When two lines intersect, the opposite (X) angles are equal. On parallel lines, alternate (Z) angles are equal. On parallel lines, corresponding (F) angles are equal. On parallel lines ...

When the Z system was in its infancy, not that long ago, I was quite surprised that the first trilogy of up-market S-line primes had an f/1.8 rather than f/1.4 aperture rating, namely the Nikon Z ...