Schneider-Kreuznach — 150mm f/5.6 apochromatic plasmat, standard lens for 4x5 view cameras, Copal 0
The Apo-Symmar 150mm f/5.6 is the apochromatic successor to Schneider-Kreuznach's Symmar-S, introduced around 1990 and serving as the standard lens on 4x5 inch view cameras. It is a distinct product line from both the earlier convertible Symmar and the Symmar-S, and later from the Apo-Symmar L that replaced it.
Construction is a six-element, four-group symmetrical plasmat with apochromatic correction and multicoating, supplied in a Copal 0 shutter. Image circle is approximately 220mm at f/22, giving full 4x5 coverage with generous room for rise, fall and shift.
The apochromatic correction is the point of difference: secondary spectrum is controlled well enough that colour fringing stays negligible at the edges of the field, which matters for architectural work and for colour transparency. Sharpness peaks around f/16 to f/22 as with the rest of the family.
These are plentiful on the UK used market and represent good value now that digital capture has softened demand. Check the shutter fires accurately at slow speeds, inspect the elements at an angle for separation or cleaning marks, and confirm the aperture scale matches the correct cell pairing.