[Wheatfield]

Nikon has been all over the place with lens compatibility, so the concept of being able to use a 25 year old lens on a new camera is probably an unheard of concept.

This actually isn't the case. Unlike Canon, Nikon didn't change their mount when they started putting AF motors in their cameras, so you can still use almost any F-mount lens on the newest Nikon bodies. There are some *really* old AI lenses that won't even meter on new bodies, but nearly all of their old lenses are still shootable.

This actually is the case, though they recently seemed to have gone to some effort to improve the situation.
Look at any lens/body compatibility chart and you will find inexplicable feature loss (loss of metering being a biggie), and lens series that won't mount at all, so it pays to check to make sure what you are buying will work with what you have if you are going outside of equipment that is contemporaneous with each other.
Canon wholesale changed their lens mount, and it's pretty well accepted that they buggered their user base in the process. As an aside, Canon does not put AF motors into their bodies, and never has.
Pentax has maintained backwards compatibility with lenses made right back to the early 60s.

[Marc Sabatella]

I think overall, most DSLR's are similar enough when it comes to basic concepts and operation, the fact that you know Nikon and she has Pentax won't be a huge issue. Knowing lenses will be, and as you have more specific questions on additional lenses, by all means, ask them here, but the 18-55 + 55-300 is a great basic kit and could be all she ever needs.

So, racking my brain to think of specific things she might ask that you might not be able to help already:

- SR is turned on by a switch on the back of most models (or via a button press or two on the latest models) and can be left on at all times, but ideally should be turned off if she uses a tripod. In which case, she may also want to use the 2-second timer for mirror lockup, and this turns off SR automatically. That is usually accessed by the Fn button on most if not all models.

- The SR mechanism means the sensor floats freely most of the time, so if she hears a "clunk" when she shakes or rotates her camera, tell her not to worry.

- If she wants to use any manual lenses, check out the sticky thread in the beginner's forum on the process. That forum would be a good place for most other basic questions you might have, too, and in fact, this question could just as well go there. But because it's kind of a unique series of questions, I'm not really inclined to move it. Another mdoerator might decide otherwise.

- She will probably like P mode with the "hyperprogram" feature that allows for fully automatic shooting but also lets the dials on the camera to quickly shift you to Av or Tv modes so she can override the aperture or shutter speed quickly and have the camera adjust the other parameters to compensate.

- Pentax provides two RAW formats, PEF and DNG. if she shoots RAW (which I doubt she will), then she'll inevitably ask which to pick. Answer: it doesn't matter unless the software she uses happens to support one but not the other. A lot of programs won't support PEF from brand new models, but will add support eventually; DNG is usually supported right off the bat. but some programs don't support DNG at all, from any camera.

[deadwolfbones]

While you're right that lens compatibility for Nikon isn't as strong as for Pentax, I have to say I've been really pleased with the implementation Nikon opted for, in terms of using AI and AI-s lenses on my D700. Focus confirmation is accurate and easy and the metering is perfect. Could be a lot worse.

[Entropy]

Given the glass she has, definately consider new glass, especially since she wants to do closeup photography.

One thing I mentioned before, but:
Most would reccommend the Pentax 55-300 over the Tamron 70-300 these days, but you might want to check the minimum focusing distance of each - the Pentax may have a much longer one. The Tamron 70-300 is a dirt-cheap lens that performs amazingly well for its price. The 55-300 is better in most situations but is over double the price.

[Peter Zack]

I'll chime in as a newish owner of a K-x and also owning the *istD, K10 and K20. She will see a big difference from the *istD. The LCD is so much better, the speed (operation, processing etc) is 5x what the *istD was (but we are talking about a 7 year old design).

Easier menus and a host of other features that she will enjoy over the older camera. I think the kit you linked is perfect for her and the budget.

I wouldn't rush out to buy a tripod. With good shooting technique, you can get 3-4 stops out of the in body SR. I tougher light situations or long tele shots, she's going to see a huge difference in the number of "keepers".

With the *istD, you may want to consider selling it here and I see you already have an offer above.