A pro-level version of the 28–135mm, it has weather- sealing and a constant aperture, but not pro-caliber test results in distortion and vignetting.
Standout Spec: Construction. It's a last-forever lens.
Lens Test: Canon 24-105mm f/4L IS USM AF
Pentax 12–24mm f/4 Pentax DA*ED
Nikon AF-S DX Zoom-Nikkor 10–24mm f/3.5–4.5G ED
SIGMA 24–70mm f/2.8 EX DG HSM
Sigma 12–24mm f/4.5–5.6 EX DG HSM
Tamron SP 10-24mm f/3.5-4.5 DI II LD