PAGE UNDER REVIEW AND NOT FINAL
ALPA PRODUCT TYPE
Legacy Product

ALPA Apo Switar 5.6/36 mm

__

Legacy Product

Schneider / ALPA Apo Switar 5.6/36 mm

What a diva and what a great lens. Inverse curvature of field and only a handful were able to set the calibration correctly. For many architecture photographer this was and sometimes still is their "bread and butter" lens. Stellar with digital back and sensors of 9 down to 6.8 micron pixel size, demanding to control below this lens was one of the cornerstones of the ALPA lens arsenal.

About Center Filters

When working with ultra-wide-angle lenses, the falloff of illumination towards the corners is sometimes disturbing. For this reason, concentrically graduated Center Filters have been designed to compensate for this vignetting. These filters have transparency that increases gradually from the center to the edges of the filter, where it reaches full transparency. The transmission is independent of the wavelength of the visible spectrum.

To avoid overexposure and consider the film emulsions' exposure latitude in the analog area, the optic manufacturers do not fully compensate for the lens's vignetting. This working hypothesis was adapted to the digital world.  Specification 1.5, 2.5, etc. indicates the extension factor for the exposure.

As Center Filters must be on par with the lens quality, they are manufactured at the same level as optics. The price reflects this level of complexity.

The brightness drop / vignetting of digital backs can also be compensated by a digital correction function. This process is achieved by image analysis or, in the more complex and more accurate case, by a correction image with digital analysis. The latter variant (LCC Lens Cast Calibration, Scene Calibration) analyzes the edge falloff and color shifts utilizing a separate neutral image taken with an opaque white disc.

Since this process has to be offset against the image(s), the correction image is taken with the same aperture and shift adjustment as the original. This correction benefits from the existing dynamic range. For an optimal result, it may therefore be necessary to combine both techniques.

ALPA Product ID - PID
Lens designation was AAS 36
Price Estimate in CHF

Technical Details

No items found.