Zeiss Superspeed MK1 B-Speed Prime Lens Set T1.4
When you can’t afford the Mark 3 Superspeeds, the Zeiss Superspeed Mk1 (or B-Speeds as they are also known) are a great alternative. Optically there is almost no difference between all the Superspeeds. The main differences are mechanics of operation and the iris shape.
This set of Superspeeds is ready to shoot low-light and is the full set: 18mm, 25mm, 35mm, 50mm and 85mm. All the fronts are 80mm for easy matte-box use and the focus rings have gears. The mounts are Arri-PL.
Developed by Zeiss in 1975 following their work on low-light lenses for Nasa, and demand from Stanley Kubrick, these lenses were used on classic films such as Taxi Driver, and Full Metal Jacket. What is distinctive about them is the 9 blade Realeaux iris. When stopped down, the triangular iris was developed by Zeiss to allow for rays to come from the outside and inside parts of the lens to avoid focus shift with fast lenses. They also reduce streaking from bright points of light. However, the shape does give the bokeh a more distinctive look than a rounder iris.
However, most of the time people use Superspeeds because they want to shoot as wide open as possible, in which case the iris shape does not really factor into it. The Superspeeds are the lenses that will still give you a sharp image when shooting at low apertures, and complement digital cameras well.
The mechanical differences are that the rotation for focus is half turns, so the focus markings are close together.
There is a great guide to the history and optics of the superspeeds on the Cinematechnic site. Jeorge comments that these cut well with the later Superspeeds and there is no difference in sharpness.
Please note due to the replacement value of these lenses, you will need to be a recognised professional in order to hire.