This is a wide-angle lens that was a perfect match for the Z-1P during the film camera era. Its most distinctive feature is its bright F1.8 aperture, making it a predecessor to the performance-focused large lenses of today. Recently, I've only used it occasionally for astrophotography, relying on its brightness. When shooting during the day, I think it has a resolution that can compete with modern lenses when stopped down, but at its bright F-value, it feels somewhat weak. Its advantages are the benefits of brightness in night photography and the soft, dreamy rendering in close-up shots. Also, the color reproduction is quite cool-toned, typical of Sigma. I've included the lens condition and sample photos, so please take a look. The camera used for the sample photos is a K-5. The first three photos are taken at the widest aperture, and the fourth photo is the same scene as the third, but at F4.5. The last photo is a bit out of focus, but it's a shot of the stars. Instant purchase is welcome. Thank you. Size... Pentax K-mount