I am looking to equip myself with a wide angle zoom to compliment the 18-70 and 18-200 that I already have. There are three sizes widely available:- 10-20mm by Sigma 12-24mm by Tokina and Nikon 10-24mm by Tamron My 18-200 is Tamron which tends to be a bit soft unless well stopped down, but I have always liked the brand. However reviews that I have read suggest that the 10-24 tends to be softer than most. I too like Tokina: I have a 24-70 on one of my film cameras and have always found it to be a good optic. They do have a tendency to be a bit pricey though. I cannot afford the Nikon. I have a Sigma 28-200 for film and have never found it to be particularly good, so I am a little sceptical about the 10-20. My problem: will I see much difference at the wide end between 10mm and 12mm? Distortion tends to be most prevalent at the ends and it bothers me that if I go for the 10-20 I will have distortion at the long end of that lens and on the wide end of my 18-70 Nikon. It worries me that I may have a small band of focal length that I cannot use - in that respect the 24 would at least give me some possibilities. Sod's Law says that the 18-20 band is just where I might need to be sometime! Has anyone on here used any of these lenses and thus experience of them and can give me advice? I want the lens for the occasional panorama and for architecture, particularly ecclesiastical. I mainly use a Nikon D80 but also have a D70s which I tend to use as a standby with longer lenses. TIA