Thanks John.

So if I've understood this right, F1.4 and 1 second would be EV -1 at ISO 400?

So EV 5 would be 1/64 at F1.4 and ISO 400?

That corresponds with the wiki table - so I'm still unclear where the EV 0.3 comes from.

Of course, EV 5 isn't particularly low light at all. If that level of front focus at EV 5 is typical, it will be a real problem for low light portraits under tungsten, where a wide aperture is desired to focus very specifically on an eye, for instance.

Not a trivial or rarely-encountered problem with the camera at all.

Please could you explain how you calculated the EV as 0.3?

Your EXIF says 1/80 at F1.4, ISO 400.

I may be misreading the table here, but if it's right (and based on ISO 100), your exposure comes out between EV 5-6.

(1/80 at ISO 400 is equivalent to 1/20 at ISO 100, then reading from the F1.4 column in the table).

Not sure I understand this EV thing yet

'Real world' shots are invariably useless for testing focus accuracy. It's virtually impossible to compare like with like that way.

The first thing to do, as JR said, is use a test chart at 45 degrees to ensure that the camera is actually focused where it thinks it's focused. This requires care, to ensure that the camera is pointed accurately at the centre of the chart, and is straight on to the chart. Otherwise, all conclusions are invalid.

Use a delayed mode release so that SR is guaranteed off. Ideally, have plenty of light so that all the worry about camera shake is excluded.

Only then, once you've ensured the AF is adjusted properly for the lens, is it worth proceeding to look at focus over the field of view, ideally at different apertures.

You need a subject with fine detail (brickwork, or a newspaper taped flat to a wall for example), and again, you need to ensure that the camera/lens axis is accurately perpendicular to the subject. Otherwise, if it's sharp at one side but not the other, you can't be sure it's not because the camera's at an angle.

Controlled conditions such as these are hard enough to test reliably, without introducing all the other variables you get with 'real world' shots.

It's not going to win any awards whatever you do to it, but I quite like the original. I like the pastel colours, and I like the sense of depth and distance.

My personal view, FWIW, is that neither the faked light (which just looks messy to me) nor squarer crop do it any favours.

You might bring up the shadow in the middle distance just a smidge (not enough to make it like the brighter foreground - just enough to see a little more of the detail).

Apart from that, why try to turn it into something that it's not? It's a pleasant record shot, of a nice view on a clear day. I think the rocks lead the eye nicely into the picture, and with a little more detail visible in the middle distance, you'd be good to go.

The only other thing is that the hill line is starting to halo a little, so go easy on the sharpening.

I used my 18-55 Mk1 as my main walkabout lens for a long time.

Now I'm using the 17-70 for the same purposes.

It's early days, and I've not done a formal comparison, but although I never had any complaints about the 18-55, the 17-70 does seem subjectively substantially better.

Not that I'd rule out the possibility of the old 4P rule (perceived performance in proportion to price) raising its head, but as the novelty wears off I'll certainly take no prisoners if I find it wanting.

It's all a bit moot now, though - the OP has made his choice.

Yes, no problems with the AF when it comes to hindsight.

I have a Pentax 17-70 which was back-focusing more than the K-5 could adjust.

I sent it in to Johnsons, and they sorted it out, charged me 120 quid.

Top tip: if you're going to join Pentax User Plus in order to get the 20% off servicing at Johnsons, get a written quotation from them BEFORE telling them that you're a PU member.

Do you need a DA 35mm F2.4 by any chance?

Now you're just being silly - you only need intermittent

Yes, that's at least as likely as my two features