Pentax SMC Pentax-A 28-135mm f/4 - Pentax KA Mount

The SMC Pentax-A 28-135mm f/4 is a versatile, constant-aperture zoom lens featuring the Pentax KA mount, allowing for aperture control via the camera body. Known for its substantial build quality and professional-grade optical performance for its era, it covers a broad focal range from wide-angle to portrait telephoto. It is particularly valued for maintaining a constant f/4 maximum aperture throughout the zoom range. Due to its size and weight, this model can be prone to zoom creep; ensure the barrel remains secure when tilted. The lens features a complex internal construction, so check for internal dust or micro-haze. SDS checks the electronic contacts on the mount to ensure correct communication with 'A' series and digital bodies, alongside testing the smoothness of the two-touch zoom and focus rings.