Sony FE 50mm F1.2 GM vs. Sony Sonnar FE 55mm F1.8 ZA

Pick the 50mm f/1.2 if you want about 36% more background blur, pick the 55mm f/1.8 if you want less background blur. Compare both side by side.

Loading scene…
0%

Portrait At-a-Glance Comparison (Upper Body Framing)

Optical & Portrait Metric Sony FE 50mm F1.2 GM Sony Sonnar FE 55mm F1.8 ZA What It Means in Practice
Upper-Body Working Distance 2.01 m 2.21 m The Sony Sonnar FE 55mm F1.8 ZA requires 0.2 m more room behind you for the same subject size.
Background Field of View (Compression) 39° 37° Sony Sonnar FE 55mm F1.8 ZA shows a 5% narrower slice of the room behind the subject (37° vs. 39°), isolating them against a cleaner background.
Entrance Pupil Diameter 41.7 mm (f/1.2) 30.6 mm (f/1.8) Distant background blur discs are 36% larger on the Sony FE 50mm F1.2 GM.
Corner Bokeh Roundness (90% Field) 43% (-1.3 EV) 85% (-0.3 EV) Sony Sonnar FE 55mm F1.8 ZA keeps significantly rounder bokeh balls into the corners wide open (85% vs. 43% roundness).
Effective Focal Length (Breathing) 50.7 mm (+1.5%) 54.2 mm (-1.5%) Sony FE 50mm F1.2 GM frames like 50.7 mm (+1.5%) at 2.0 m; Sony Sonnar FE 55mm F1.8 ZA frames like 54.2 mm (-1.5%) at 2.2 m.
Depth of Field (Sharp Zone) 17 cm (1.93 m – 2.10 m) 26 cm (2.09 m – 2.35 m) The Sony FE 50mm F1.2 GM has a 33% thinner focus zone (17 cm vs. 26 cm)—requiring more precise eye focus.
Minimum Focus Distance 0.4 m 0.5 m Sony FE 50mm F1.2 GM focuses 10 cm closer (0.4 m vs. 0.5 m) for tighter close-ups.

Questions

Which blurs the background more, Sony FE 50mm F1.2 GM or Sony Sonnar FE 55mm F1.8 ZA?

At the same subject framing, distant background blur scales with the entrance pupil diameter (focal length ÷ f-number). Sony FE 50mm F1.2 GM at f/1.2 has a 41.7 mm entrance pupil, while Sony Sonnar FE 55mm F1.8 ZA at f/1.8 has a 30.6 mm entrance pupil.

How does working distance differ between Sony FE 50mm F1.2 GM and Sony Sonnar FE 55mm F1.8 ZA?

For an upper-body portrait, Sony FE 50mm F1.2 GM stands 2.01 m from the subject (sharp zone 17 cm, from 1.93 m to 2.10 m), whereas Sony Sonnar FE 55mm F1.8 ZA stands 2.21 m away (sharp zone 26 cm, from 2.09 m to 2.35 m).

How do the optical designs of Sony FE 50mm F1.2 GM and Sony Sonnar FE 55mm F1.8 ZA compare?

Sony FE 50mm F1.2 GM uses 12 elements in 9 groups (WO2017138250A1, effective focal length 50.7 mm at portrait distance). Sony Sonnar FE 55mm F1.8 ZA uses 7 elements in 5 groups (US20150092100A1, effective focal length 54.2 mm).

Explore individual lens ray-tracers

Head-to-head lens comparisons

All lens comparisons

Also see: depth of field, bokeh, crop factor, lens compression.