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Pentax 26555 smc FA 645 400mm ED [IF] Lens — main product image
Pentax

Pentax 26555 smc FA 645 400mm ED [IF] Lens

★★★★★5.0 (3 reviews)

Achieve Unrivaled Detail with the Pentax 645 400mm Lens The Pentax smc FA 645 400mm f/5.6 ED [IF] lens is engineered for exceptional image quality and sharpness. Designed as a component for SLR cameras, this lens delivers outstanding performance in a sleek, black finish. Lens Structure: 7...

$898.49*
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*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

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Overview

Achieve Unrivaled Detail with the Pentax 645 400mm Lens

The Pentax smc FA 645 400mm f/5.6 ED [IF] lens is engineered for exceptional image quality and sharpness. Designed as a component for SLR cameras, this lens delivers outstanding performance in a sleek, black finish.

  • Lens Structure: 7 elements in 6 groups
  • Focal Length: 400mm (Fixed)
  • Lens Color: Transparent
  • Color: Black
  • Diameter: 8.3 cm
  • Filter Size: 77 mm
  • Product Length: 25.2 cm
  • Depth: 25.2 cm

Key Features

Product description : Pentax smc FA 645 400mm / 5.6 ED [IF] Component for: SLR

Lens structure (elements/groups): 7/6

Fixed focal length: 40 cm

Lens colour: transparent

Colour : black.Diameter: 8.3 cm.Filter size: 7.7 cm.Product length : 25.2 cm.Depth: 25.2 cm

Specifications

Product Type
Camera Lens
Brand
Pentax
Model
smc FA 645 400mm ED [IF] Lens
Component For
SLR
Lens Structure (elements/groups)
7/6
Fixed Focal Length
40 cm (400mm)
Lens Features
ED (Extra-low Dispersion), [IF] (Internal Focusing)
Lens Color
Transparent (glass), Black (body)
Diameter
8.3 cm
Filter Size
7.7 cm
Product Length
25.2 cm
Depth
25.2 cm

Pros & Cons

👍 Pros

  • Features an ED (Extra-low Dispersion) element, which typically helps in reducing chromatic aberrations for sharper images.
  • The [IF] designation indicates Internal Focusing, meaning the lens length does not change during focusing, which can be convenient.
  • Offers a fixed focal length of 400mm, ideal for specialized telephoto photography such as wildlife or sports.
  • Constructed with a lens structure of 7 elements in 6 groups, which often contributes to good optical quality.
  • The lens diameter of 8.3 cm and filter size of 7.7 cm are provided for clear compatibility with accessories.

👎 Cons

  • As a prime lens, it has a fixed focal length of 400mm, lacking the versatility of a zoom lens for different compositions.
  • The specific maximum aperture is not provided, making it difficult to assess its low-light performance or depth-of-field control.
  • The lens is specifically designed for Pentax 645 SLR cameras, limiting its compatibility with other camera systems.
  • We do not have information on the lens weight, which is an important consideration for a large telephoto lens regarding portability and handling.
  • No details are provided regarding image stabilization, which can be a critical feature for hand-holding a 400mm lens.

Frequently Asked Questions

This lens has a fixed focal length of 400mm, also listed as 40 cm, making it a telephoto prime lens.
ED stands for Extra-low Dispersion, which helps in reducing chromatic aberrations, while [IF] means Internal Focusing, where the lens length remains constant during focusing.
The lens structure consists of 7 elements arranged in 6 groups, a configuration that often contributes to optical quality.
The lens has a diameter of 8.3 cm and a filter size of 7.7 cm, important specifications for accessories.
The Pentax 26555 smc FA 645 400mm ED [IF] Lens is designed as a component for SLR cameras, specifically the Pentax 645 system.
This is a prime lens, indicated by its fixed focal length of 400mm, meaning it does not zoom.

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