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Pentax 645 300mm f/4 SMC A* ED IF Lens

The Pentax 300mm f/4 SMC A* ED IF is a 300mm f/4 lens designed for Pentax 645 mount cameras. Used copies start from $265.19 on GearFocus, with buyer protection on every purchase.

Pentax 645 300mm f/4 SMC A* ED IF Lens

Pentax 645 300mm f/4 SMC A* ED IF Lens

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Pentax 645 300mm f5.6 SMC FA ED IF Lens

Condition: Excellent

Product Highlights

  • 300mm telephoto focal length
  • Extra-low Dispersion (ED) glass elements
  • Internal focusing mechanism
  • Super Multi Coating (SMC) for reduced flare

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Used Pentax 300mm f/4 SMC A* ED IF Listings on GearFocus

Pentax 645 300mm f5.6 SMC FA ED IF Lens
Pentax 645 300mm f5.6 SMC FA ED IF Lens

Excellent

$265.19

🚚 Free Shipping

Lens Overview — Pentax 300mm f/4 SMC A* ED IF

The Pentax 645 300mm f/4 SMC A* ED IF is a manual focus telephoto prime lens built specifically for the Pentax 645 medium format camera system. With a fixed 300mm focal length and a maximum aperture of f/4, this lens is designed to bring distant subjects into sharp focus on the larger medium format frame, making it well suited for portraiture, wildlife, and outdoor photography where subject reach matters. Being a prime lens, it offers a fixed perspective that encourages deliberate framing and composition.

Manual focus operation puts full control in the photographer's hands, which many medium format shooters find preferable for precise, methodical work. The lens accepts 77mm filters, a standard thread size that makes it easy to pair with a wide range of polarizers, ND filters, and other accessories. Weighing in at 1350g, this is a substantial piece of glass befitting its medium format heritage and telephoto reach.

There is no image stabilization, so a sturdy tripod or monopod is advisable when shooting at this focal length. Overall, it represents a capable and specialized telephoto option within the Pentax 645 ecosystem.

Key Features — Pentax 300mm f/4 SMC A* ED IF

300mm Medium Format Prime: Fixed 300mm focal length on the larger medium format frame delivers a long telephoto perspective with no optical compromises from zoom mechanics.

f/4 Maximum Aperture: Provides reasonable light-gathering capability for a medium format telephoto, allowing for subject separation and use in moderate lighting conditions.

ED Glass Element: Extra-low Dispersion glass minimizes chromatic aberration, helping to maintain edge-to-edge sharpness and color accuracy at long telephoto distances.

Internal Focus (IF): Focus is achieved without changing the physical length of the lens, keeping balance consistent and allowing filters to remain properly oriented.

SMC A* Optical Coating: Pentax's Super Multi-Coating on a premium A* designation lens reduces flare and ghosting while maximizing contrast and light transmission.

Pentax 645 Native Mount: Built specifically for the Pentax 645 system, ensuring full native compatibility with Pentax 645 and 645N film bodies as well as the 645D and 645Z digital bodies.

Lens Specifications — Pentax 300mm f/4 SMC A* ED IF

Pentax 300mm f/4 SMC A* ED IF full specifications
SpecDetail
Use CasesWildlife, Sports, Landscape
Lens TypeTelephoto
FormatMedium Format
Zoom/PrimePrime
Focal Length300mm
Maximum Aperturef/4
Camera SystemMedium Format
Lens MountPentax 645
AutofocusNo
Focus TypeManual
Image StabilizationNone
Filter Thread77mm

Description — Pentax 300mm f/4 SMC A* ED IF

The Pentax 645 300mm f/4 SMC A* ED IF is a telephoto prime lens designed for the Pentax 645 medium format camera system. With a fixed 300mm focal length and a maximum aperture of f/4, it provides a dedicated long-reach perspective suited for a variety of subjects where distance is a factor. This is a manual focus lens, placing full focusing control with the photographer — a characteristic that many medium format practitioners appreciate for its precision and intentionality.

The 77mm filter thread offers broad compatibility with standard photographic filters, while the 1350g build reflects the robust construction expected of a medium format telephoto. Image stabilization is not included, so steady support such as a tripod is recommended for consistent results at this focal length. As a prime, the 300mm delivers a single, fixed angle of view on the medium format frame, encouraging thoughtful composition. This lens is a purpose-built tool for Pentax 645 system users seeking reliable telephoto reach.

Pros — Pentax 300mm f/4 SMC A* ED IF

  • ✓Fixed 300mm focal length delivers a dedicated telephoto perspective with no zoom compromise
  • ✓Maximum aperture of f/4 provides reasonable light gathering for a medium format telephoto prime
  • ✓Designed specifically for the Pentax 645 mount, ensuring native compatibility with Pentax 645 system bodies

Cons — Pentax 300mm f/4 SMC A* ED IF

  • ✗Manual focus only — no autofocus support, which may slow down shooting in fast-paced situations
  • ✗No image stabilization, making a tripod or monopod strongly advisable at 300mm
  • ✗Weight of 1350g makes this a heavy lens for handheld use over extended periods

Resources & Downloads — Pentax 300mm f/4 SMC A* ED IF

Manuals & Guides

Frequently Asked Questions — Pentax 300mm f/4 SMC A* ED IF

Is this lens compatible with Pentax 645 digital bodies?+
This lens uses the Pentax 645 mount, so it is designed for the Pentax 645 medium format camera system. You should verify compatibility with your specific body, as mount-to-body fit can vary across different generations of Pentax 645 cameras.
Does this lens have autofocus?+
No, this lens is manual focus only. There is no autofocus mechanism, so all focusing must be done by hand using the focus ring.
What filter size does this lens use?+
The lens has a 77mm filter thread, which is a common size that works with a wide variety of filters including polarizers and neutral density filters.
Does the lens include image stabilization?+
No, image stabilization is listed as None in the specifications. When shooting at 300mm, using a tripod or monopod is recommended to minimize camera shake.
How heavy is this lens?+
The lens weighs 1350g, which is substantial. This is worth factoring in when planning handheld shooting sessions or when selecting a tripod head with adequate load capacity.

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