I wrote: >Hence, lenses with the most circular aperture holes (many aperture blades) >will keep the round shape the longest.
Which means that out of focus areas will be softer and less "edgy" than lenses with few aperture blades. The "drawback" (dependent on point of view) is that doughnut shapes will "last longer" as the highlights are rounder. In fact even angular highlights with aperture hole shapes show the doughnut effect but it isn't really noticable because most people see only the shape. If one scrutenize such an image it will show that the rim of the aperture shaped high-light is slightly brighter than the middle section. > To avoid it is basically to avoid highlights at a certain distance from the > focusing plane. More precisely, one should avoid a certain begree of defocusing which can be controlled by focusing or aperture selection. On the other hand, most great photographer don't give a damned about this proven by the countless of award winning photos (again see one of the National Geographic books on photography) showing this effect. Nobody has complained yet! P�l
