The Rodenstock 210mm f/5.6 Apo-Sironar-S Lens is a slightly long lens for either the 4x5 or 5x7 formats. Designed for universal use, it has been modified to provide the highest image reproduction quality. Like the Apo-Sironar-N, its applications are practically limitless. Its special strengths can be seen when complex, fine structures in the adjustment range have to be reproduced.
The angle of coverage of the 210mm Sironar-S is a whopping 75deg., permitting very generous shifts of at least 90mm in the 4x5 format and 61mm in the 5x7 format. This allows more control over the large format image and less limits upon the creative capacity of the photographer. It is particularly useful when photographing architecture from the ground level.
Today's modern fully-multicoated lenses for large format film cameras available from the 'big four' are all so good that for the most part they're practically interchangeable. Perhaps it has been more important to consider the lens dimensions in relation to your camera's limits, or perhaps collect lenses based on a shared filter size. But in the tried and true 6-element, 4-group standard lens formula, the Apo-Sironar-S stands head & shoulders above the rest thanks to its ED glass.
This lens stuns at ideal apertures like any of the modern 6-element/4-group lenses will, but it is at the apertures which are far from ideal in the world of large format where the Apo-Sironar-S justifies its superior performance claims. While you might be disappointed with a skillfully-crafted effort at f/16 with another 210mm 6-element/4-group lens, the 210mm Apo-Sironar-S will still impress. Indeed, f/16 is within its recommended shooting aperture range.