[normhead]

Have you also considered the 55-300 PLM? Slower, but a very well regarded lens, also much more compact and versatile. Landscapes typically don't call for fast lenses.

Slower aperture, but faster focusing speed. It will leave any older SDM lens in the dust.

On a K-70, the DA 16-85 and DA 55-300 PLM are pretty much an unbeatable combination. You can then analyze your images and decide where it would be most useful to fill in with primes.

In my case the DA*55 1.4 for low light
The DFA 100 macro for macros.
An HD Da 1.4 TC, more magnification for macros, more reach fo telephotos.

I'd add the 11-18 for UWA but I already have the excellent Sigma 8-16.

All are lightweight and WR for easy carrying and nimble usage in all weather conditions.

[mikesbike]

The DA 55-300mm PLM lens would be a good matchup with your existing lens, which is a pretty good kit lens. And this 2-lens kit will be unusually compact and lightweight, as well as giving you a huge zoom range, with WR construction all the way. This is your most versatile and cost-effective combo. Just go to the SLR lens section of the forum, go down to check out the thread: "HD Pentax DA 55-300mm f/4.5-6.3 ED PLM WR RE- Show us what it can do, what it CAN'T" Start with the last page first (most recent) and work backwards, and see what you think. You will find many sample photos.

The DA* 50-135mm f/2.8 is in the upper class of zoom lenses, optically and in its usage. Its f/2.8 aperture capability can provide 4 times the shutter speed at 50mm compared to your DA 18-50mm zoom lens, as could the DA* 16-50mm f/2.8 PLM. The longer DFA 70-210mm f/4 is also in an upscale lens category. But these are costly lenses. If you customarily shoot hand-held in good lighting, or use a tripod, you might seldom need this aperture capability, and the K-70 has exceptionally effective low-noise capabilities when needing to raise ISO settings to address low light conditions, and can thus compensate to an extent for the less aperture-capable lenses.