Your best bet is probably the DA 18-55, as it is really inexpensive and
gives a 35mm equivalent FL of 27mm.
I have used the inexpensive Sigma 24-70 f3.5-5.6 HF zoom (ca. $130) for
this situation and it works just fine. Its quality is a lot higher
than the price would lead you to expect, its light, and it doesn't
vignette the onboard flash. The only drawback is that it only delivers
a 35mm FL equivalent of 36mm.
Another possibility is the Pentax FA 20-35mm F3.5-4.5 zoom, but it
costs a lot more. No vignetting, and it delivers a 30mm equivalent FL.
Regards, Jim
