It's good to see you posting again, you have an eye for the abstract that I like.

Cropped only...
Same focus point chosen i.e. half way up open door
K-5iis @ ISO1600 1/125 f2.8



K-7 @ ISO1600 1/125 f2.8



K-5iis @ ISO3200

My K-5 opens this far (taken with K-7)



My K-7 opens this far (taken with K-5)

The TC actually does the focusing itself

It is probably the in body shake reduction, nothing to worry about.

The only things these cameras have in common is the size and shape! The difference in performance, noise, DR and image quality, is light years. I have recently gone from a K-7 with which I took in excess of 100,000 photos to a K-5iis and the difference is staggering.

Example on a K-7 (cropped about 50-75%)

I couldn't recommend Sigma's repair service highly enough, it is excellent. I managed to get hol of a Canon version of the 70-200 f2.8 for £100 for a friend of mine that had a failed HSM. I sent it to Sigma, they emailed me with the quote and detailed repair, which was the same as their standard tariff, before commencing any work. We went ahead with the repair and it was returned in pristine condition.
Then, less that 3 months later the silly old duffer knocked over his tripod, complete with Canon 550D and said 70-200, it toppled over and landed square on the front element (on concrete) denting the barrel, knocking the retaining ring for the front element out of alignment and sadly breaking the AF (again) and the lens hood. After I nagged him for a few weeks he eventually sent it off to Sigma for yet another repair, this time the quote came back looking like War & Peace but they repaired it at the same price i.e. the tariff, number 7 £131 (which I believe yours would fall into because the 150-500 is basically the same lens with an extender on the end). Highly recommended.

Look no further than the Pentax SMC f 1.7x AF Adapter. It marries beautifully with the DA*300. It automatically stops down to f6.7. It 's not fully AF but once you dial it close the rest is done by the camera. There might even be one for sale in the classifieds, you'll need to go back a couple of weeks.

Yes indeedy, liking number 4