You did not mention your price range, so I'd recommend these two expensive and excellent lenses: Canon EF-S 17-55mm f/2.8 IS USM Lens Canon EF-S 15-85mm f/3.5-5.6 IS USM Lens
I can't speak for the Tamron because I've never used it. I own the Canon EF-S 17-55mm f/2.8 (purchased used for $800) and it's the one I currently use for landscape and architecture. It has great image quality.
I also own the Canon EF 35mm f/2, non IS version. It's a great little lens, but maybe not wide enough for some architecture shots.
Comments
Canon EF-S 17-55mm f/2.8 IS USM Lens
Canon EF-S 15-85mm f/3.5-5.6 IS USM Lens
I have a Tamron 17-50mm f/2.8 Non-VC lens. Would that be a good one as a replacement for the Canon Ef-S 17-55mm f/2.8?
Also what are your thoughts on the Canon EF 35mm f/2 IS and Non-IS?
Thank you,
Phanindra G.V.
I also own the Canon EF 35mm f/2, non IS version. It's a great little lens, but maybe not wide enough for some architecture shots.