Opticallimit tested the Olympus 17mm f/1.2 PRO lens and writes:
The Olympus M.Zuiko 17mm f/1.2 PRO may not be quite as stellar as the 45mm f/1.2 PRO but it doesn’t mean that it’s a dud. It’s far from it. The resolution characteristic doesn’t show any weaknesses but there is a drop between the center and border/corner quality. The center is very good to excellent at f/1.2 whereas the borders are more in the good to very good range. That’s actually impressive at f/1.2 just to stress this. Stopping down boosts the center but the outer image field … not so much. Lateral CAs are low though so this contributes to the high sharpness perception. Auto-correction takes care of image distortions which are clearly present in RAW files. The original vignetting is quite high at f/1.2 but, once again, auto-correction will come to the rescue here for most users anyway.A real highlight (no pun intended) is the quality of the bokeh which is very smooth and that’s especially impressive considering the wide-angle nature of the lens. That’s for the technical bokeh at least. If you had a look at our sample images, you may, however, recognizes that the sheer ability to produce a shallow depth-of-field is rather limited. On the 45mm f/1.2 this isn’t so much of an issue simply because of its relatively long focal length but the 17mm f/1.2 doesn’t have this advantage. In terms of depth-of-field we are talking about a “34mm f/2.4” (in full format terms) here so keep that in mind.The build quality of the Zuiko is excellent thanks to a tightly assembled all-metal and sealed construction. It’s even freezeproof down to -10C which is something few other manufacturers can claim for their professional-grade lenses. Whether you like the focus-clutch mechanism for switching between AF and MF is a matter of taste. It is quite inevitable to shift the focus when doing the switch. However, the clutch does give you a mechanical focus coupling with a distance scale which is rare on mirrorless lenses. Most will still prefer to use the MSC autofocus and both its speed and accuracy are very high.The Olympus M.Zuiko 17mm f/1.2 PRO is a pricey lens. If high speed and a great bokeh are your priorities, it is an obvious mainstream choice. As far as sharpness goes, there are more affordable options available that can give you just as much.