This lens has the same problem as any lens-system with a central obstruction; the contrast for medium-scale detail is poor, due to diffraction effects.
Image quality is generally specified using a concept called Modulation Transfer Function (MTF). It is like a frequency response for lenses except the frequency is spatial in cycles per mm rather than Hertz.
Lenses with a central obstruction can have comparable MTF with respect to unobstructed lenses of the same speed, at spatial frequencies near the limit of resolution. However, you try very hard not to use a lens that way because the performance is poor. At the more important, intermediate spatial frequencies, an unobstructed lens has much better performance.
Astronomers have picked up on this idea. They like to use reflective lenses with a central obstruction for viewing stars where resolution limit is the only thing that counts and the perfect colour correction provides an advantage. However, unobstructed refractors are better for planets where you have a distributed image.
It is possible to make reflective telescopes without a central obstruction but the technology is still a little expensive. I expect, one day, they will displace refractors.
Aliasing is another issue using a centrally-obstructed lens with a pixellated image sensor like a CCD or CMOS device. Spatial frequencies above the Nyquist limit (2 pixels per cycle) generate garbage within the pass-band of the detector. A lens of this type concentrates its performance in the worst frequency range for the detector.
There are lots of promising approaches for cheap, compact lenses for cell-phone cameras but I doubt this lens is one of them.
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This lens has the same problem as any lens-system with a central obstruction; the contrast for medium-scale detail is poor, due to diffraction effects.
Image quality is generally specified using a concept called Modulation Transfer Function (MTF). It is like a frequency response for lenses except the frequency is spatial in cycles per mm rather than Hertz.
Lenses with a central obstruction can have comparable MTF with respect to unobstructed lenses of the same speed, at spatial frequencies near the limit of resolution. However, you try very hard not to use a lens that way because the performance is poor. At the more important, intermediate spatial frequencies, an unobstructed lens has much better performance.
Astronomers have picked up on this idea. They like to use reflective lenses with a central obstruction for viewing stars where resolution limit is the only thing that counts and the perfect colour correction provides an advantage. However, unobstructed refractors are better for planets where you have a distributed image.
It is possible to make reflective telescopes without a central obstruction but the technology is still a little expensive. I expect, one day, they will displace refractors.
Aliasing is another issue using a centrally-obstructed lens with a pixellated image sensor like a CCD or CMOS device. Spatial frequencies above the Nyquist limit (2 pixels per cycle) generate garbage within the pass-band of the detector. A lens of this type concentrates its performance in the worst frequency range for the detector.
There are lots of promising approaches for cheap, compact lenses for cell-phone cameras but I doubt this lens is one of them.