On order from a supplier in the Amazon market place.

I nearly passed out when I saw the new price of the book, but one of them had one, allegedly in good nick, for 7 quid.

Worth a punt, at that price. Thanks again.

Ah, found it.

Well well. Another little gem buried in the custom menu whose function I hadn't appreciated.

Thanks chaps.

Erm, just in case you're not being funny, and I'm being even denser than usual, what setting is this?

Fair point, John. I'm sure it isn't intended to be mystical, and what might be very straightforward to evaluate subjectively if you have a lot of experience may very well not be if, like me, you have a lot less experience.

The thing is, we have a lot to contend with. We have the cameras, the lenses, the editing, and the technique, to say nothing of the monitors, and our own eyesight.

Separating all these is not easy, and mostly what I see when people publish so-called test shots I find intensely frustrating, since there's so little attention paid to experimental rigour, and often they prove nothing at all. This drives me nuts, and you're probably detecting some of my frustration coming through. It's certainly not aimed at anyone in particular.

Indeed they certainly should be, especially if you have to lash out £1000 or so to find out. Which is why I wish there was more objectivity in the game.

I completely take your point and George's that there's tons more to it than a bit of pixel-peeping. But pixel-peeping, despite the pejorative use of the term around these parts, is comparatively very easy to do, and it eliminates some of the more obvious problems with the equipment, provided that it's done properly. Which after all, isn't that hard, if you're careful.

Once the pixel-peeping is out of the way, there's no undercurrent of doubt in the capabilities of the equipment, which frees up the mind marvellously to get on with the real job.

Thank you, I'll see if I can track it down. Much appreciated.

Not disputing this, but...

This is all very well, but they're all virtually impossible to compare with other lenses, or even reproducibly with the same lens, since conditions vary from one moment to the next, as you indeed pointed out to me when we were talking about comparing my 400mm lenses (which I haven't forgotten).

I think it's very important to know whether a lens is sharp or not, and at which apertures. Otherwise it's back to all this mystical subjectivity, and it's impossible to distinguish whether the Emperor has clothes on or not.

What are we supposed to be looking at here? Reflections of the lamp posts, or the lamps? Are you talking about the curve of light splodges (for want of a better word) on the ground next to the person in the frame?

If so, what's its significance. Sorry if I'm being dense.

Maybe the focusing is silent because it isn't doing any....

Well.

The first of these is based on Amoringello's IGP6624.jpg - the Pentax 18-55 at F5.6.

The second of the two, the one you say is crisper, is his IGP6620.jpg, the Sigma 18-200 at F5.6, unchanged by me.

In the originals he showed us, the picture from the Pentax lens (ie the first one here) was extremely dark in comparison, making it very difficult to compare the two.

So I tweaked the brightness, contrast and saturation, only of the Pentax shot, until it looked as nearly the same as I could make it without spending hours on the task. I didn't apply any sharpening to either, of course.

As you say, I think the focus points are different, which makes it very difficult to compare, and hence a test of only limited usefulness.

Personally, I think the only thing that can be concluded from the test shots is that it's not at all obvious that the Pentax is the better lens.

Thanks for doing the comparison!

I was afraid you'd say this. With all the differences in equipment and perception from one person to another, it becomes very hard for the less experienced such as myself to tune into to what it is that the more experienced are actually talking about.

Let me press you a little, if I may.

Which of these pictures do you this was made with the better lens, in terms of the characteristics you mentioned above, and why? Please don't look at the EXIF, nor at the earlier pictures on the thread - nor at the filenames !!





Edit: sorry, I've rephrased the question slightly.

Well looking at the crops of the bottles, say for the 18-200 and the 18-55, I'm not seeing a significant difference in sharpness.

And going back to the bunnies at F5.6, I don't think it's at all obvious that one is sharper than the other (once they've been made much more nearly equal in saturation and contrast).

So I'm not clear exactly what you mean by "degree of quality".