Variability of QSOs serves not only as an independent search technique but also as another parameter to correlate with such properties as luminosity (in radio, optical, X-ray), redshift, spectral features, color, etc., so as to better understand AGNs. We present some preliminary results on a variability study of an essentially complete sample using 4 m prime focus plates of a 0.3 deg2 field at the North Galactic Pole (SA57). The faintness of our survey, B ≈ 23; the precision of the measurements (σ ≤ 0.05 mag); and the availability of redshifts for many of the candidates provide an opportunity to study QSO variability in regimes previously unexplored (c.f. Bonoli et al. 1979 or Hawkins 1986).