Figure 15.

Factors affecting visibility with the tilted MxP at the apex end and the base end of the shifted views as a function of prism rated power. Since the base end of the shifted view is near the critical angle of incidence, the farthest expanded field has the highest compression (minification), lowest transmittance, and lowest contrast. (A) Magnification factor (in log scale). Note that the reciprocal of magnification factor is compression factor. While the base end of the shifted view is compressed (magnification factor < 1), the apex end of the shifted view is actually magnified. (B) Transmittance. Transmittance of the shifted view in an MxP with 1:1 aperture ratio is about 25% at the base end of the shifted view, but it is about 45% at the apex end of the shifted view. (C) Contrast factor.¹⁷ Due to the reduced transmittance in the shifted view, the contrast is reduced more at the base end of the shifted view (~35% of the original contrast) than the apex end of the shifted view (~50% of the original contrast).