To be blunt, the Panasonic Leica 42.5mm f/1.2 is simply brilliant when it comes to sharpness. Images are very sharp right from f/1.2 over the majority of the frame, with just a little corner softening at wide apertures. When stopped down, the lens becomes simply blisteringly sharp, with center resolution that almost certainly outresolves the sensor. The edges and corners aren’t quite as sharp as the center, especially at closer focus distances, but they are more than good enough for any purpose. Once you start focusing out at further focus distances, even the corners sharpen up nicely.
Quite simply, you won’t be disappointed, whether shooting at f/1.2 or f/8. The image on the right is taken at f/1.2. Click for the full size image and press the green arrow at the bottom of the screen to view at 100%.
With a large f/1.2 aperture and the short telephoto length, the Nocticron is a natural fit for portraiture, as well as other applications where shallow depth of field are desirable. In what is actually rather unusual for a lens that is this sharp wide open, the Leica 42.5mm f/1.2 maintains very smooth pleasing bokeh. Specular highlights are evenly illuminated, with no bright edges or onion ring artifacts. Overall, even at a distance, bokeh remains relatively neutral. There are some cases where the green fringing that can occur behind a subject can introduce some color artifacts in the bokeh, most notably in busy backgrounds such as sticks or shrubs. All in all, the bokeh out of the Nocticron is excellent.
Color, Contrast and Chromatic Aberration
While the Panasonic Leica 42.5mm f/1.2 is certainly sharp and has very nice bokeh, perhaps the most remarkable thing about the lens is the very high level of contrast and rich color saturation the lens maintains even at maximum aperture. Even the very best ultra-fast lenses generally have lowered contrast at the widest apertures, but the Leica here maintains high contrast and vibrant color even at f/1.2. Images have a definite pop to them and this gives the 42.5mm a unique look among fast lenses.
One area where the Nocticron does stumble slightly with chromatic aberrations. While still relatively well controlled for a fast lens, the 42.5mm shows some minor lateral chromatic aberrations, but more noticeable longitudinal chromatic aberrations. This can result in magenta and green fringing in front of and behind the point of focus. Some purple fringing can also occur in certain circumstances. It’s not a perfect performance here by any measure, but overall, these levels are still relatively low for a lens of this type.
Distortion, Flare, Vignetting and other Aberrations
The 42.5mm Nocticron has just a hint of barrel distortion, but nothing that will generally be visible in typical light. I did not notice any issues with flare during my time shooting with the lens. No real loss of contrast is evident in backlit situations and complex flare is kept under control
The lens does show notable corner shading at maximum aperture. When used for portraits, I actually like a little bit of vignetting in a lens like this, so for me personally, I don’t mind vignetting at f/1.2. Stopping down to f/2 cuts down vignetting significantly. Most fast telephoto lenses have some residual spherical aberration that shows as a light glow at wide apertures. The Panasonic Leica 42.5mm, however, shows extremely low levels of spherical aberration even wide open. This is a rather remarkable performance, especially considering how smooth the bokeh is.