I am staggered at what is apparently being "seen" in the examples we've seen, and how out of context it all is. It certainly doesn't make sense to me for something like this to outweigh everything else about a camera.

As for pixel-peeping, I think it's down to why one does it.

If it's because the pictures you're taking aren't satisfactory, and you don't know why, then it's a legitimate part of the learning process.

Six months ago, for instance, I didn't know enough to be able to say with confidence that two out of my three moon pics from last night are out of focus, despite the camera saying they weren't, and that that (rather than anything else) is the problem.

Now I do, and it's only through much experimentation and much fiddling about with 100% crops, that I've acquired the technique and the experience. It's very limited experience, compared with others here, but it serves its purpose. And the pixel-peeping I did on the way was necessary, and very valuable.

I can't see it either. Not on the red lettering. He's not talking about CA in this case, though - there's no significant evidence of this in any of the pictures he's having us look at. The CA reference was in the Photozone.de review of the Pentax 16-45, and I've yet to see any evidence either way for that.

Although I'm probably more of a pixel-peeper than George, I too think this is all way over the top. There's insufficient evidence, in my view, to attribute these extraordinarily marginal pattern deficiencies - if that's what they are (and I don't think even that is established unequivocally) - to anything specific.

If Arto is troubled by them, he should do his own tests, so that he can be certain as to the influences of all the variables, and make comparisons with other cameras too. The impartial science needed for that would have to be at least as good as his eyesight.

If it turns out that the effect is real, perhaps he should be buying a camera with a price tag measured in thousands, not hundreds, and similarly the lenses. At least if you spend that much money there's a strong psychological barrier to seeing deficiencies, so maybe any problems wouldn't be so troublesome.

Forgive my suspicious nature, but I'm not entirely convinced that this isn't all a big wind-up, with Arto coming back shortly saying "Ha, ha, made you look".

You want to see some chromatic aberration? Here you are (top row):

http://i162.photobucket.com/albums/t244/chris5gd/Technical/56crop.jpg

However, be aware that the lens that produces all that terrible CA also produced these:

http://i162.photobucket.com/albums/t244/chris5gd/Public/IMGP2694-m70-1-pb.jpg

http://i162.photobucket.com/albums/t244/chris5gd/Public/IMGP2683-3-M70w-pb.jpg

It's visible in the latter shot, but the lens was nearly wide open, and the places where the CA is visible (top left corner and twig above the robin - not the dirty great vertical branch behind him) are out of focus anyway.

I take your point. But I'm invariably finding that for the picture I want, at the moment I want it, in the place I'm forced to be, the lens isn't quite long enough, or quite wide enough, or quite fast enough.

There's never quite enough light, quite enough space behind me, quite enough time to get further away...

... so I'm forever wanting just that little bit more than I have, and further, wanting more at the boundaries.

I'm well aware that my abilities are woefully lacking in the part of the envelope where there's the time to set things up, or wait for the light to become better. But any of my lenses is good enough to produce something beyond my current abilities in that regard, so the question of "what to buy, and why" doesn't arise.

Even on a big print, wide open, at 16mm? At the edges?

I want one... 'cos I really like the idea of 16mm... but only if I can really use it there, if you see what I mean.

Edit... It's a funny thing, this digital lark. But I really think I should expedite getting hold of a scanner and starting to go through all my negatives to see what I was happy with in the old days. I've gone straight from film (ME Super, mostly) with very mediocre glass, to the K10D, with the potential for far, far more demanding criteria.

The idea of a big enlargement of a tiny piece of a negative, to see whether there was any CA in the corners, would never have occurred to me.

How things change, eh?

But I do see much more these days. Even when I'm not looking for it. Tell me that's a good thing, please....

Agreed, it's an unfortunate choice of words, and it's a shame he didn't quantify the "very pronounced CA" he says he found.

Has anyone else in these parts with a 16-45 noticed anything about its CA that would justify a description of "very pronounced", at the wide end presumably?

Well, I'd agree that "bug" is a bit pejorative, but I think you should read it in the context of how he elaborated:

"The only real problem are very pronounced CAs"

Presumably the CA he found was enough in his opinion to refer to it as "very pronounced" - relative to other lenses, or indeed what he was expecting given the superior overall quality he describes.

If it's true, then it's perhaps an aberration, if you'll pardon the pun, rather than a bug.

But these "tests" that you sneer at, are the only thing that allow for objective comparisons. The rest is just people's opinions, and these are notoriously variable and unreliable. If I'm going to spend several hundred pounds on a lens that I'll probably have to order, sight unseen, then I might want to know (for example) how much CA it's got, in what circumstances, in comparison with other lenses that I might be considering.

I agree with you that the reviews are often dreadful, but that doesn't take anything away from the value of an objective assessment of the characteristics that are measurable.

I would have to disagree with you here.

It wasn't until I went much higher than 100% that I eventually saw the effect in the curlicues that you mentioned. My eyesight is pretty good, and although my monitor isn't especially bright, it is pretty sharp.

I'll see if I can see it on a newer monitor.

To be sure of this effect, though, I'd want to see it reproduced on a flat subject, not one curving away, and in a comparison where the magnification in each example was the same.

In fairness, photozone.de is very complimentary about the 16-45, and indeed about the K10D generally.

It says:

So the only fault they describe is the CA, which either is present, or is not. It either is worse than other lenses, or is not. If it is, then of course maybe it's the individual copy.

Either way, this paragraph doesn't read like an anti-Pentax diatribe.

I think we need to be careful, if we want to keep the moral high ground in respect of comments on the quality of Pentax kit, not to appear to be showing as much pro-Pentax bias as others show anti.

I don't think so. What he's referring to is not a general blurring of any kind.

And it's surely inconceivable that they did the tests by pressing the shutter release with their finger.

If they used any kind of "mirror up" option then the SR is switched off by the camera.

Ok, well I saved both pictures and looked at high magnification (much higher than actual pixel sizes) in PS3. I think I can see what you mean on the curlicues.

As I say, the magnifications are not the same in the K10D and 30D crops, so the comparison is not really like with like.

Assuming that it's not an artefact of whatever techniques were used in the creation of the graphics files on the DPR site (who knows what they did converting RAW to the JPEGs shown), and that it's got nothing to do with the different magnifications, then if this is really more important to you than everything else about the K10D, then maybe you shouldn't buy it.