Originally posted by ivanvernon
Another great lens is the FA 24-90, f 3.5-4.5, which for me is actually is the best of these three lens for most anything except low-light situations. You lose a little on the wide-angle end, but gain a lot on the high end. In my experience the 24-90 is one of the most under-rated Pentax lenses. In my experience, this lens is a little like carrying around a bag of primes (except in the 31, 43, and 77 mm focal lengths, where there are better choices :>). It would be a great kit lens and excels in many ways, not necessarily including build quality.
Spot-on. The FA24-90 is a very good lens indeed (well, my copy is anyway), and the range is ideal for general walkaround purposes with an APS-C sensor. Stopped down a bit, it is close to 'prime' quality. Reviewers have correctly referred to its slightly 'loose'-seeming build, but that doesn't seem to affect its optical performance. It is better than the 18-55, which is not stellar, in my experience, but even the 18-55 is not bad, and can be very useful when lightness and compactness matter.
After buying the FA24-90 secondhand, I bought new the original version of the Sigma 17-70. The third copy (the first two were duds, as the distributor admitted) of the Sigma was/is very good, but I find it unpleasantly heavy. I have reverted to using the 24-90, which remains as rewarding as ever, and teams well with the DA15.