Tamron's Adaptall-era standard zoom for Pentax — the SP 24-135mm with versatile range.
The Tamron SP 24-135mm f/3.5-5.6 AD Aspherical IF for Pentax K mount is a versatile standard zoom covering a useful 24-135mm range. The SP designation indicates Tamron's premium tier. The AD and aspherical elements provide optical correction. IF internal focusing prevents barrel rotation. A practical walk-around zoom with wider-than-usual coverage.
Optical performance is decent. The 24-135mm range is more versatile than standard 28-80mm zooms. Centre sharpness is acceptable. The SP build quality is solid. The IF design is practical for filter use. No image stabilisation — benefits from Pentax in-body SR on digital bodies. The aspherical element helps at wider focal lengths.
Pentax K mount. Filter thread is 72mm. Weight is approximately 475 grams — moderate. Build quality is solid SP tier. Benefits from Pentax body SR stabilisation. The screw-drive AF uses the body motor. The 24-135mm range covers most everyday situations without the extreme compromises of 28-300mm superzooms.
Very affordable on the used market. Check AF and zoom. A practical walk-around zoom with better range than standard zooms. The 24mm wide end is more useful than 28mm. The body SR on Pentax DSLRs compensates for the lack of lens IS. Adequate for everyday use at very low cost.