• Material: Usually high-grade optical glass such as ED (Extra-low Dispersion), fluorite, or aspherical glass to reduce chromatic aberrations.
• Coatings: Multi-coated or nano-coated to reduce reflections, flare, and ghosting, improving contrast and color fidelity.
• Shape: Precision-curved elements (spherical or aspherical) that control how light passes through the lens.
• Durability: Scratch-resistant and sometimes weather-sealed for protection in tough environments.