K3 with older lenses

When I would be to buy a new K3 will I still be able to use my older lenses with it or will the sensor show the limits of these lenses?
I mainly use the Pentax DA16-45, DA50-200 and my Sigma 50-500.
I would like to upgrade to a newer body but I don't feel much like buying new glass to go with it.

While the K3 might be able to go beyond the limits of many lenses they'll still work OK with it. It's only in pixel peeping that you'll see the limits - I doubt you'll print anything bigger than A3.
The lenses you list are good - perhaps not quite as good as the limiteds or star lenses, but I'm told you'd have seen some of the benefits of them even on the likes of the K20d.
Many people still like the Takumar 55 even though lenses have inproved a lot from when it was made, don't discount old glass it still often gives great results!

Your lenses are pretty much up to date, so I can't see a problem. I've used the K3 with a Sigma 150-500 and that combination works fine.

I've used the Pentax DA16-45, DA50-200 and Sigma 10-20 F3.5 24-70 F2.8 and 150-500 on my K3. It's only the DA50-200 which shows it's weakness when you zoom in to view the image, I have found it needs to be stopped down to get good results. The others work well, I was very supprised how well the 16-45 works give the age of design.

I have used numerous lenses on my K-3 and it definitely responds to high quality glass. I think the lenses mentioned will be fine, it's also worth checking out some of the older classics, for example I have a Pentax-M 28mm F3.5 which works particularly well on the K-3. It's a very sharp little lens and the K-3 makes the most of it.

When you have your K-3 it is worth trying to acquire some higher quality glass, the resolution and detail available in the K-3's images can be quite startling, but only with the best lenses.

Regards
David

Thanks for the replies, it pretty much confirms the ideas that had already.
Replacing the 50-200 won't be such a big deal I think.
So it will be time to start saving and trying to convince SWMBO that I need a new DSLR after 6 years

I pretty much use the DA*16-50/2.8 & Sigma 70-200/2.8 APO EG on my K3 and sometimes with the FA43 &77. I recently got the FA*85/1.4 and cannot wait to try it out.