We have used the STEM optimum imaging method in which we employ an optimum magnification (scan size, D) for given electron probe size (δ). This can be written as D=420δ (Nyquist rate), when a micrograph is taken at 1024 scan lines [1], Over sampling (D<420δ) or under sampling (D>420δ) in biological scanning transmission electron microscopy may cause the following problems: (1) In the case of over sampling, an area of a specimen will be scanned too many times so that the effects of radiation damage will be increased; (2) when a micrograph is taken at under sampling conditions, we may be observing only part of a specimen in which electron probe scans with an open space between each scan line. In practice we try to obtain a micrograph with the optimum imaging conditions (D=420δ) followed by an optical reconstruction procedure using a low-pass spatial filter. Only spatial frequency information lower than <(2d)-1 produces the reconstructed image, where d is the spacing between scan lines. Figure 1 shows the filtering procedure in which a STEM micrograph of 30 Å-thick amorphous carbon film taken at D=3700 Å and δ = 8.8Å was used for the illustration. The corresponding optical diffraction pattern is shown in (b) where the location of the low-pass filter is indicated. Figure 1(c) shows the reconstructed image of (a) which consists of the spatial frequency of <(7.2Å)-1