I’m officially tied of my 18-55mm. After taking hundreds of photos and several side by side tests of tree branches, I’ve concluded that between the low sharpness, low color separation and CA, I just cannot get a image that is crispy and clean enough for me. Especially when you compare the images to those from the 70-200, they are just pathetic. Granted, it was used. I paid $100 for it so I don’t feel too bad to keep it or sell it. Next question is tougher, what do I upgrade it to?

(http://camerablognetwork.com/2009/05/canon-17-40-versus-18-55-is-comaprison-revisted-post-canon-50d-af-micro-adjust/)

Options:
EF-S 15-85mm f/3.5-5.6 IS USM $799.99

EF-S 17-55 f/2.8 IS USM 17-55mm f/2.8 IS USM $1,179.00

EF-S 17-85mm f4-5.6 IS USM 17-85mm f/4-5.6 IS USM $599.99

EF 17-40mm f/4L USM $839.99

EF-S 10-22mm f/3.5-4.5 USM $859.99

(The prices are Canon’s official prices. for reference.)

Both 17-55 f/2.8 and 10-22 get very high recommedation. 17-55 is a great walk around lens and 10-22 is highly recommended and used by pros for landscape. But since 17-55 is twice the price and still a EF-S, I’m excluding that one (very hard since people keep bringing that up!) 10-22 is nice but a bit too specialized for me at this point. So it’s a pass too.

There are 3rd party lens that are highly recommended, but I still feel a little intimidated to go that route (Tamron 17-50 F2.8, Sigma 17-70)

Ok. between 15-85, 17-85, and 17-40 f/4L. 15-85 is newer and positioned to replace 17-85 and supposedly has better IQ. Though the latter is a bit cheaper, especially if you get a used one, I decided to skip it this time.

Between 15-85 and 17-40…ahhh, it’s a really tough call. The first one has bigger range (I do like the additional 45mm. Even on the 18-55, I notice myself wanting to go longest often, but then I’m bugged by the 5.6 aperture.) The IS is really really attractive too. Most reviews are saying the IQ of 17-40 is just slightly better than 15-85.

I finally found a good thorough review of both lenses (though I wished he had a tree branch comparison. To me, that’s often the nail on the coffin.
http://www.parkcamper.com/17-40-versus-15-85IS/Canon-15-85-versus-17-40L-comparison.htm

(“The 15-85 IS USM is a great lens, obviously it has the most range of all before mentioned lenses, it’s very sharp, has less distortion and CA than the 17-85 and has very effective IS. Obviously it’s the most expensive too – it goes for ~$700 – at this price you can consider the 17-55 F2.8 IS too.”)