I had been shooting macro with a pentax-m 100mm f4 until I picked up a raynox 150. It mounts on any of my four lenses and gives me macro sharpness with more flexibility than just one dedicated macro lens. On the Sigma 30mm 2.8 it produces sharp rich shots, as can be seen in the first two above. The latter two were shot with the Pentax-m 100 2.8. I don't see a fall off in light or a reduction in lens speed. Marvelous solution that also works well with legacy primes.