Olympus m.ZD 17mm f/2.8 pancake lens

introduction

one of the 1st Olympus a brief catalogue of Micro Four Thirds lenses to be produced and thus has an older, slower AF mechanism and the optic quality is very average for a prime lens although central sharpness is very good.
very compact, cheaper and with nicer bokeh than the legendary Panasonic Lumix 20mm f/1.7 pancake lens but obviously is f/2.8 rather than f/1.7
users should consider the cheap but excellent Sigma 19mm f/2.8 EX DN asph lens for Micro Four Thirds as an alternative to this lens
although I own this lens, personally I would not advise users to buy it - get one of the above lenses instead
only slight (0.8%) barrel distortion when corrected by Olympus cameras but RAW distortion is quite bad at 4.5%
vignetting is mild at 0.8EV
substantial CA which is uncorrected (2.2px at f/2.8 increasing to 2.8px at f/5.6, and averages 3px at the edges)
prone to lens flare without a hood when shooting into bright lights
very sharp in the centre but borders only average and best at f/4 while corners are soft wide open and reach average at f/5.6

17mm focal length = 34mm in 35mm film terms = very nice for street photography
f/2.8-f/22 aperture = an almost an extra stop light and DOF performance compared to the kit lenses
37mm filter size - same as the Olympus m.ZD 45mm f/1.8 portrait lens and the Olympus 14-42mm f/3.5-5.6 IIR
closest focus 20cm
lens extends slightly when powered up
6 elements in 4 groups = high optical quality with reasonable bokeh
71g
57mm x 22mm long (pancake)