Having recently bought a brand new old stock K100D with DA 18-55 kit lens I soon added a Pentax-M 135mm f3.5 & Pentax-M 50mm f1.7. I tested them recently for sharpness using a garden ornament, the 'iron chicken' as the focal point. The kit lens was tried at 18mm & 35mm for comparison. I think from these results shot in RAW, the manual lens are well worth keeping and I'm impressed by my copy of the kit lens too. What do you think?
Order of sharpness
1. Pentax-M 50mm f1.7
2. Pentax-M 135mm f3.5
3. Kit lens @35mm
4. Kit lens@18mm