Originally posted by Queued Is it really a fools folly to jump ship and move her to Pentax?
Most certainly.
If she likes what she has, then keep your wife happy. After 30 years of marriage I've learned that one at least.
For a more technical response. . .I'm sure some folks may provide you with seemingly strong Internet-based opinions; I'll speak from direct experience.
The Canon 70D is a really good camera. The K-3 seems like a really good camera too, but I cannot see how a change will benefit her significantly. I've owned a 7D for the past four years; I think the sensor is pretty similar to the 70D as are many components (excepting the nice articulated LCD of the 70D, and the higher performance of the 7D). I've owned the K-3 for over two days now. I'm undecided whether to keep the K-3, even though I've got a sizable stash of excellent K-mount lenses from past years of DSLR use.
While the Canon sensor is older and a little noisier, for 98% of most shooters' needs it serves them quite well. Good post-processing skill helps. I don't think most civilians will see any differences in prints made that are under 18-inches in size. Canon's AF is still top notch, I'll compare it to the K-3 after a soccer match shoot tomorrow. I've sold plenty of shots taken with a 7D and have several bird and landscape shots published in another author's book that comes off the printer next week. Canon has significantly improved the usability and interface since your 5DMK2 (which I use frequently) to where I prefer some aspects to the K-3. I think certain button placements on the K-3 are less-than-wonderful, and the camera is not all that small or light---especially with longer glass, unlike earlier Pentax models. Pentax flash system is inferior to Canon. Period.
Finally, the two zooms your wife has are notably better than anything in K-mount right now. The 70-200mm f2.8 is considered one of the greatest zooms available, if not the best, so why mess with that?
All DSLRs are amazingly good these days, and if one is vested with a platform that serves their needs quite well, then the rationale for switching is weak IMHO.
M