Compare lenses

Pentax smc DA 17-70mm f/4 AL [IF] SDM vs Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary

The Pentax smc DA 17-70mm f/4 AL [IF] SDM and the Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary side by side, computed from this guide's catalogue.

Which to pick

Pick the Pentax smc DA 17-70mm f/4 AL [IF] SDM if you want the flexibility of a zoom. Pick the Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary if you want a brighter f/2.8 (1.0 stops more light), for dim light and softer backgrounds; optical stabilisation, which helps most on bodies without it; and a fit on more cameras (51 against 20 in this guide).

Still torn? Ask the guide about the Pentax smc DA 17-70mm f/4 AL [IF] SDM and the Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary

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 smc DA 17-70mm f/4 AL [IF] SDM	Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary
Maker	Pentax	Sigma
Focal length	17-70mm (zoom)	17-70mm (macro)
Full-frame equivalent	26-105mm on APS-C	26-105mm on APS-C
Maximum aperture	f/4	f/2.8-4brighter
Made for	APS-C	APS-C
Mounts	Pentax K	Canon EF, Nikon F, Pentax K
Stabilised	no	yesstabilised
Autofocus	yes	yes
Zoom range	4.1×	4.1×
Cameras it fits	20 in this guide	51 in this guidefits more cameras

Focal range, in full-frame terms

Pentax smc DA 17-70mm f/4 AL [IF] SDM: 17-70mm on APS-C, like 26-105mm.

Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary: 17-70mm on APS-C, like 26-105mm.

Aperture

Pentax smc DA 17-70mm f/4 AL [IF] SDM: f/4 wide open.

Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary: 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 smc DA 17-70mm f/4 AL [IF] SDM fits 20 and the Sigma 17-70mm f/2.8-4 DC Macro OS HSM Contemporary 51.