A number of the South East tribes (Southern Zimbabwe down) use the rawhide shield, but the shape and size differ from tribe to tribe and even between clans in the same tribe.
This is of course, as it is today and no doubt there has been some adaptation over time (meaning my observations are current day).
The typical Zulu battle shield is about 600mm at its widest point and anything from 1400mm to 1600mm tip to tip. The lower point generally is just below the knee and the upper point level with the top of the head, but even here there is some variation.
The Tonga and Matibili (the latter are an off shoot of the Shaka day Zulu) also use this style, shape and size of shield.
The SiSwati and Shangaan shields tend to be shorter and even some times slightly wider, 600mm to 700mm wide and not much longer than about 1100mm to1200mm tip to tip
The Xhosa shield on the other hand is generally much smaller circa 400mm wide and only about 900mm to 1100mm tip to tip.
The Soto and Shuna traditionally favour no shield and tend to very effectively use a stout stick for parrying and deflecting.
Just to confuse this a little more, the shield in the photo looks like something between the typical Zulu Shield and the current day SiSwati shield.