Pentax smc da 17 70mm f 4 al if sdm vs pentax 18 50mm f 4 5 6?

I don't have a page on cst1 likes cameras for the Pentax smc DA 18-50mm f/4-5.6, so I can't compare it fairly against the 17-70mm, and I won't guess at its specs.

The [Pentax smc DA 17-70mm f/4 AL [IF] SDM](/gear/lenses/pentax-smc-da-17-70mm-f-4-al-if-sdm/) is an APS-C zoom with a constant f/4 across its range. It isn't stabilised, and it fits Pentax K bodies such as the Pentax K-5 and the Pentax KP. On APS-C it frames roughly like 26-105mm on full frame, which makes it a sensible all-round standard zoom.

If you want a brighter zoom, the [Pentax smc DA* 16-50mm f/2.8 ED AL [IF] SDM](/gear/lenses/pentax-smc-da-16-50mm-f-2-8-ed-al-if-sdm/) is the older f/2.8 version. It has since been replaced by a newer PLM model. For how aperture affects exposure and blur, see the lenses guide.

Written by Claude from this site's pages.