Great dog portrait. Such a soulful look beautifully captured.

I've come back for a fresh look. I can see the trouble now (I think). The building on the right looks crap compared to the rest of the image, as in very fuzzy. My first Sigma 10-20 was like that, I sent it back and they replaced it with another that was a much better lens. If this is a constant issue I'd certainly send it back.
Sorry not to have looked better on my first try.

I haven't. I do feel the art work would need a different background, perhaps a sheet of dull polished aluminium.
I think whether it works or not will largely depend on the backing material and the choice of frame.

I can't tell anything from your loaded images as they are a very small. My feelings about this lens having owned it for a few months are generally very positive. It has very even sharpness across the frame BUT it is not the sharpest lens I have. In the centre part of the image I think my 18-135mm is generally sharper, but does not compare to the 16-85 on the borders and in the corners.
Can you load larger files or post a link to some larger files. At the size presented the photographs look great.
The boat one, if you focused on the front of the boat surely the background will not be in sharp focus at f4 even at 16mm

Bugs never looked better.

A lovely set, I like all of them.
No.2. The light brings this one to life, brings out the colours.
No.3 Black and Tan. Great shapes, forms and patterns with a strong diagonal.
No.13 It works, it just works really well, well framed composition.

Love them all really.
Best regards
Nigel

Or should that be NPPP Northern Pentax Photographic Powerhouse.

Sounds like the Northern Photographic Powerhouse!

Focus is so last century, time to move on.

I didn't think there would be any interest for this camera and lens here but here's a quick bump with another image taken with this camera and lens.