A lens that carries all the glamour of the 85mm f/1.2, but with the ease of construction of the 50mm standard is an exciting prospect. Damien Demolder tests Panasonic’s Leica DG Nocticron 42.5mm f/1.2 Asph Power OIS
Panasonic Leica DG Nocticron 42.5mm f/1.2 Asph Power OIS review – Image quality
Image: Vignetting at f/1.2
How you rate the image quality this lens produces will depend very much on what you are using it for. If you are expecting technical accomplishment at wide apertures so you can record flat documents in low light, you might be unimpressed. However, if you are in the business of creating atmospheric and romantic impressions of life and your fellow humans, you may develop an entirely different opinion.
In fact, the quality characteristic is very much in line with what we might expect from a wide-aperture moderate telephoto – it vignettes when used wide open and there is some variation in sharpness across the frame. When using the lens at f/1.2, I experienced the interesting combination of corner shading and centre brightening – in which the edges of the frame are recorded darker than they should be, and the middle of the picture actually becomes brighter than the exposure should provide. This hotspot dissipates gradually, and disappears by f/5, and corners even out for all intents at about the same time. Part of the reason for this uneven illumination is the degree of ‘out of focus’ that the lens can achieve, especially with close subjects. The vignetting is hardly noticeable when the focus point is in the distance, but the optical disruption is dramatic when we concentrate on a subject at around 6ft (2m).
At the widest aperture setting the nine iris blades sit redundant in the body of the barrel and we
are treated to a completely circular opening. Even when those blades come into play, though, out-of-focus highlights are reproduced as beautiful round discs, and in most cases with very little chromatic fringing on their edges. I’m also pleased to say that chromatic separation is not a feature of this lens, as it is in so many others of this type, and even high-contrast, defocused edges are rendered clean. That’s quite an achievement, and makes the lens very usable.
Wide apertures produce remarkable sharpness at the edges of the frame, which is important for portraiture, and a great improvement over the sort of edge quality we might have expected.
It is no surprise that f/8 is the aperture that produces the best technical quality, and where we experience peak sharpness and the greatest degree of evenness of both sharpness and illumination.
Tested on a Panasonic Lumix DMC-GX7
The test charts for this lens are quite misleading with regard to its qualities. The degree of centre brightening creates the impression of lower contrast, and the charts interpret that as lower resolution, and describe a lens that, when used at wider apertures, is sharper at the edges than it is in the middle. In use, that effect cannot be seen, although it is noticeable that best resolution comes from f/2 and improves to f/8, then drops off. The uneven illumination is highly
visible, but again this is resolved by f/5.6-8.