1.  Lens Comparisons Stefano Prezioso

2. Lens Image Characteristics  Resolution (Sharpness)  Distortion  Vignette (Light Falloff)  Chromatic Aberration

3. Resolution  How “sharp” the lens is  Contrast  Resolving Power of Detail  Measured and Quantified in MTF Charts  Lenses “Out Resolve” the Sensor

4. Distortion  Three types  Pincushion  Barrel  Mustache  Most noticeable at edges/corners  Usually Correctable

5. Vignette  Amount of Light Fall Off in Lens  Increases as Distance from Center Increases  Measured in Exposure Value (EV) Stops  Correctable in Post Processing

6. Chromatic Aberration  Different Colors Converge at Different Points  Good Lenses are Corrected  Correctable in Post-Processing

7. 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

8. 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

9. 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

10. Pricing Overview Nikkor AF-S 14-24 f/2.8 G ED$1549 Nikkor AF 14mm f/2.8 D ED$1390 Nikkor AF-S DX 10-24mm f/3.5-4.5G ED$780 Nikkor AF-S 12-24mm f/4G IF-ED DX$900 Sigma EX 10-20mm f/3.5 EX DC HSM$649 Sigma AF 10-20mm f/4-5.6 DC EX HSM$479 Sigma AF 12-24mm f/4.5-5.6 EX HSM DG$859 Tamron SP AF 10-24mm F/3.5-4.5 Di II LD Aspherical IF $474 Tokina AF 12-24mm f/4 AT-X Pro DX$499 Samyang 14 mm f/2.8 IF ED MC Aspherical$426

11. Resolution at f/8 14mm LensCenter f/8Edge f/8Extreme f/8 Nikkor AF-S 14-24 f/2.8 G ED @ f/42212.52143.52051.5 Nikkor AF 14mm f/2.8 D ED217619811750.5 Nikkor AF-S DX 10-24mm f/3.5-4.5G ED209920381863 Nikkor AF-S 12-24mm f/4G IF-ED DX @ 18mm21131898.51839.5 Sigma EX 10-20mm f/3.5 EX DC HSM @ 15mm214420201861 Sigma AF 10-20mm f/4-5.6 DC EX HSM @ f/5.6218119931780 Sigma AF 12-24mm f/4.5-5.6 EX HSM DG @ 17mm 20372000.5No Data Tamron SP AF 10-24mm F/3.5-4.5 Di II LD Aspherical IF 210018841479 Tokina AF 12-24mm f/4 AT-X Pro DX @ f/5.6 18mm 2104.51890.51756 Samyang 14 mm f/2.8 IF ED MC AsphericalAwesomeSuperbGreat

12. 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

13. Distortion Results Nikkor AF-S DX 10-24mm f/3.5- 4.5G ED Very Good from 14mm-18mm Nikkor AF-S 14-24 f/2.8 G ED14mm: Very Slight 18mm+: Exceptional Sigma EX 10-20mm f/3.5 EX DC HSM 15mm: Almost Perfect Sigma AF 12-24mm f/4.5-5.6 EX HSM DG Very Good throughout Samyang 14 mm f/2.8 IF ED MC Aspherical Absolutely Awful

15. Chromatic Aberration Results Nikkor AF-S DX 10-24mm f/3.5- 4.5G ED Moderate Nikkor AF-S 14-24 f/2.8 G EDGood Sigma EX 10-20mm f/3.5 EX DC HSM Moderate Sigma AF 12-24mm f/4.5-5.6 EX HSM DG Terrible Samyang 14 mm f/2.8 IF ED MC Aspherical Stunning

16. Vignetting Results Nikkor AF-S DX 10-24mm f/3.5- 4.5G ED 0.51 EV Nikkor AF-S 14-24 f/2.8 G ED0.2 EV Sigma EX 10-20mm f/3.5 EX DC HSM 0.45 EV Samyang 14 mm f/2.8 IF ED MC Aspherical 1.36 EV

17. 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?

18. 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

19. 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