Nyquist spatial frequency
= Nyquist spatial frequency
{c}
{title2=$\nu_{\max}=1/(2p)$}
Samples spaced by pitch $p$ can distinguish spatial frequencies strictly below $1/(2p)$ cycles per unit length. Thus the shortest limiting wavelength is $2p$; exactly at the limit a sinusoid's phase can make all samples vanish. A practical <deformable mirror> has additional limits from actuator influence functions and finite pupil geometry.