Originally posted by gerardbaron The old Tamron 70-200 macro f:2.8. Try to find one if it is still available.
Work very good and very sharp on a K-1 II.
It is a zoom but it is NOT macro. There are several models with different optic formulas, mine (Sigma 70-200mm f/2.8 II Ex HSM Macro DG) goes to about 1:3.
I own one Sigma 180mm F3.5 APO EX DG IF macro, it is a very good macro lens but very expensive (and of course it is no more produced).
I also own one Irix 150mm F/2.8 macro, it is a very good macro lens too, and affordable (and it is still in production). Its bokeh is awesome.
By the way, there are cheaper options, for example if you own a PENTAX DA* 300mm F4 sdm ED [IF], you could buy a Nikon 6T close up, then you would reach 1:1 (about 1.1:1 if I am not wrong) and get a huge working distance: 28cm @ 1:1.
Irix 150's working distance is about 17.2cm @ 1:1.
Sigma 180's working distance is about 23.1cm @ 1:1.