Lens Choice

The selection of a lens for Splicer is directly informed by the characteristics of the installed sensor. Both the pixel pitch and the physical line length of the sensor must be considered to ensure optimal image quality and functional performance.

Given the Piranha 2 Line Scan CCD sensor features an active line length of approximately 58 mm, it is essential to select a lens with an image circle exceeding this length. A larger image circle allows for lateral or vertical shifts without introducing vignetting. Failure to meet this criterion may result in partial sensor coverage and degraded image quality.

Additionally, lens selection must take into account the mechanical constraints of the focus axis V. The V axis provides a minimum extension of 53 mm and a maximum of 275 mm. These limits define the practical focal length range of usable lenses.

The following standard optical relationships from large format photography apply:
- At infinity focus, the lens-to-sensor distance approximates the lens's focal length.
- At 1:1 magnification (image size equals object size), the lens-to-sensor distance equals twice the focal length.

Based on these parameters, lenses with focal lengths of approximately 60 mm or greater can achieve focus at infinity within the V axis range. For 1:1 reproduction, lenses up to around 135 mm focal length may be used. Longer lenses or greater extensions may be accommodated with the addition of extension tubes mounted in front of the lens board, although this will require recalibration of the autofocus system.

Lenses designed for medium format enlargers typically provide sufficient image circle coverage and optical resolution for line-scan applications. These lenses are readily available on the secondary market and represent a cost-effective solution.

A widely used lens with Splicer is the Schneider Kreuznach Componon-S 80mm f/4 (V38 mount). Originally developed for line scan applications, this lens features high sharpness across the field and includes a red alignment dot indicating the optimal orientation for peak resolution. The specified image circle is 80 mm, making it suitable for use with the 58 mm sensor line length.