Perhaps the question we should be asking is why do so many images we see have sloping horizons? Even magazines and books have plenty of examples. Does no-one notice? :

We're all speculating, of course. Sort of related to this was a question in last week's AP which asked why manufacturers don't put levelling lines in the viewfinders of their DSLRs. We could then all avoid those sloping horizons!

The answer is probably not the one given in AP, but perhaps more to do with the accuracy of positioning of the viewfinders relative to the sensors. If there were lines provided then they would have to be 100% accurate and that would no doubt cost a lot more. As it is, there is probably some degree of error that is generally acceptable and, after all, we can always put a brick under one foot.

But the CCD is not fixed anymore. Is this a possible cause of this new situation? Maybe the SR system means that there is more room for error than there used to be.

I wonder if there has been a test made of absolute sharpness vs reduction in camera shake or whether there has been a trade-off.

It's fascinating how these new problems crop up after years of it never being mentioned. If it's a problem with Pentax then I wouldn't be surprised if it isn't a problem with Nikon and Canon as well.

Fortunately my focusing seems fine. It would be IMHO intolerable to have to contemnplate constantly re-adjusting for different lenses. Any fault like that and it would be straight back to Pentax for a proper fix under warranty.

Published lens tests do show significant variations even at f22.

And you'd have been right.

There may be no perfect lenses, but there are plenty of perfectly good ones.

Diffraction limted yes, but there are huge variations in performance levels between lenses. Diffraction is not the only consideration.

That's odd, but maybe you have a superb 18-55mm and a below par 16-45mm!

No lens delivers its best sharpness or resolution at f22 because of diffraction effects. The best apertures are usually around two or three stops down from open aperture, often f8 or so. The better the lens the more dramatic the fall off at f22 will appear to be.

By all means submit a report.

I like the last one best. It really suits the technique. It's hardly a natural looking shot, but I think it's really good. Well done.