Careful here. With pre-A lenses, Manual works fine provided you meter wide open and calculate your own shutter speed at the aperture you want to use.

And in aperture priority, not only does it meter wide open, but it also takes the picture wide open, regardless of what you set the aperture to using the aperture ring.

Page 210 in the manual.

So not quite fine, but workable

Recommendation: stick to A-series lenses and later.

Thanks John. My invisible one isn't mysterious enough then...

My problem is more that I have too many candidates this week. Like 'what on earth was I trying to achieve with that.... now there's a mystery'.

BTW, I completely missed Mac's beta-test suggestion above - I must have scrolled right past somehow.

Not at all my intention to steal anyone's thunder - sorry

... just two great minds thinking alike, hopefully

I wouldn't disagree with this at all. Lots of lenses are a bit soft wide open though, which is why I referred to "particular" softness. And there's a little PF too, if you really work hard to achieve it.

But compared with the unpleasant PF that the Tamron 70-300 is prone to, for instance, the Pentax kit lens displays a negligible amount.

So sure, it's a budget lens, there's some softness wide open - and if you inspect the high contrast edges at 100%, you can sometimes see a bit of purple.

But IMO there's not enough of either to remark on it as a problem, on the K10D anyway.

Here's a thought.

In my nearly two years hanging out on this forum, I've been consistently impressed, and frequently amazed at Matt's apparently inexhaustible supply of technical knowledge, and, more to the point, patience.

He carries on being prepared to answer questions helpfully and politely, long after lesser mortals such as myself start grumpily mumbling things like 'RTFM' ...

So, how about we give something back to the guy.

I'd be prepared to

a) pay Matt in advance for the book and
b) offer my services free as proofreader, or beta-tester, if you like, prior to the first 'words-only' edition.

It might be helpful for him to get feedback on the way, as it were, on readability, errata, etc.

Obviously I have a slightly vested interest in seeing the book's material early, and I wouldn't deny that I'd be pleased to have such a 'heads up'.

But it's not my primary motivation. I'd be happy to pay up front in any case, even if he doesn't want proofreaders.

To my mind, it would be a bit like paying in arrears for his outstanding contribution to date.

I don't think it's usual for the 18-55 to exhibit much PF on the K10D, nor any particular softness. I use the kit lens quite a bit, and I've seen neither of these problems.

Spend £20 on the wireless remote, and use it to release the shutter when the camera is on the tripod.

Then, SR will be off, regardless of the SR switch position, because the camera switches it off in those (and all other remote/delayed situations), as the manual describes.

I did indeed. Scroll up to my earlier post on this thread - I included a link to the thread where I described my tests. The glitch is described in that original post.

I've had exactly the same symptom once since - photographing fast jets at an airshow, and that was all hand-held. Although SR was on at the time, it would be very premature to assume any connection.

That's ok, Don - whenever you wibble on about SR causing blur in hand-held shots, I assume you've had another one...

But I am curious how you conclude that my None of that series of experiments was done hand-held, it was all on a tripod. So it would be quite wrong to conclude anything about SR's usefulness for hand-held shots at all.

In my experience, SR hand-held is fab, and enables me to do things I'd never have been able to attempt.

This, for instance, was hand-held.

18mm, 0.3 seconds. That's at least three stops better than the rule-of-thumb. I used to be able to get 1-2 stops better than the RoT in my film days, with a lot of elbows-into-the-side, breathing out, kind of thing, but not 3.

I guess it might have been sharper still with SR off...

I can see your arms waving as you say this, Matt.

Is this based on any actual information, or are you speculating a bit? Rounding errors don't always make a significant difference, nor do they always make the result larger.

Has the effect you describe actually been observed in any real situation?

Specifically, where the amount of shake induced by the manual release required to achieve it has been shown to be smaller than any additional shake alleged to be caused by the SR?

Is it available? I searched, but everywhere listing it seemed to be out of stock.

The thing is, actually being able to go to a shop and purchase an item, new, is an advantage. The Pentax range has been woefully lacking for ages, but now, finally, it seems as if things are coming good.

Having to scour eBay for rare bits of kit has been a requirement for Pentax users for a long time, and it's probably become something of a habit for people. But for the brand to compete, it needs to become more commoditised, and there are signs that it's happening.

There are more lenses now than you can shake a twig, if not a stick, at, three current cameras, including entry-level, four flashguns counting the new ring-flash...

And the more Pentax expends its range, the likelier it is that the third parties will pile in, Metz, for example, being a recent case in point.

It's all good. Except for people wanting to sell old gear, of course.