?

Seriously though, I really enjoyed doing these .. if you weren't so far away from me I would ask if I could tag along one day when I return.

Thanks

Thanks