Lens Tests: EF 28mm f1.8 USM Overview

The Holding Tank

Hardware

Lens Tests

| EF 28mm f1.8 USM | EF 50mm f1.4 USM | EF 100mm f2.8 Macro USM |

| EF 180mm f3.5L Macro | EF 180mm f3.5L Macro + EF 1.4X II | EF 180mm f3.5L Macro + EF 2X II |

EF 28mm f1.8 USM

| As Shot | CA Corrected | As Shot vs Corrected |

The EF 28mm f1.8 USM has a reputation for a sharp centre but soft edges and corners with high levels of chromatic aberration even on crop cameras. So these measurements are presented As Shot and exactly the same exposure corrected for CA in Adobe RAW. A summary comparison of the two is also given.

The CA correction applied was derived by quick visual examination and is shown in the below plot along with 2nd order curve fits.

fstop	fit red/cyan	fit blue/yellow
1.8	-30.3	-16.8
2	-30.4	-16.8
2.8	-30.7	-17.1
4	-31.0	-17.6
5.6	-31.5	-18.1
8	-32.2	-18.8
11	-33.0	-19.5
16	-34.0	-20.4
22	-34.9	-20.9

These values were derived for a subject (the test target) at a relatively shot distance however test shots in the field suggest a similar value. Probably a substantial correction at any f-stop and distance will be obtained with -30 red/cyan. After some iteration the fit curve was produced giving a residual APS-C corner CA of around 0.5 pixel. ARC Correction XMP files.

The comparative test shows a significant improvement in the edge and corner sharpness after CA correction (fit curve) above f2.8.

Peak centre sharpness occurs between f2.8 and f5.6. Peak corner sharpness occures at f8.

The following 100% crops show a real life case, all have been given standard capture sharpening of 0.7, 0, 300% USM edge masked and blended with a 65% luminosity.

The full frame @ f2