A lot of people seem to comment on the difference. It would be interesting to see two identical shots taken with sensors of both types for analysis.

A nice shot and perfectly level. I don't think it needs any additional processing. If you 'fixed' the verticals it would look like the bannister sides were slanted up.

I agree. It's possible this is on the side of an image, perhaps a line of K3's in different colours. Also think about the amount of work to photograph a separate lens at the right angle to paste exactly on a camera body photographed at an awkward angle. Also matching the shading, noise, grain etc.

Who'd bother!

That's a K5?[/quote]Sorry it was on the same page as the K3 pic and I didn't look properly.

If it's aimed at pro's I don't think looks are going to matter, performance is more important.

Looks good to me.

I've got a variety of old Pentax primes and they all give good results, my SMCA-28mm F2.8 is particularly good. As said already, condition is important, I'm fortunate enough to have owned all but one from new.

This might do what you want in Linux and it's free.

http://lightzoneproject.org/

I've used the Windows version and it runs ok but not had enough time to explore the s/w fully.

Browsing this thread made me think maybe Pentax should re-manufacture some of their old A series lens, perhaps with a 'Classic Pentax' moniker. Manual focus of course as before. There would be little in the way of optical development costs as the designs already exist. I imagine they'd want to swap the metal bodies for plastic, nothing new in that these days. The originals are already purchased by other brand owners and sought after by many Pentax users. If optical quality was the same, it could be a nice little earner for them!

Impressive close ups, especially the second one.