Compare lenses

Pentax HD D FA 24-70mm f/2.8 ED SDM WR vs Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF)

The Pentax HD D FA 24-70mm f/2.8 ED SDM WR and the Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF) side by side, computed from this guide's catalogue.

Which to pick

Pick the Pentax HD D FA 24-70mm f/2.8 ED SDM WR if you want coverage of full frame, so it suits the larger-sensor bodies too. Pick the Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF) if you want a design for APS-C, which usually means smaller and lighter and a fit on more cameras (59 against 20 in this guide).

Still torn? Ask the guide about the Pentax HD D FA 24-70mm f/2.8 ED SDM WR and the Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF)

Specs side by side

Rows that differ are in full colour; the better value is marked where one is better by any measure.
Spec	Pentax HD D FA 24-70mm f/2.8 ED SDM WR	Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF)
Maker	Pentax	Tamron
Focal length	24-70mm (zoom)	17-50mm (zoom)
Full-frame equivalent	24-70mm	26-75mm on APS-C
Maximum aperture	f/2.8	f/2.8
Made for	Full frame	APS-C
Mounts	Pentax K	Canon EF, Nikon F, Pentax K
Stabilised	no	no
Autofocus	yes	yes
Zoom range	2.9×	2.9×
Weight	787 g	not listed
Cameras it fits	20 in this guide	59 in this guidefits more cameras

Focal range, in full-frame terms

Pentax HD D FA 24-70mm f/2.8 ED SDM WR: 24-70mm.

Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF): 17-50mm on APS-C, like 26-75mm.

Aperture

Pentax HD D FA 24-70mm f/2.8 ED SDM WR: f/2.8 wide open.

Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF): f/2.8 wide open.

Each opening drawn to scale against f/1.4: a smaller f-number lets in more light and blurs the background more.

Field of view

How wide each sees, at each end, on the sensor it was made for.

Cameras they fit

20 cameras in this guide take both, so either works on the same body. In all, the Pentax HD D FA 24-70mm f/2.8 ED SDM WR fits 20 and the Tamron SP AF 17-50mm f/2.8 XR Di II LD Aspherical (IF) 59.