I own a Pentax K1000...it was used when I bought it, but it is still in pretty good condition. I am looking to get a zoom lens. I was wondering what focal length would be useful or good to use... (I don't really need it for any particular reason- just for fun)... And if you think I should just invest in a new camera instead of spending money on a lens (but I think I am going to shop ebay for either)... Any and all opinions are helpful! Thanks so much... Lindsey Ps... like would a PENTAX M 135mm f3.5 SMC LENS work??