My lens lust didn't stop there though! The next purchase was an AML ( Apochromatic Macro Adapter ) extenstion for the sigma 70-300. It reduces the minumum focus distance, and transforms the reproduction rate from 1:2 to 1:1. This means that with the adapter it should be possible to fill the frame with an object the same size as the sensor ( 23.7mm x 15.5mm ). There a number of problems with this however, it's not the sharpest combo in the world, and the DOF is incredibly shallow. Anyway, its useful to have as an option if you can't afford a dedicated macro lens. I think that ive managed to squeeze off a few decent shots.