Samyang's ultra-wide for Nikon DX — the 10mm f/2.8 for landscape and astrophotography.
The Samyang 10mm f/2.8 ED AS NCS CS is an ultra-wide manual-focus prime from Samyang for APS-C Nikon DSLR cameras, providing a 15mm full-frame equivalent field of view. ED (extra-low dispersion) glass, AS (aspherical) elements, NCS (Nano Crystal coating), and CS (Crop Sensor/APS-C) specifications are all indicated in the designation.
The lens delivers 10mm (15mm equivalent on APS-C) at f/2.8 maximum aperture with ED and aspherical optical correction, NCS Nano Crystal coating for flare reduction, CS APS-C-only image circle, Nikon F-mount, and fully manual focus and aperture.
The combination of ED, aspherical, and NCS coating represents Samyang's top optical specification applied to an APS-C ultra-wide. The f/2.8 at 10mm provides useful light gathering for astrophotography and interior photography. The NCS coating specifically targets the strong flare susceptibility of ultra-wide lenses.
Inspect NCS coating condition for cleanliness and integrity. Test aperture ring and focus ring smoothness. Verify CS APS-C image circle with no vignetting on the intended Nikon APS-C body. Check corner sharpness at f/2.8.