Used Sigma AF 20mm F1.8 (Nikon)

Item Details:

• Brand: Sigma
• Model: 20mm F1.8 EX DG Aspherical RF
• Mount Type: Nikon F
• Format: Full Frame (FX) and APS-C
• Focal Length: 20mm
• Maximum Aperture: f/1.8
• Minimum Aperture: f/22
• Lens Construction: 13 elements in 11 groups, including 2 aspherical elements
• Diaphragm Blades: 9
• Filter Size: 82mm
• Weight: 520g
• Dimensions: 88.6mm (Diameter) x 89.5mm (Length)

Key Features:

• Wide-Angle View: Provides a 94.5-degree angle of view on full-frame cameras, making it suitable for landscape, architectural, and astrophotography.
• Fast f/1.8 Aperture: Excellent for low-light conditions and creating a shallow depth of field.
• Internal Focus: The lens does not change length during focusing, and the front element does not rotate, making it easier to use filters.
• Build Quality: Robust construction typical of Sigma's EX series, designed to handle various shooting conditions.

Performance:

• Sharpness: Good center sharpness when stopped down to f/2.8 and beyond. The lens is softer wide open at f/1.8.
• Distortion: Minimal barrel distortion, which is well controlled for a wide-angle lens.
• Vignetting: Noticeable at f/1.8, reducing significantly by f/4.
• Chromatic Aberration: Some chromatic aberration is present, especially at wider apertures, but can be corrected in post-processing.
• Flare and Ghosting: The lens is prone to flare and ghosting, particularly when shooting into the light, despite the use of anti-reflective coatings.