SG-Image AF 55mm F/1.8 STM
Short telephoto prime lens • Digital era
- Announced:
- · November 2024
- Production status:
- ● In production
- Country of design:
- · PRC (People's Republic of China)
- Original name:
- · SG-image AF 55/F1.8 STM
- Class:
- · Fast APS-C-format short telephoto prime lens
Specification
| Optical design: | |
| APS-C | |
| 55mm | |
| F/1.8 | |
| 10 elements in 8 groups | |
| 5 HRI | |
| Fujifilm X | |
| Nikon Z | |
| Sony E | |
| 29° (Fujifilm X APS-C) | |
| 28.8° (Nikon Z APS-C) | |
| 28.8° (Sony NEX/a/ZV APS-C) | |
| On Fujifilm X APS-C [1.52x] cameras: | |
35mm equivalent focal length: | 83.6mm (in terms of field of view) |
35mm equivalent speed: | F/2.7 (in terms of depth of field) |
| On Nikon Z APS-C [1.53x] cameras: | |
35mm equivalent focal length: | 84.2mm (in terms of field of view) |
35mm equivalent speed: | F/2.8 (in terms of depth of field) |
| On Sony NEX/a/ZV APS-C [1.53x] cameras: | |
35mm equivalent focal length: | 84.2mm (in terms of field of view) |
35mm equivalent speed: | F/2.8 (in terms of depth of field) |
| Diaphragm mechanism: | |
Diaphragm type: | Automatic |
Aperture control: | None; the aperture is controlled from the camera |
| 9 (nine) | |
| Focusing: | |
| 0.60m | |
| <No data> | |
Focusing modes: | Autofocus (AF), Manual focus (MF) |
Autofocus motor: | Stepping motor |
Manual focus control: | Focusing ring |
Focus mode selector: | None; focusing mode is set from the camera |
Manual focus override in autofocus mode: | Determined by the camera |
| Optical Image Stabilizer (OIS): | |
| - | |
| Physical characteristics: | |
| 365g (mount not specified) | |
| ⌀69×78mm (mount not specified) | |
| - | |
| - | |
| Accessories: | |
| Screw-type 58mm | |
| Bayonet-type square | |
| Not available |
Source of data
- Manufacturer's technical data.
From the editor
The first autofocus lens from SG-Image. Despite the fact that this lens is a budget model designed for APS-C mirrorless cameras, it has a rather complex optical design consisting of 10 elements and including as many as 5 high refractive index elements. This could not but affect the weight and length, which are not the lowest for a portrait lens with a speed of F/1.8. The lens barrel is metal and quite ascetic: there is no aperture ring or focus mode switch.
Although the lens does not have a record-breaking speed, it is enough to shoot in low light conditions, as well as isolate the subject, smoothly blurring the background. When stopping down, 9 aperture blades will keep the out-of-focus highlight's a more rounded shape.
The lens is equipped with a stepping motor, providing quiet and fast automatic focusing. The closest focusing distance is 0.6m. In practice, when shooting portraits (head and shoulders / head and chest), focusing distances of 1.5-2m are considered optimal.
The lens uses 58mm filters and a square hood, which is rare outside the Fujifilm system.
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