looking for a lens
price isn't important but what I'm after is something that
zooms wider than 28mm (mostly looking for 18-24mm)
excellent optically
reasonable chance of getting a good one and still be good in 12 months
isnt chock full of ca / fringing (I can get rid of it, but it still leaves marks (short of putting a huge amount of work))
is available new (I'm long done with ebay & 2nd hand glass)
so I have ruled out pentax 16-50 / 16-45 / tamron 17-50 / sigma 18-50, is there anything else??? is high ca just the nature of beast when wider than 28mm??
Phil