Full-Frame 35mm Sensor (36×24 mm)
Direct Answer
The Full-Frame 35mm Sensor (measuring 36.0 × 24.0 mm with an active surface area of 864.0 mm² and a 43.27 mm diagonal) is the universal baseline benchmark in digital photography, defined with a 1.0× crop factor. Derived from the standard 35mm 135 still film format established by Oskar Barnack's Leica I in 1925, all focal length equivalents and field-of-view calculations are calibrated against it.
Source: CIPA (Camera & Imaging Products Association) Standards / ISO 12232
Specs
| Width × Height | 36.0 × 24.0 mm (1.417 × 0.945 in) |
| Diagonal Dimension | 43.27 mm |
| Active Surface Area | 864.0 mm² |
| Crop Factor Benchmark | 1.00× (The reference baseline for 35mm focal length equivalence) |
| Native Aspect Ratio | 3 : 2 (1.50 : 1) |
| Standard Pixel Pitches (Modern) | 4.5 µm (45 MP — Nikon Z8/Canon R5) to 8.4 µm (12 MP — Sony A7S III) |
| Flagship Camera Implementations | Sony A7/A9/A1 series, Canon EOS R5/R6/R3, Nikon Z6/Z7/Z8/Z9, Panasonic Lumix S5/S1, Leica M/SL |
The 35mm Leica Heritage
In 1913, German optical engineer Oskar Barnack adapted $35\text{ mm}$ perforated movie film for still photography by turning the film path horizontally, creating a frame measuring $36 \times 24\text{ mm}$ with a $3:2$ aspect ratio. When digital sensors emerged, $36 \times 24\text{ mm}$ silicon dies became known as 'Full Frame', retaining the exact focal lengths, perspectives, and depth-of-field characteristics that photographers had used for a century.