Originally posted by DSLRnovice But I am not sure if the M20 will offer better IQ than the DA16-45.
I've owned both lenses, but I've only shot the DA 16-45 on APS-C. On APS-C, I much preferred the M 20/4. Not that there's much difference in measurable qualities between the lenses. They both exhibit comparable sharpness (at least on APS-C). But I found that, while I was initially impressed with the DA 16-45 (it's sharp all the way to the corners on APS-C), the images I got from the lens didn't wear well over time. Something indefinable and immeasurable but very real in the color contrast and rendering was missing. Whereas I had the opposite reaction with the M 20/4. It doesn't bowl you over at first either with sharpness, contrast, or saturation, but there is something subtle and life-like in the rendering and colors that you begin to appreciate more and more over time. Whoever designed the M 20/4 had a finely developed aesthetic taste; whereas the DA 16-45 was the first lens Masakazu Saori designed to production, and (I suspect) suffered from his lack of experience (he was barely out of college at the time). Saori would later go on to become one of the pre-eminent lens designers in the world, but he was hardly that in 2003 when he was working on the DA 16-45.
A couple of images from the M 20/4, shot with the K-1: