Making the jump from purely mechanical film cameras to (if I want it)
fully automated digital, I certainly have a lot to learn. (My
original Ricoh (bayonet lenses compatible with Pentax) was purely
mechanical (except for the light meter). I used it for 17 years
then it was stolen. I then bought a similar model, which had one
automatic setting (set the opening by hand and it will set the
shutter speed automatically.)) As I said, lens compatibility was
my original reason to look at Pentax, but as I mentioned after
having looked what was possible for what I wanted to spend ($1000 or
so including lens), the Pentax offered so much bang for the buck
that it would have been my choice even without the possibility to
use my old lenses. I've never used autofocus. We'll see how it
works.

I'm sure I'll stick to the 18--55 lens which came in the
kit at first. My old 50 mm would be effectively 75 mm, so there might
be some specialised uses for it. My 80--200 would be effectively 120--300,
so might be useful for extreme telephoto shots. I'll probably by new
wide-angle, standard and telephoto prime lenses with time. (The newer
lenses are also smaller and lighter since the sensor on the Pentax, while
not as small is some, is smaller than 35 mm film. However, cropped older
lenses might give a better image. Of course, the new ones have autofocus
etc.)

One of the nice things about the K10D is that it has a nice viewfinder.

I might keep it for 15 years! At home, I have computers from the 1989--1995
time frame still running! (Not as museum pieces, but as always-on do everything
servers: web server, my own SMTP server, FTP server, as well as for interactive
use like browsing the web, reading newsgroups, sending email etc and, yes,
even for computing (i.e. writing programs, compiling, linking and running them!).
They are not PCs, so I can actually run the newest, months-old operating system
on them.) As long as it does what I need, why upgrade? At some point, and for
me it might be now, cameras will reach the level of maturity of, say, electric
guitars 40 years ago, or violins 400 years ago.

I don't think I'll need more resolution. Noise---not sure yet if that will bother
me. I don't do much shooting at night, nor many action shots. The K10D has
a shake-reduction system, which should give about 3 more stops. (It is in the
camera body, not in the lens, so even old lenses benefit from it.) Dynamic range:
like noise, I'll have to see if it is good enough. A higher-resolution screen
might be better for previewing. (Live viewing? With a good viewfinder, why
worry about the lower resolution of a screen, sunlight making it invisible, or the
slight delay between what it shows and reality?) On the other hand, with 4 GB
cards, I can throw away only the obviously bad images and make a more informed choice
of what to keep later, on a high-resolution monitor; I can still have hundreds of
images on a card, and change cards if I need to. (The K10D can also shoot raw and
JPEG simultaneously, so one can use the JPEGs created on the fly to decide what to
keep, and if one wants to go back and really refine some of the images, one can then
process the raw files.) Like a mobile phone or a pocket calculator, I'm not sure if
smaller and lighter is an advantage (even though I have small hands), especially if
one is used to a SLR. Cheaper? Well, I've already bought the K10D!

http://www.pentaxslr.com/bodies/k10