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Pentax SMC 135mm F2.5 Camera Lens Telephoto Portrait Lens (K-Mount) - $150 (Austin)
condition:
good
make / manufacturer:
Pentax
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Because it’s f/2.5, this lens is “fast” — good for portraits, low-light, and shallow depth-of-field.
Its 135 mm focal length is classic for portraiture or short telephoto work (compression of background, flattering perspective).
No electronics — so no communication with modern cameras; aperture and focus are set fully manually.
Solid metal build, compact-ish for a telephoto, and relatively lightweight for a 135 mm prime.
Here are the exact mount & specs for SMC Pentax 135mm F2.5 — i.e. the “SMC Pentax 135 mm f/2.5” lens.
Mount type
The lens uses the Pentax K mount (PK / K-mount).
It is a manual-focus lens with no electronic contacts.
Designed originally for 35 mm film SLRs and is fully compatible with full-frame (35 mm) and 35-mm–equivalent on APS-C (with crop).
🛠️ Lens Specifications
Attribute Specification
Focal Length 135 mm
Maximum Aperture f/2.5
Minimum Aperture f/32
Optical Construction 6 elements in 6 groups
Diaphragm Blades 8 blades
Minimum Focusing Distance 1.5 m (≈ 5 ft)
Maximum Magnification ~ 0.11×
Filter Thread 58 mm
Physical Size (Diameter × Length) ≈ 68 mm × 86 mm
Weight ≈ 500 g (about 495–500 g depending on source)
Focus Type Manual focus only (no autofocus)
Coverage / Format Full-frame 35 mm / 35 mm film; works on APS-C with crop factor