thanks for all your feedback, youv really cleared that up for me!

incase u were wondering im actually considering the k100d rather than the non existant k100s lol however im sure you all already knew that

hey everyone, im new to photography and am interested in buying a new DSLR camera. Recently iv inherited some old school camera gear off my now blind grandfather including :
-pentax k1000 asahi camera
-SMC pentax-m 1:2 50mm lens
-makinon 1:4.5 f=75-250mm lens
-2x teleconverter

I think that both lenses and the teleconverted are k-mounted. Im interested in buying a k100s for my first dslr because i figured it would be handy to be able to use the lenses i already have (particularly the 75-250mm).

However I read on the pentax website that k mounted lens are usable with some limitations on the k100s. Further research revieled that the lenses are only useful at full apeture. i know what this means, but i dont understand the its repercusions. how will that effect my photos? will it mean that the lens will only be usefull under certain lighting conditions? is it worthwhile to choose pentax over another brand just to be able to use k mounted lens, even though the lenses need to be at full apeture (aparently)?

any help would be really appreciated
thanks
Matt