Telephoto lens system of falconiform eyes

@article{Snyder1978TelephotoLS,
  title={Telephoto lens system of falconiform eyes},
  author={Allan W. Snyder and William H. Miller},
  journal={Nature},
  year={1978},
  volume={275},
  pages={127-129}
}
VISUAL ACUITY in falconiform birds has been shown to be higher than man. For instance, vultures with eyes similar in size to those of man have a grating detectability of about twice the spatial frequency of man1. This is consistent with measured image quality in an eagle eye similar in size to the human eye2. Recently a falcon (Falco sparverius) has been shown to have a grating detectability 2.6 greater than that of man3. Although the image quality of these falconiform eyes is at least twice as… 
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