the same DOF and the same amount of light - excellent
so essentially an f2.8 lens will not give extra quality at other aperture settings compared to other lenses 'just because it's an f2.8 lens', it merely allows you to take a shot at f2.8 albeit less DOF
fantastic !
thanks it just confirms in my mind I've no need to spend loads more on heavier more expensive f2.8/f4 lenses when I really want to be taking shots at at least f5.6 to get sufficient DOF on say a bird or animal; an f2.8 lens at f5.6 costing thousands isn't going to be letting in any more light than say a bigma at f5.6, assuming both the quality of the glass is the same it should result in the same quality/sharpness of picture at the same aperture and focal length
thanks
