Pentax SMC FA 645 25mm f/4 SMC AL IF SDM AW Lens
The Pentax 645 25mm f/4 is a 25mm f/4 lens designed for Pentax 645 mount cameras. Check GearFocus for current availability, with buyer protection on every purchase.
Pentax SMC FA 645 25mm f/4 SMC AL IF SDM AW Lens
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Lens Overview — Pentax 645 25mm f/4
Key Features — Pentax 645 25mm f/4
25mm Medium Format Prime: Fixed 25mm focal length covers the full Pentax 645 medium format frame, delivering an ultra-wide perspective suited to landscape, architectural, and environmental photography.
Pentax 645 Native Mount: Designed exclusively for the Pentax 645 system, providing full electronic communication between lens and body for metering and autofocus.
SDM Autofocus Motor: Built-in Supersonic Drive Motor enables quiet, responsive autofocus alongside manual focus operation for flexible shooting across different situations.
Internal Focus Design: IF (Internal Focus) mechanism keeps the overall lens length constant during focusing, which is useful when using front-mounted filters.
All-Weather Construction: AW (All-Weather) sealing provides dust and moisture resistance, making the lens suitable for outdoor use in challenging conditions.
Aspherical Lens Element: AL (Aspherical Lens) element helps reduce distortion and aberrations commonly associated with wide-angle lenses at this focal length.
Lens Specifications — Pentax 645 25mm f/4
| Spec | Detail |
|---|---|
| Use Cases | Landscape, Architecture, Travel |
| Lens Type | Wide-Angle |
| Format | Medium Format |
| Zoom/Prime | Prime |
| Focal Length | 25mm |
| Maximum Aperture | f/4 |
| Camera System | Medium Format |
| Lens Mount | Pentax 645 |
| Autofocus | Yes |
| Focus Type | Auto, Manual |
| Image Stabilization | None |
| Filter Thread | 82mm |
Description — Pentax 645 25mm f/4
The Pentax SMC FA 645 25mm f/4 is a prime wide-angle lens built exclusively for the Pentax 645 medium format camera system. Operating at a fixed 25mm focal length with a maximum aperture of f/4, it provides a wide field of view suited to landscape, interior, and architectural work on medium format. The lens uses the Pentax 645 mount for native system integration and supports both autofocus and manual focus switching, offering operational flexibility across different shooting scenarios.
With an 82mm filter thread, it accommodates a wide range of front-mounted filters. At 1040g, the lens has the substantial build expected of a medium format prime. No image stabilization is included, making stable support more important when shooting at slower shutter speeds. This lens is a dedicated option for Pentax 645 system photographers looking for a wide-angle prime with autofocus capability.
Pros — Pentax 645 25mm f/4
- ✓Native Pentax 645 mount ensures full compatibility with Pentax 645 system cameras
- ✓25mm prime focal length delivers consistent wide-angle perspective on medium format
- ✓Supports both autofocus and manual focus operation for shooting flexibility
Cons — Pentax 645 25mm f/4
- ✗No image stabilization, which can limit handheld shooting in lower light conditions
- ✗1040g weight makes this a heavy lens to carry for extended shoots
- ✗f/4 maximum aperture is relatively modest for low-light or shallow depth-of-field work
Videos — Pentax 645 25mm f/4
Pentax 645D Hands-On Field Test — TheCameraStoreTV