(text by P.S.) Good overall performance, some barrel distortion in wide end, but sharpness is very good in all focal lenghts and apertures. Color reproduction is a bit \'dim\' compared to EF-series lenses, but as the lens is very small it\'s not very prone to flare. I use Lensmate lens barrel on it, Lensmate is used as filter host and it also protects the lens from physical damage - the G1 extends the lens when it\'s powered, and the whole system is a bit wobbly and feels very fragile. Excellent price/performance ratio!