This is an explanation of the differences between HAL 220 B9 and B11.
The basic optical performance is the same, but there is a difference in the aperture.
The difference in aperture value
HAL 220 B9 has an aperture range of T2.9-T16
HAL 220 B11 has an aperture range of T2.9-T22
Sunstar Shapes (9-element and 11-element apertures compared)
HAL 220 B9 has a 9-element aperture
HAL 220 B11 has an 11-element aperture.
The difference in the number of aperture feathers appears as the difference in the Sunstar shapes.
