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Sigma 4.5mm f/2.8 EX DC HSM Fisheye lens for Sony A-Mount
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$164.00
Sigma 4.5mm f/2.8 circular fisheye built for APS-C shooters
Circular fisheye lenses occupy a specific niche, and the Sigma 4.5mm f/2.8 EX DC HSM is one of the proven options for Sony A-mount APS-C bodies. At 4.5mm, it produces a full circular image within the frame, not a frame-filling diagonal fisheye effect. The f/2.8 maximum aperture gives you low-light access that most fisheye lenses don't offer, and the 14cm minimum focus distance lets you push subjects to the edge of the circular field for exaggerated perspective effects.
The HSM ultrasonic motor drives fast, quiet autofocus with full-time manual override available without switching modes. Internal focusing keeps the front element stationary, which matters since fisheye front elements are inherently exposed and difficult to filter. Sigma addresses that with a rear gelatin filter slot. The 13-element, 9-group optical formula incorporates SLD glass to manage chromatic aberration across the extreme field of view. At 470g, the lens handles well on a standard A-mount body without front-heavy imbalance.
For Sony A-mount shooters who need a true circular fisheye, this lens covers an use case that almost no other option in the mount ecosystem addresses directly.
Who It's For
Night sky and planetarium-style photographers benefit from the f/2.8 aperture and circular image format, which suits all-sky capture in a single frame. Architectural and interior photographers working in tight spaces will use the 14cm minimum focus distance to fill the circular field with a subject just inches from the lens. Creative and fine art shooters drawn to the spherical distortion of a true circular fisheye, than a diagonal fisheye, get a distinct look that no rectilinear wide angle replicates. Sony A-mount system users specifically will find the native mount integration with HSM autofocus a practical advantage over adapted alternatives.
Key Features
- 4.5mm f/2.8 circular fisheye for Sony A-mount APS-C bodies
- 14cm minimum focus distance for exaggerated perspective effects
- HSM ultrasonic motor with full-time manual focus override
- 13-element, 9-group optical design with SLD glass
- Internal focus mechanism keeps front element stationary
- 470g body with 76mm diameter, rear gelatin filter slot
FAQ
- What's the field of view on this 4.5mm fisheye?
- It produces a full circular image within the frame-the entire circular fisheye effect fits inside your sensor, not edge-to-edge across it. This is different from diagonal fisheyes that fill the frame.
- Can you autofocus with this lens, and how fast is it?
- Yes, the HSM ultrasonic motor delivers fast, quiet autofocus. You get full-time manual override without switching modes, so you can fine-tune focus whenever you need to.
- How close can you focus with this lens?
- Minimum focus distance is 14cm, which lets you position subjects near the circular field edge for extreme perspective distortion.
- Why does this lens have a rear gelatin filter slot instead of a front filter thread?
- The front element is inherently exposed in a circular fisheye design and nearly impossible to filter conventionally. The rear gelatin filter slot solves that without adding bulk or optical complications.
- What's the weight and size trade-off here?
- At 470g with 76mm diameter and 78mm length, it balances portability with optical complexity. The internal focusing design keeps the front element from extending, which helps with the exposed front element issue.
- Does this lens have image stabilization?
- No, it does not. You'll rely on shutter speed, aperture, and ISO to manage exposure in low light-though the f/2.8 maximum aperture gives you more options than most fisheyes at this focal length.
| Specification | Value |
|---|---|
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Mount | Sony/Minolta Alpha (A-Mount) |
| Stabilization | No |
| AF System | Yes |
| Min Focus Distance | 0.14 m (5.31") |
| Lens Type | Prime |
| Motor Type | Ultrasonic (HSM) |
| Full Time Manual | Yes |
| Focus Method | Internal |
| Elements | 13 |
| Groups | 9 |
| Special Elements Coatings | SLD glass |
| Diaphragm Blades | 6 |
| Aperture Ring | No |
| Distance Scale | Yes |
| DOF Scale | Yes |
| Diameter | 76 mm (3") |
| Length | 78 mm (3.06") |
| Color | Black |
| Filter Notes | Rear gelatin filter |
| Weight | 470 g (1.04 lb) |
This description was generated using AI based on KEH's internal product standards, product expertise, and knowing what customers care about most. While we strive for accuracy, details may vary by individual item.
| Brand Name | Sigma |
|---|---|
| Focus Type | Autofocus (lens motor) |
| Lens Mount | Sony A & Minolta A |
| Lens Type | Wide-Angle |
| Max Focal Length | 4.5mm |
| Min Focal Length | 4.5mm |
