I would say so, although I'm a bit short on hard evidence.

The 55-300 definitely feels much better. It's midway between the weight of the 75-300 and 80-320, and feels much more substantial. The 75-300 always felt a bit plasticky to me, though there was certainly nothing wrong with it.

As to performance, I was never happy with the results I obtained with the 75-300, and I could never put my finger on what I was doing wrong. When I was in Australia last September I took lots of pictures with it at the Sydney zoo, and in the Blue Mountains, and they were generally very disappointing - mostly not sharp enough at the long end, and in anything other than good light tended to hunt a bit looking for focus. In fairness, the light wasn't great, and it was close to wide open much of the time.

Conversely, I was very happy with the 55-300 right out of the box, and delighted with it at the recent airshow. It has a long focus throw, so it takes a while to go from one end to the other, but if you start close to where it needs to be (the quick shift focus, which the 75-300 lacked of course, is great for that), I've had no trouble with its focus speed or accuracy, nor any lack of sharpness that I can't account for with my own incompetence.

Subjectively, I think it's much better, and comparatively very acceptable at the long end, but my impressions aren't at all scientific, and not over the same time periods, so best take them with a pinch of salt.

I have a number of zoom lenses. The DA 18-55 MkI, the FA 28-200, the DA 55-300, and the Sigma 10-20.

With one exception, they all get longer as you zoom to the long focal length end.

The exception is the 18-55, which gets shorter, before getting longer again.

Is there a simple explanation for why this is so?

Yes, it's as I remembered it. I think the thing about this picture is that there's simply too much path. The rest of the shot is fine, but there's that big triangle of flat shingle which has nothing going for it.

I don't think you'll make a winner out of this one. I liked the others though.

Yes, I do accept both these points. I'm not at all suggesting my view has any more validity than any other, just commenting completely subjectively.

Is the original colour version still up anywhere? I'd like to have it as a baseline for comparison.

Not that I know anything about how to do B&W, I'm afraid I don't like Martin's version either. Even if it were not for the halo on the mountain, it's just too uniformly dark and contrasty now, and a relatively benign (IIRC) sky has been turned into something far too aggressive.

But I freely admit that, apart from what I like, I know nothing at all .

Well, neither do I.

But if there's an alternative explanation for the results, than the e-dial is influencing the main flash's output, then I'd like to hear it.

I'm very much a newbie when it comes to flash. I've only just this week realised how wrong I've been doing it all along - it was when an important shoot went horribly, horribly wrong the other weekend that I finally worked out (most of) what a complete muppet I've been.

I think perhaps he isn't.

Never one to shy away from actually testing such things, I set up the K10D and the Samsung version of the AF540 in wireless mode. With the K10D's popup in controller mode (ie where it isn't supposed to contribute to the exposure), I took the following four shots:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1661.jpg[/IMG]

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1662.jpg[/IMG]

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1663.jpg[/IMG]

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1664.jpg[/IMG]

They were all taken at 1/160s, F10 (at which exposure there was nowhere near enough ambient light to see on the photograph).

The only difference between them was that I changed the flash output using the Fn menu: -2, -1, 0, +1 respectively.

Then I redid it, with the popup as master:

[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1665.jpg[/IMG]
[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1666.jpg[/IMG]
[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1667.jpg[/IMG]
[IMG]http://i162.photobucket.com/albums/t244/chris5gd/Technical/IMGP1668.jpg[/IMG]

It's not an exhaustive test, and I only did this one series, with the camera in manual, but the results did bear out the same subjective impression I've had in other modes.

I didn't edit the pictures at all, apart from put them through ACR with the same default settings for each.

Well that's told me.

I hereby apologise for overestimating the intelligence of anyone on this forum that is likely to be misled by George's earlier post.

Well, of course it's still insignificant compared with the total market, since 2% is still only a small proportion of the total.

But it's likely to be very significant for the company that's just doubled its output. There's nothing "lies, damned lies and statistics" about that at all.

No one is suggesting that Pentax is anywhere near as large as Canon and Nikon.

It's better, but I'm still not wild about it.

The main difference is that the stile and wall are paler. As such, the wall draws the eye up to the top right, as I'm sure was your intention, and it's effective enough as a device. But removing the brightness in the background sky (which worked better in colour IIRC) was a mistake I think - it's too bland now, for me.

An interesting exercise, but I don't think it improves this picture enough to make the effort worthwhile.