Portrait At-a-Glance Comparison (Upper Body Framing)
| Optical & Portrait Metric | Nikon NIKKOR Z 40mm f/2 | Nikon NIKKOR Z 50mm f/1.8 S | What It Means in Practice |
|---|---|---|---|
| Upper-Body Working Distance | 1.62 m | 2.01 m | The Nikon NIKKOR Z 50mm f/1.8 S requires 0.4 m more room behind you for the same subject size. |
| Background Field of View (Compression) | 50° | 41° | Nikon NIKKOR Z 50mm f/1.8 S shows a 18% narrower slice of the room behind the subject (41° vs. 50°), isolating them against a cleaner background. |
| Entrance Pupil Diameter | 20.0 mm (f/2) | 27.8 mm (f/1.8) | Distant background blur discs are 39% larger on the Nikon NIKKOR Z 50mm f/1.8 S. |
| Corner Bokeh Roundness (90% Field) | 86% (-0.6 EV) | 69% (-0.5 EV) | Nikon NIKKOR Z 40mm f/2 keeps significantly rounder bokeh balls into the corners wide open (86% vs. 69% roundness). |
| Effective Focal Length (Breathing) | 39.0 mm (-2.4%) | 48.6 mm (-2.9%) | Nikon NIKKOR Z 40mm f/2 frames like 39.0 mm (-2.4%) at 1.6 m; Nikon NIKKOR Z 50mm f/1.8 S frames like 48.6 mm (-2.9%) at 2.0 m. |
| Depth of Field (Sharp Zone) | 29 cm (1.49 m – 1.78 m) | 26 cm (1.89 m – 2.15 m) | The Nikon NIKKOR Z 50mm f/1.8 S has a 11% thinner focus zone (29 cm vs. 26 cm)—requiring more precise eye focus. |
| Minimum Focus Distance | 0.29 m | 0.4 m | Nikon NIKKOR Z 40mm f/2 focuses 11 cm closer (0.29 m vs. 0.4 m) for tighter close-ups. |