The Rodenstock 150mm f/5.6 Apo-Sironar-S Lens is a 4x5 format lens for universal use which 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 150mm Sironar-S is a whopping 75°, permitting generous shifts of at least 45mm in the 4x5 format. This allows more control over the large format image, and less limits upon the creative capacity of the photographer. Despite the broad coverage, it is still a small lens with a compact 51mm rear barrel, permitting its use upon the smallest 4x5 field cameras. In most cases, this lens can fit inside a field camera when the camera is folded away. 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/11 with another "normal" 6-element/4-group lens, the Apo-Sironar-S will still impress. Indeed, f/11 is within its recommended shooting aperture range.