Pentax 24 70mm f 2 8 vs pentax 28 105mm f 3 5 5 6?

I don't have a page for the Pentax 24-70mm f/2.8 yet, so I can't compare the two properly. I can tell you about the Pentax HD D FA 28-105mm f/3.5-5.6 ED DC WR. It's a compact, weather-sealed full-frame kit zoom. On full frame it frames 28-105mm as marked, and on APS-C it behaves like 42-158mm.

The aperture is the main difference to weigh. A constant f/2.8 keeps the same exposure across the whole zoom range and lets in more light, which helps indoors and at dusk. The 28-105mm gets darker as you zoom in, but it's lighter and cheaper for everyday shooting. The aperture section explains the trade-off in more detail.

If you mostly shoot landscapes, a standard zoom like 24-70mm covers most scenes, and f/4 versions are lighter than f/2.8 ones. See the landscape guide for more.

Written by Claude from this site's pages.