Zooming won't cause pixellation per se - although as Zion says it does depend on the scaler inside your display. However, because the scaler has to do more work to display a 4:3 letterboxed source, the image quality will not be as good as a 16:9 anamorphic disc.
Zooming won't cause pixellation per se - although as Zion says it does depend on the scaler inside your display. However, because the scaler has to do more work to display a 4:3 letterboxed source, the image quality will not be as good as a 16:9 anamorphic disc.