Lens dilemma

[michellemandat]

My "old" 18-55 has something like sand in the AF mecanism. I suppose that gear is slightly broken. But I can focus

with it.

I plan to change it for the same lens or a better and in this case what is the best choice, Tamron 17-50 or Sigma 18-

50 or 18-55 II?

My camera is IST ds.

Thanks.

Michel

http://m.lemandat.free.fr/coppermine/

[ianmaleny]

Pentax 16-50?

[musings]

Agree with Ian...my vote would be Pentax DA*16-50mm/f2.8. It's a sealed lens so perhaps the sand problem on your kit lens won't be an issue here. Sure helps when it's raining or really damp outside, too.

[andrewg_ny]

Consider which kit lens shortcomings you want to address. If you want improved wide angle, the DA16-45 wouldn't be a bad choice. If you want more reach, then Sigma or Pentax 17-70 might be considered. It sounds like you are considering constant f/2.8 zooms as well--I don't know how these can be directly compared to the 18-55 as they are in an entirely different cost (and size/weight) league. If you do most of your shooting stopped down or with flash, then the kit lens will do very well. All the 'upgrade' lenses include some degree of improvement in the performance envelope.

[duane_mills]

There's also a Sigma 17-70mm F2.8 that's worth looking at. Nice range and fairly fast for low light.

[pavelt]

I upgraded from the original 18-55 to a 16-45/4, and it's been my most used lens since. It's was a bit large on my K100D but not too front heavy to be unbalanced. It balances great on my K10D with grip. It goes quite wide, is fairly sharp from f/4, and it focuses quite close for a non-macro lens. At current prices it's a steal!

 

The Tamron 17-50/2.8 looks like a very decent alternative to the Pentax 16-50/2.8, if you need f/2.8 speed.