Hi Phil
Re your post:
Quote: I think this lens is my new 'if I had to take only one lens on a trip..... ' lens.
.....thus encapsulating
precisely the reason that I finally chose this particular 'all-purpose' Tamron lens ! I'm fully prepared for the inevitable
battering I'll probably receive from the 'prime-lens' brigade, but I've developed a pretty thick skin over the years and ultimately whatever DSLR body/lens combination I select & how I choose to use it remain
my decision. I believe that those two untouched (but reduced) originals clearly illustrate that the 18mm - 250mm Di II is certainly no 'slouch' when it comes to producing great image quality and I don't feel I have anything to apologise for on that score !.......I'm actually exceptionally envious to discover that you've got a Sigma EX 10-20mm hiding away in your 'goody-bag'. I tried one out briefly at the time I purchased my K10D and it's truly an
astonishing lens to behold through the viewfinder, with very little visible distortion that I could detect. Without a shadow-of-a-doubt the Sigma 10-20mm will categorically be next on my hit-list and then I'll have most 'bases-covered', apart from the extreme telephoto department, which is honestly rather out of my sphere of interest ! Oh, not forgetting a second body of some description.....K100D ??.....K100D 'Super', or should that be pronounced 'Soooooparh' !!! What a 'stuuuuupid' model description !
and in reply to Richard Day:
Quote: At what focal lengths does it change f stop?
I'm afraid I simply don't have this information at my disposal and only wish that I was in a better position to assist you in this regard. Might I perhaps suggest that you contact the importers of Tamron lenses in the U.K. (Intro 2020 - see link below) who should hopefully be able to advise you ?
http://www.tamron.co.uk/
Best regards
Richard