Tamron SP 90mm f/2.5 Macro Autofocus Lens for Pentax K-Mount

Tamron SP 90mm f/2.5 Macro Autofocus Lens (Pentax K-Mount / Model 52B/152B)
The Tamron SP 90mm f/2.5 Macro Autofocus is a legendary, high-performance telephoto macro lens designed for Pentax K-mount SLR and DSLR cameras. Hailing from Tamron’s elite “Super Performance” (SP) lineup, this lens is revered by portrait photographers and macro specialists alike for its razor-sharp resolution, exceptional contrast, and beautiful, creamy background blur. Featuring an ultra-bright f/2.5 maximum aperture—rare for a macro lens—this optic pulls double duty as a world-class portrait lens and a precise close-up tool, delivering pristine medium-format-like image quality across the frame.

Dual-Purpose Performance: Ultra-Bright Portraiture & Macro Precision
Rare f/2.5 Maximum Aperture: Considerably faster than traditional f/2.8 or f/4 macro lenses, the f/2.5 opening offers superb light-gathering capability for low-light shooting and grants extensive control over depth of field.

Signature Portrait Rendering: At 90mm, this lens provides the ideal telephoto compression and perspective for portrait photography. Shot wide open, it yields a razor-thin plane of sharp focus while completely melting away backgrounds into smooth, dreamlike bokeh.

1:2 True Macro Reproduction: Captures intricate, fine-grained details natively at a 1:2 (half life-size) reproduction ratio. When paired with a dedicated Tamron SP 2x teleconverter or extension tube, it seamlessly steps up to a 1:1 life-size macro magnification without sacrificing its signature optical clarity.

Legacy Autofocus Integration & Advanced Optics
Pentax K-Mount Compatibility: Fully compatible with Pentax K-mount camera bodies. The lens utilizes the camera’s internal screw-drive motor to deliver reliable autofocus tracking, while featuring a dedicated, smooth manual focus ring for critical close-up adjustments.

Tamron SP Optical Architecture: Built to strict Super Performance standards using high-grade optical glass and advanced multi-coatings. The optical formula effectively suppresses chromatic aberrations, secondary color fringing, and geometric distortions, guaranteeing remarkable contrast and color fidelity even when shooting wide open.

Classic Mechanical Construction: Features a robust, high-durability barrel design built to withstand decades of heavy field use, ensuring steady optical alignment and smooth mechanical action.

Technical Specifications
Focal Length: 90mm (Approx. 135mm equivalent on APS-C sensors)

Aperture Range: f/2.5 to f/32

Lens Mount Type: Pentax K-Mount

Focus Control: Autofocus (Body Screw-Drive dependent) and Manual Focus

Filter Thread Diameter: 52mm

Minimum Focus Distance: Approx. 15.3″ (39 cm)

Macro Reproduction Ratio: 1:2 Natively (1:1 with optional extension adapters)

Optical Formula: 8 Elements in 6 Groups