CA is a bI take 95% of my shots with water in them, living on an island it is what I shoot a lot of. I am concerned at the comment you have made about CA and water, can you, or anyone be more specific ?
I looked at the 16 - 45 group on flickr and all I see is superb sharp shots,many inc water but do not see CA.

Many thanks for that on the 16-45, I think I will go for it along with the 55 - 300.

For better or worse I always look at photozone before buying a lens and in particular the mtf figures. The 16 -45 has a very healthy set of mtf figures and is on course to do really well in the review but then CA is brought up and it seems to mar the performance of the lens. Could users indicate if it is an issue or not,and if so where is it likely to appear.
I am looking to buy this along with the 55-300,cost new is £400 but it is expensive when compared to the 18 -55 Mk11 and the 55-300 for £250, is it worth it ?
Then there is the 18 -250 option, Pentax or Tamron which whilst 50mm less at the long end, is so versatile and keeps the dreaded dust to a minimum, any thoughts advice, sorry if this has in part, or all, been discussed previously.

Open to offers before it goes on ebay.

Clicked on you flickr link but it only shows two images in the photostream,( both very nice) is there more ?. If you are watching it on ebay then here is a link to flickr with a lot taken by the Sigma.
http://www.flickr.com/photos/donaldm/

Can we please stop,forgive, and forget. If I was wrong in responding the way I did to a £200 offer then I am sorry. What I would hate is for this forum to descend into the sort of mince that goes on elsewhere like the forums on dpreview.

Anyone want to trade a Pentax 18 - 250 for a Sigma 10 - 20mm ?

If you had clicked on the ebay link you would have seen that it has a starting price of £250, that along with a bit of research beforehand by simply googling the lens would have revealed that it currently sells for over £350 without filters.
If as a forum memeber you are offended then I apologise, but perhaps you could ask yourself if when making an offer is my starting price even realistic and maybe alter the tone of offer from "is £200 any good to you" to language that might not trigger an attitude that you find "nice".

Ebay and paypal have become very expensive, thats why we should be doing far more on here. If a forum member sells to a forum member on ebay then its nuts, far better to sell for less on here with no fees than to fund ebay with their crazy 10% fees. As long as the offers are sensible .

£200 for a lens currently costing £389 at SRS, with £40 of filters, are you having a laugh ??

Anyone interested in doing a swop, looking for a Pentax 18 -250. Lens currently on ebay.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170322627871