200 likes | 341 Vues
Lens Comparisons. Stefano Prezioso. Lens Image Characteristics. Resolution (Sharpness) Distortion Vignette (Light Falloff) Chromatic Aberration. Resolution. How “sharp” the lens is Contrast Resolving Power of Detail Measured and Quantified in MTF Charts Lenses “Out Resolve” the Sensor.
E N D
Lens Comparisons Stefano Prezioso
Lens Image Characteristics • Resolution (Sharpness) • Distortion • Vignette (Light Falloff) • Chromatic Aberration
Resolution • How “sharp” the lens is • Contrast • Resolving Power of Detail • Measured and Quantified in MTF Charts • Lenses “Out Resolve” the Sensor
Distortion • Three types • Pincushion • Barrel • Mustache • Most noticeable at edges/corners • Usually Correctable
Vignette • Amount of Light Fall Off in Lens • Increases as Distance from Center Increases • Measured in Exposure Value (EV) Stops • Correctable in Post Processing
Chromatic Aberration • Different Colors Converge at Different Points • Good Lenses are Corrected • Correctable in Post-Processing
Nikon Brand Lens Candidates • Nikkor AF-S 14-24 f/2.8 G ED • Nikkor AF 14mm f/2.8 D ED • Nikkor AF-S DX 10-24mm f/3.5-4.5G ED • Nikkor AF-S 12-24mm f/4G IF-ED DX
Sigma Brand Lens Candidates • Sigma EX 10-20mm f/3.5 EX DC HSM • Sigma AF 10-20mm f/4-5.6 DC EX HSM • Sigma AF 12-24mm f/4.5-5.6 EX HSM DG
Tamron/Tokina/Samyung Lens Candidates • Tamron SP AF 10-24mm F/3.5-4.5 Di II LD Aspherical IF • Tokina AF 12-24mm f/4 AT-X Pro DX • Samyang 14 mm f/2.8 IF ED MC Aspherical
Bad Resolution Results • Nikkor AF 14mm f/2.8 D ED • Nikkor AF-S 12-24mm f/4G IF-ED DX • Sigma AF 10-20mm f/4-5.6 DC EX HSM • Tamron SP AF 10-24mm F/3.5-4.5 Di II LD Aspherical IF • Tokina AF 12-24mm f/4 AT-X Pro DX
DxO Optics Pro 6 • Automatically corrects… everything. • Calibrated to specific camera and lens set up • Compatible with only certain lens/camera combinations • $169 for standard edition. EDU discount?
Final Picks • Sigma 10mm-20mm f/3.5 • Distortion free from 14mm-20mm • Sharp • Decent CA and Vignetting Characteristics • Samyang 14mm f/2.8 • Super Sharp • Perfect CA Characteristics • Bad Distortion and Vignetting
Surprise Lens • Sigma 14mm f/3.5 • Older Lens (Replaced by f/2.8 version) • No Profiles for Corrections (To my knowledge) • Sharp, Good Distortion Characteristics • Long Term Loan… Free