offers faster, more silent and much less stuttering AF and shallower depth of field (DOF) thanks to the wider aperture, and with closer focus than the Panasonic Leica DG Summilux 25mm f/1.4 ASPH lenses when both are used on an OM-D camera but there is more vignette effect of bokeh circles in periphery making them more oval in shape
at aperture wider than f/5.6 is sharper in the centre but may be less sharp in the edges at comparable apertures at infinity, but sharper again when compared at ~2m subject distances
heavier, larger, more expensive, and has MF clutch with nicer manual focus feel but is weatherproof and f/1.2 vs f/1.4
shallower DOF, better bokeh, greater subject magnification despite both close focus is 30cm
25mm f/1.8 is more fun as lighter, smaller, much less expensive, good optics, 1 stop less shallow DOF but 0.3EV less light transmission, but if you want the shallow DOF then go for the f/1.2
“It is the first standard lens from ANY system I’ve used wide open that can compete with the Leica in relation to the sharpness, micro contrast and creamy bokeh. But when you factor in the speed and accuracy of its AF using eye recognition and IBIS, you have a system that is so much more useable than anything on the market. Instead of continually concentrating on achieving a sharp image, I can now just concentrate on the light and the subject, capturing any nuances of expression, focussing on the emotional rather than the technical. That’s why I’m selling my Leica equipment.”