The info on this lens has been leaked:
http://www.pentaxforums.com/forums/205348-post47.html

Nice food too.

I notice a couple other new lenses on the roadmap have SDM, like the 50mm replacement. Not sure if it's a good thing that these drop the screw drive. backwards compatibility is one of the things Pentax has been known for.

The original kit lens is f/3.5 only at the very wide end. As soon as you narrow a bit it jumps to being the same as the 16-45mm, which then beats it slightly the rest of the way. But you are right in saying this is "hardly any faster". Basically they capture the same light with one having the advantage of fixed aperture.

Both have similar distortion but the 16-45mm has significantly less vignetting at 16mm than the kit has at 18mm. At the wide end it also has better resolution figures at the border even though you get 2mm more.

Certainly the difference may not be earth-shattering, but it is distinct for those needing the extra field of view. It was enough for me to purchase it as a drop-in replacement for the kit.

Is the Mark II really that much better than the original? I'd be interested to read more about that.

This will have the advantage of SDM. If the IQ is good it will make a very crowded product range. I find it hard to understand why there even is a 18-55mm Mark II when the upcoming zoom looks like a better kit option.

Fair enough, but I have a difficult time ignoring the more enlightened folk at Photozone and Pentax Forums as well.

Am glad you got a good copy of the lens, but quality control on this one was truly a scandal relative to Pentax's usual standard.

Also best to have redundancy in photographers!

One reason I don't do pro gigs: only one body at present. Need to wait until the K20D comes down in price. Must wait...

Must wait...

Must wait...

I know what you are saying here about the Internet effect. But far more than "one or two" people have had this problem. One of the most trusted reviewers on the net refused to even look at the DA* because the samples were so bad. If you live near a dealer and can afford the time to return lenses until you get a good one (people have done this multiple times, surely a sign there are more than one or two bad copies) then fine. But this turned me off the lens completely.

If you do get a good copy that's fantastic, but you will still need something faster than f/2.8 for indoor shots, particularly things like signing the register. I prefer another stop faster again, if only so the viewfinder is clearer.

Back to the original poster: I think you should look at this site:
http://planetneil.com/tangents/flash-photography-techniques/

There's lots of amazing photos and good techniques using indirect flash mainly to fill in with ambient light. Even if you cannot use flash in the church, there is a page on available light that illustrates some possibilities. The photos there were taken at f/1.4, f/4, f/5, f/2.8, f/1.4 and f/2.8 respectively.

Splitting the difference on the f/2.8 shots, I learn from this that half of the available light shots could have been done with the 16-45mm. On a second body swap between your 50mm f/1.4 and 70mm f/2.8.

At current prices this will cost you only £50 more than the DA* lens alone.

A fast 35 / 50 / 70 makes a good group of lenses, with your zoom for the telephoto end. I have never done a wedding but have been a semi-involuntary guest at several. And what I remember is that there is an awful lot of waiting around. Tons of time in which to swap one fast lens for another. It's not like a horse race or something.

I would echo the previous replies and say the 16-45mm f/4 is a good choice at one stop slower than a 2.8. This would work for cutting the cake, getting group shots at the reception, etc. Any time you need something wide and sharp to the edges, with good colour rendition but still flexible in FOV. Maybe you'd be surprised how often 16mm comes in very handy, to capture an entire party around a table for example. 35mm is not going to do that. I imagine you could use a diffused flash in these instances so the speed will not be an issue.

For the church ceremony perhaps a tripod is your friend? You need to scope out the terrain ahead of time, ask permission etc. If you get no special privileges I'd be surprised... the bride usually has a lot of pull in situations that involve her image being fixed for all time in a photo album! If you cannot use a tripod or flash sneak a monopod, or brace against a pew... you should be able to arrange a good spot.

If you absolutely needed a faster lens and want to spend the same money, then the Sigma 18-50mm f/2.8 EX DC Macro gets the best reviews, but I have not used it.

Also consider buying a second body so you can have two lenses mounted and ready to go at all times. Besides, it's insurance for when the first camera gets dumped into the punch bowl.

The second image is lovely... but then I'm a sucker for mist.

I replaced the kit with the DA 16-45mm. It has served me very well so far -- my unease about the quality of my pictures taken with the kit lens has evaporated. Though I think I am more of a prime photographer I'd recommend this as an upgrade to the kit without hesitation.

An extra quote snuck in -- fixed!