Canon EF 24-105mm f/4 L IS USM on Rebel XSI

[neuroanatomist]

In the center, at least, Bryan's ISO 12233 chart images show that the lens is very sharp at f/4, at all focal lengths. Ideally, zoom lenses should be tested at their longest focal length, and at 25x that focal length (your 8 foot test fits that criterion). You may have a lens in need of service - if it's new and under warranty, definitely call Canon. If you bought it used, it's still worth a call to Canon Service - they'll give you a free estimate if it needs repair. Honestly, the 24-105mm f/4 is a much better lens than the 15-85mm f/3.5-5.6 - I really think you're better off with the 24-105mm lens, unless you really need the 15-24mm range (in which case, I'd suggest the EF-S 10-22mm).


Personally, I do have a couple of EF-S lenses, but they're lenses for which there's no real L-series equivalent, i.e the 10-22mm f/3.5-4.5 andthe 17-55mm f/2.8 (the latter was a tough debate vs. the 24-70mm f/2.8L, but i wanted the IS and the wider end for my 'walkaround' lens).

[DavidEccleston]

Ok, so I once again put my stove's hood's light to work, along with a nice black and white logo on a box (PC Organics Oreo ripoffs cookies, before you ask), the cookie's ingredients list, and the text near the tab on a box of some Premium Plus crackers.


From this I can see, when at 105mm, from 3', that the white of the box is ghosting 3-5 pixels into the black text on the cookie's logo. Aside from this one case with a large contrast with stove lamp glaring off the white of the box, everything else seems fine.


*shrug* Not sure what the issue was on the other shots I took. Perhaps glare again, though from the sun. Anyway, I can safely say I've now put this lens though it's focus-based paces, and aside from the focus being on towards the near edge in the one ruler test, everything seems fine.