Get Sigma 135mm f/1.8 DG HSM Art at B&H Photo.
This series looks at sharpness across the field, along with foreground and background color correction in out of focus areas.
Includes images up to full resolution from f/1.8 through f/13.
David C writes:
That shot of pescadero creek is amazing. please don’t tell me it was handheld
DIGLLOYD: it’s not possible to handhold an aperture series, and I would never evaluate sharpness handheld at 1/13 second.