The Sigma 50mm f/1.4 is shown on both the Sony Alpha 900 (this shot) and the Nikon D3X (next shot) wide open. The performance will look worse than the regular standard lenses, but this is not a true reflection of the quality of the Sigma 50mm - it suffers most when close focused, and at the edges at full aperture. For distant work the centre is extremely sharp even at f/1.4, needing no stopping down, unlike both the old Minolta and new Nikon.