On Apr 19, 2006, at 8:33 PM, Russell Kerstetter wrote:
so lenes that are optimized for digital in addition to being smaller are designed to have less CA?
No optical designer ever designed a lens to have more CA ... it's just that film and digital sensors constitute entirely different kinds of light sensitive recording mediums. Some lenses' light path is such that CA is exaggerated on the digital sensor, that's all.
A lens designed to work well on a digital sensor takes the sensors characteristics (sensitivity to incidence angle, hotspots that can arise from back-reflection, etc) into account in the design to reduce these things, including CA. In general, any lens that works well on digital sensors will also work well on film of the same format dimension because film is relatively insensitive to these kinds of things, but both medium respond well to lower CA, better resolution, better contrast, etc.
Godfrey
