Fast standard zoom lens for APS-C DSLR cameras with a constant f/2.8 aperture.
The Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical IF is the first-generation constant-aperture standard zoom for APS-C Canon DSLRs. Di II = APS-C image circle; XR = Extra Refractive; LD = Low Dispersion; IF = Internal Focus. The constant f/2.8 aperture across the 17-50mm range is the key feature for event and portrait photography.
17–50mm zoom range (25.5–75mm equivalent on APS-C), f/2.8 constant maximum aperture, Di II (APS-C), XR/LD/IF formula, Canon EF-S compatible mount.
The first-generation Tamron 17-50mm f/2.8 Di II delivers constant f/2.8 brightness across the standard zoom range for APS-C Canon photographers at an affordable price. The IF mechanism keeps the front element stationary during focus. Competes with the Canon EF-S 17-55mm f/2.8 IS USM at lower cost (without IS).
Inspect for fungus, haze, and coating condition. Test AF accuracy. Confirm IF mechanism. Confirm Canon EF-S mount engagement. Check aperture blades.