The Sony 16-35mm f/4 ZA OSS delivers impressive optical performance, especially in the center of the frame. While some compromises exist at the edges, the lens overall performs well for its price and class.

Sharpness

• Center Sharpness: Excellent at all focal lengths, with peak performance around f/5.6. At f/4, the center remains sharp, ideal for low-light or shallow depth-of-field shots.
• Edge Sharpness: Some softness is noticeable at the edges, particularly at 16mm and f/4. Stopping down to f/5.6 or f/8 improves edge-to-edge sharpness significantly.
• Zoom Range Consistency: Performance remains consistent throughout the zoom range, with slightly better results at the wider end.

Color Rendering and Contrast

• Color Reproduction: Colors are vibrant and natural, with the Zeiss T* coatings enhancing saturation and reducing haze.
• Contrast: High contrast is maintained across the frame, even in challenging lighting conditions, contributing to punchy, vivid images.

Bokeh

• Background Blur: While not a primary focus for wide-angle lenses, the f/4 aperture can produce decent background separation for close-up subjects. The bokeh is smooth and pleasant, though not as creamy as telephoto or prime lenses.
• Out-of-Focus Highlights: Highlights are generally well-rounded but can exhibit some onion-ring artifacts due to aspherical elements.

Optical Aberrations

• Chromatic Aberration: Minimal thanks to the ED elements, though slight color fringing may appear in high-contrast areas at the edges.
• Distortion: Noticeable barrel distortion at 16mm and slight pincushion distortion at 35mm, both easily correctable in-camera or during post-processing.
• Flare and Ghosting: Excellent resistance to flare and ghosting, a result of Zeiss’s T* coating. This makes the lens reliable for shooting into bright light sources like the sun.
• Vignetting: Moderate vignetting is present at f/4, particularly at 16mm. Stopping down to f/5.6 significantly reduces this effect.