looking for my first prime!!

If DA40 is out of price bracket, have a look at F50/1.7. They usually go for around £100 and are stunning lenses. AF as fast as DA40, great contrast, colour rendition, sharpness etc....
now 50 maybe too long, but for kids I think it would be great....

I might have to have a rethink then! The DA 21mm Ltd is a fair bit more expensive but I may just have to save for a bit longer...

If you are getting just one lens, also consider the DA35. It will get the shot when kids come rushing up to you, where other lenses will miss due to their close focus limits. And it's great also for macros or landscapes; it's pretty much a do anything lens.

I use the FA43 but miss shots when my "kids" (that is, pets) come too close and I have to back off. But otherwise I manage shots like this:

[IMG]http://farm5.static.flickr.com/4016/4495485324_c1c632f483.jpg[/IMG]

Dave,

You've already got some good advice here. I wonder though what you actually intend to do, when you say 'predominantly indoor pics of the kids'?

Two parts to that - what hangs off the word 'predominantly'? What else will you be doing with it, and how does that affect your choice/s?

Secondly, pics of the kids: Are you looking at action shots of a number of kids? (I reckon you probably are). But - perhaps you are doing portraits of individual kids? These two choices of 'kids pics' are important for you. If it is about groups of kids in action, flexibility and a wide angle are more important. That may suggest a closer look at a short zoom.

If it is mainly kids portraits, then a portrait-length prime (eg a fast 50 or 70mm) might be better for you.

But the 'other' uses you are contemplating may have a bearing on your choice too. Perhaps a zoom to start with, and then do a check of all your images after a time to see what focal lengths you're actually using?

The you could make some further evidence-based choices on additional lenses (or not )

As Stefan, I think, said, you can't really go wrong with any Pentax prime, so what you choose has to be on the basis of focal length and affordability.

On a DSLR, anything over 40mm falls into the portrait category. Good for faces, but not so good for groups, and hard to use on fast-moving kids. The 50mm lenses are all wonderful, however, and if you choose a manual one they will be cheap (relatively). The 55mm is a beaut, but not cheap.

35mm equates to the traditional "standard" lens, and all the Pentax 35mm lenses (old and new) are lovely.

31mm and under is wide-angle. If you can afford it, the 31mm will be the best lens you'll (probably) ever own. If not, the Sigma 30mm is well regarded by Sigmaphiles, and the Pentax 21mm Ltd is significantly wider and not too bad optically.

If you just want portraits, and tight ones, the 77mm is a marvel, and the 70mm not bad at all.

G

Perhaps you could try the outdated theory of saving a stack of coin, and buying "old" but still fantastic Pentax glass for a fraction of the price of the new stuff. I've bought an A 50 f1.7 manual focus and a Takumar 135mm f2.5 lens on ebay for about 80 of your quids all up. Those old lenses are built like a tank, and quite often, can compete rather favourably against the modern plasticky lenses. (having said that, I'd swap those two for a 50-135 f2.8 in a heartbeat. Any takers?).
Regards

would you?

I had DA*50-135 and went exactly the other way... Sold it and kept 50/1.7 (F series) and got myself FA135/2.8. Both of them better than the DA* in just about every respect.
But... I sold them both to fund my 43 and 55/1.8... found 135 tad too long anyway. I'm keeping my eye out for 77/85. Maybe 100 we'll see

I went from DA40 + DFA100 to a DA*50-135 because of the versatility that wanted but I could afford the change without selling the primes so still use them all but for portrait the DA*50-135 is just perfect.

I also still want a nice series of Limited lenses, I still have my hopes up for something like a DA135 f/2.4 limited or f/2.8 if it's very small.

I don't know.
50-135 was a great lens, but never charmed me enough. Don't know what was it... maybe my K10D's f*?!ed up AF (I keep it in permanent debug mode now so each lens is spot on).
It was sweet lens, and I agree that it was great portrait range, but I never appreciated it more than my primes.
One thing though, it's not really 50 when focused to ~1.5m. Quite a bit wider actually...

still, it's one of those lenses that call my name saying: get me again!

BR
Peter