G'day and welcome to the forums. I think the question you asked has been answered already, so instead of throwing my 2 bob in as well I thought I'd share my experience in two sensor sizes with a DA lens.
These two images were shot using the same DA 70mm f2.4 LTD lens but one image was captured on the K5, the other the K-1.
This is a lens specifically optimised for a sensor like that in the K5, but as far as I'm concerned it's a great lens regardless of the sensor size. Sure the field of view is wider on the K-1 and it vignettes wide open but so do my Zeiss lenses. And it's a look I'm quite partial to so it sits in my bag with the six Zeiss lenses as when it's the right tool for the job that's the lens I pick.
Tas