Originally posted by reeftool A few comments mentioned a good time to change systems. Have any of you looked at Canikon lens prices? You won't save any money there and will likely spend much, much more. They have their "consumer" lines which are average lenses at best. Their good glass is incredibly high.
Yes, Nikon lens prices are quite high. The 24-70 f/2.8 is $1700 or so, so maybe 10% more than the 16-50. Of course the image quality with a D800 will blow the pentax away and there's a DOF penalty with the pentax as well. It's a pro lens, rather than just having pro pricing.
If you go with constant DOF, the 24-120 is half the price of the 16-50, has longer range, and with the D800's iso I suspect it will have less noise in low light. I also suspect it focuses better than the pentax and I don't think people worry about the lens motor failing.
The 70-200 is ~10% more than the Pentax 60-250. It's a faster lens, suspect it autofocuses much better, and again, has better IQ due to larger sensor.
Really the 10% isn't going to make or break me. I didn't come to Pentax for the autofocus, I came in spite of it; it wasn't that important to me, but it'd be nice. The major difference is the bodies.* Is the $1500 more for the FF Nikon (at introduction) worth it for me for the improved IQ and actual pro-quality? It wasn't when the lenses were so much cheaper, but now that my resale value for the lenses has just made them a great investment, it might be. Availability of third party lenses just makes this scenario sweeter.
*The limited lens series is also a big difference for me, but if I can get better IQ carrying one lens than carrying 3, the advantage diminishes.