The Pentax 50mm F1.7 is the standard lens partner for your K1000 or used on your Sony full frame E-mount via PK-E adapter.  At max aperture F1.7 an excellent choice for light challenged scenes.  Optically in good condition and cosmetically excellent.  The build quality of these lenses is superior to a lot of moderrn glass. . .You can buy this lens for your K-mount Pentax or choose the option of adding a K&F precision PK-E adapter which enables this lens to be mounted on Sony E-mount, focus peaking cameras. Both lens caps supplied.