The Pentax 100mm Macro looks like an old-school lens, with its lockable aperture ring at the back and a huge 'clamp' switch on the side, for locking focus.

I've had the F, FA, and DFA versions of the 100mm macro. Whereas the FA was a bit lighter and made of plastic, there is a weight to the F that surprised me (maybe because it's made of metal... don't let the grey color fool you, this is a hefty metal beast). It feels solid when mounted on my k-5.

IQ; autofocus

narrow focus ring; weight

Pentax 100mm f/2.8 Macro SMC P-FA review by kiwijono

I was worried about the purchase at the time (you can never be sure of what you are going to get with online auctions) but now I realise I got a bit of a bargain. The focus limiter is a very useful feature and I now would not like to be without it (pity DFA macros don't have one).

Very sharp; focus limiter; nice feel to it; good bokeh

Spoils the others lenses

8 Macro is an exceptionally good lens. Well built and weather sealed

The Pentax 100mm f/2.8 Macro is an exceptionally good lens. Well built and weather sealed. It is absolutely tack sharp at all focal lengths and great as a general lens not just Marco. It works perfectly with my Full Frame Pentax K-1 with no vignetting.