Leica 75mm F1.25 Noctilux-M
Leica 50mm F0.95 Noctilux-M
The physical differences is obvious with the Leica 75mm F1.25 Noctilux-M ASPH been the larger and heavier lens of the two. The Leica 75mm F1.25 Noctilux-M ASPH measured at H91mm x W74mm, which is taller and slightly wider than the Leica 50mm F0.95 Noctilux-M ASPH measured at H75mm x W73mm. The 75mm Noctilux is about 300 grams heavier at 1055g compared to 700g weight of the 50mm Noctilux. The build finish for both lenses is black anodized but the retractable hood design is different, as the 75mm Noctilux has twisting out hood compared to the 50mm Noctilux with sliding out hood design.
The Leica 75mm F1.25 Noctilux-M ASPH has a maximum aperture of F1.25 whereas the Leica 50mm F0.95 Noctilux-M ASPH has a maximum aperture of F0.95. However, due to the longer focal length of the Leica 75mm F1.25 Noctilux-M ASPH and shorter minimum focusing distance at 0.85m resulting both lenses with similar shallow depth of field. Bokeh produced by both lenses are exceptionally smooth and pleasant with the 75mm Noctilux offers even smoother bokeh due to the design with 11 diaphragm blades, as the number of diaphragm blades is not specified for the 50mm Noctilux.
The Leica 75mm F1.25 Noctilux-M ASPH Lens released in 2018 has the benefit of the latest optical technology compared to the Leica 50mm F0.95 Noctilux-M ASPH designed almost a decade ago back in 2008. The Lens design is very similar for both Noctilux incorporating complicated optical composition with two aspherical elements to ensure maximum sharpness and optimal performance. As a result, the sharpness is equivalent but the chromatic aberration is significantly reduced on the 75mm Noctilux. Chromatic aberration or purple fringing was a common issue for the 50mm Noctilux and this has been solved with the newer lens design consisting of low dispersion glass and anomalous partial dispersion.
Since I have been a long time user of the Leica 50mm F1.4 Summilux ASPH Lens that shared many similarities with it’s bigger brother, the Leica 50mm F0.95 Noctilux ASPH Lens. Whereas the Leica 75mm F1.25 Noctilux ASPH Lens is an entirely different focal length with improved lens design.
During practical use, the Leica 50mm F0.95 Noctilux Lens provides marginal improvement in optical performance over the amazing Leica 50mm F1.4 Summilux Lens but at a significant increase in size and weight. In contrast, the Leica 75mm F1.25 Noctilux Lens not only provides a different focal length to the Leica 50mm F0.95 Noctilux Lens but with improved sharpness and bokeh quality especially when shooting wide open.
(Bokeh vs Sharpness)