Hi Ron,

I have this lens and I am quite satisfied with it. It is said to be a bit soft wide open on the long end but I doubt that somewhat.
As this has been discussed before, here are some sample pics with 100% crop in the pic:

[IMG]http://i156.photobucket.com/albums/t5/Prieni/IMGP5817.jpg[/IMG]
A5.6@300, 1/500 s, 200 ISO

[IMG]http://i156.photobucket.com/albums/t5/Prieni/IMGP5806.jpg[/IMG]
A5.6@300, 1/750 s, 400 ISO

[IMG]http://i156.photobucket.com/albums/t5/Prieni/test70_300.jpg[/IMG]
A5.6@300, 1/1000 s, 200 ISO

All with my trusted *istD. As far as I remember (these are from January 2007) I did not sharpen (at least for the 100% crops) these pics.
While it certainly isn't the sharpest lens around I think it's good value for money...

Hope this helps,
Prieni

Edit: Forgot to mention that, of course, with smaller aperture the sharpness does get better.

For you here's a shot with a helicopter in it (honestly!):
[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP2878fc.jpg[/IMG]
Sigma 70-300 DG APO Macro @ 70 mm.

First one is great, shame that the bright parts of the cloud are blown. The slight tilt and halo above the crest have been mentioned already.

Second one is a fantastic shot. It got me fooled for a moment, thinking that this 'stone rim' is horizontal.

I like the perspective in the third, the contrast is a bit too much for me, though. Looks like the horizon isn't quite straight on that one either.

On #4 I agree with our arachnian friend...

Nice collection of shots!

Thanks all for looking and commenting.

Martin: It is a fine balance between getting the oomph and overdoing it. I guess I erred on the side of caution here because there was a lot of haze in the originals. If you "see the haze lift" it does blow you away at first and you think you might have overdone it. For a few of the shots I have even decreased saturation. Still, when I look e.g. on the bottom part of the third shot it seems still o.k. (have to say that the greens and reds are striking in reality).
After your comment I looked again and I see what you mean. Could be that they now look more realistic than reality

Darkmunk: I will shortly get to some shots that have a helicopter in them (I doubt that you would be able to make out single people standing around). So watch this space...

Prieni

Here are some first impressions from our trip to Kaua'i. I don't know if these images convey the grandeur of the landscape or if I'm fooled by my memories (if the latter, go ahead and say so, otherwise I might continue to bore you with shots from this trip...).
Here you see some of the famous Kaua'i red dirt:
[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP2790fc.jpg[/IMG]
Sigma 70-300 DG APO Macro

This somehow reminded me of Toblerone chocolade:
[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP2793fc.jpg[/IMG]
Sigma 70-300 DG APO Macro

The next two are views into Waimea Canyon:
[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP2815fc.jpg[/IMG]
Sigma 105/2.8 DG EX Macro

[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP2816.jpg[/IMG]
Sigma 105/2.8 DG EX Macro

Well, you certainly didn't come home empty handed. Marvellous shot, works well for me. I would perhaps crop a bit off the bottom.
The second shot really is necessary to appreciate how tiny this poppy is (or to appreciate what immensely big hands you have...).

Prieni

Interesting theme, I recently changed my background so I have at least two that I know work for me (plus another one that I know does NOT work ).

tobyed: No rules on that (we try to avoid additional rules and get along with as few as possible). So go ahead...

I had a little play with your picture, this was a quick shot. What I did was the following:
Duplicated the pic in a new layer and applied S curve so that the distant part got more definition (which means that the foreground does look horrible, much too much contrast ).
Added layer mask and applied gradient tool (black to white) to that layer mask. Then I took a soft (black) brush and painted over the dark bushes (to weaken the effect of the S-curve on them).

As that did weaken the effect too much I copied this second layer, both are 100% opacity (therefore it is perhaps a little overdone for illustrative purposes ), one of them I changed to layer mode soft light.

With a bit more care on the mask (and using the original picture) I think more could be achieved, though for a quick fix it ain't too bad, or?

[IMG]http://i156.photobucket.com/albums/t5/Prieni/Mhuni_test.jpg[/IMG]

The oversharpening, of course, is a bit stronger now, but one would do all this prior to sharpening anyway.

Hope this helps,
Prieni

Sigma 105/2.8 DG EX Macro
[IMG]http://i156.photobucket.com/albums/t5/Prieni/9390413.jpg[/IMG]

FA J 18-35mm F4-5.6 AL (*istD kit lens)
[IMG]http://i156.photobucket.com/albums/t5/Prieni/IMGP0912dr.jpg[/IMG]

Thanks for your kind words. I think that the Rialto bridge (2) and the Tower bridge are more "documentary" shots. The light on the Tower bridge was pretty good but of course I have seen much better shots of it.

Cheers,
Prieni