03-13-2012, 08:12 AM
Someone please correct Klaus as well as he consistently makes claims like: [url="http://www.opticallimits.com/nikon--nikkor-aps-c-lens-tests/705-sigma1770284os"]f/4.0-5.6 (full format equivalent, in terms of depth-of-field - not speed)[/url]. Or is speed different than light gathering?