It was a GX10 (I've now upgraded to a K20D) and it was using a cable switch, not a wireless remote.

I leave SR on for:

Hand-held
Monopod
Tripod with loose ball head or loose gimbal

I turn it off for:

Tight ball-head
Panning head

My tripod is pretty sturdy and with a locked down head and using a remote trigger I'm sure I've seen problems with SR when I've left it enabled.

BTW: Well done for getting the DA* 300mm

I couldn't take most of my hand-held telephoto photo's without SR at 300mm+ as the larger apertures mean I have to use slower shutter speeds than recommended for the focal length.

Yup. Not a cricket (they generally have long antennae). I prefer the focus on the first one. However, the composition of the second is great, although the eyes could have done with being in focus. An interesting angle of view

Don't knock yourself, it's a lovely photo. The lighting and backdrop are great. Would've been nice to have the black-headed gull walking into, rather than out of the frame

Congratulations on both! Only your wallet will be disappointed

I'm not sure there's much difference in sharpness between them, once you stop the Tamron down a little. The biggest things for me are the obvious - weight, auto-focus, weight, SDM, weight, quick-shift focus and, oh, weight.

That said, I guess it depends how you intend to use it. I wanted the DA* to be able to use it as a walkaround lens, and it's definitely more versatile than the Tamron in that regard. If I were mostly going to stay in one spot, then the Tamron would seem an excellent, and cheaper, option.

The owners of the Sigma 100-300mm f4 do seem to like it - I think you'd see a significant difference between it and your older sigma zoom.

Remember, though that it weighs 1440g compared to 1,070g of the Pentax 300mm DA*. Also, the Pentax is weather sealed, has SDM, and has the Pentax quick-shift system which I've found extremely helpful when taking pictures of birds in trees and bushes where the AF cannot cope.

What do you mostly want to take pictures of with the lens?

I ask because I went down the zoom route and found that I was always using lenses at the long-end and therefore compromising on sharpness and available light. For that reason I switched to primes and used by legs if I was too close

The batteries are identical between the K10D and GX10.