Pentax's vintage standard zoom — the compact 40-80mm f/2.8-4 for K-mount film cameras.
The Pentax SMC 40-80mm f/2.8-4 is a vintage standard zoom for the Pentax K mount, covering a useful range from normal to moderate telephoto. The f/2.8 starting aperture is fast for a vintage zoom, providing good viewfinder brightness and depth of field control at the wide end. The SMC multi-coating ensures good contrast and flare resistance.
Optical performance is decent for the era. Sharpness is good in the centre throughout the range. The fast f/2.8 starting aperture is a notable advantage over many vintage standard zooms that start at f/3.5 or slower. The SMC coatings maintain good contrast. The zoom range is modest but practical, covering the most commonly used focal lengths.
Pentax K mount, manual focus. Filter thread is 49mm — compact. Weight is approximately 285 grams — lightweight for a variable-aperture standard zoom. Build quality is solid metal construction with smooth zoom and focus rings. Compatible with all Pentax K-mount bodies. The SMC coating quality is excellent across the production run.
Available on the used market at low prices. Check for smooth zoom and focus operation. The f/2.8 starting aperture makes it more useful than many vintage standard zooms. A decent compact standard zoom for Pentax film shooters. Modern Pentax zooms are dramatically better but this remains a functional vintage option.