Setting aside any EU legislation, which hasn't all been adopted by the UK, you still have a case to argue if a good fails within 6 years of purchase and it is clear that the failure is due to an inherent fault. In this instance there are numerous reports of the aperture block failure to demonstrate it's an inherent problem.

Personally I find a quick letter to the manufacturer, giving them 14 days to respond normally does the trick, with a promise of action via the Small Claims Court if they fail to resolve the matter to your satisfaction. Only once have I needed to start the Small Claims process, which I copied 'them' into. They contacted me by return and we agreed a settlement.

That's my problem too. I'm heavily invested in DA and DA* lenses, most of which will only perform in crop mode on the K1.

The value of DA and DA* lenses seem not surprisingly to have taken a bit of a dive given the number of people who have sold them off as part of a move to the K1.

The Ki and associated D FA lenses are heavier and in many cases more expensive than their DA and DA* counterparts.

I don't want to carry heavier kit - I've bought a K-S1 and all the DA Ltds and some high-end compacts to give me lighter weight options over my K20D, K5II and K3II.

None of my spending on cameras and lenses has improved my poor picture making technique and 'eye', although my photos are all sharp, well exposed, etc .

My conclusion is to let the K1 pass for now and spend my money on good food and drink!

Welcome to the Forum.

Your equipment list suggests you might be a Pentax fan? 😉

My reading suggests that a number of owners found the lens soft at the long end, but noticed improvement when stopped down to 6.3 and 8.

Equally, a number say it's very sharp wide open at the long end, so lens variation, technique, who knows?

It's a rare lens that performs really well wide open. Most lenses have their sweet spot a couple of stops down.

Your lens tests look in focus but soft. If you can, maybe try another copy of the lens, or the lens on another body?

Bump

Although the opposite seems to apply to a Panasonic LX100 I bought recently, which is light and takes 15 minute clips in 4k.

Oh well, if it's only a £256 saving....

Worth joining to get c£550 off the price of the 560?

And now I've looked again, there are a few cameras/kits there too. All notionally used, but I've often found Amazon's 'used' is damaged packaging only.

And there are a few Pentax items available. Saw a few lenses - Pentax 50-135 and 540 - and a Tamron, but didn't see any bodies.

AF fine adjustment with a zoom is always a compromise, but in any event it should always be done at the widest aperture.

With a zoom, either (a) set af adjustment at the point in the zooms range that you use most often, (b) determine what's needed at the min, max and middle of the zoom range and average the adjustment setting, or (c) determine af adjustment at various main focal points throughout the zooms range, note the adjustment required at each point and adjust the setting in real time once you know what focal length you require.