Blind shutters
"At fast shutter speeds, the second curtain would set off before the first had completed its journey, meaning that a moving slit of light traversed the film. That was fine for naturally illuminated shots,"
The important constraint of the blind shutter was that it distorted moving objects. Effectively it was taking many slices of the picture at different times sequentially. A horizontal shot compressed or expanded an object moving horizontally across the view. In a vertical shot then any vertical movement was similarly affected. Whether it was noticeable depended on how fast the object was moving.
Biting the hand that feeds IT
