Shooting With The Si-K; Lens Selection - Silicon Imaging SI-2K User Manual

Shooting with the SI-2K

Lens Selection

The lenses used with the Silicon Imaging cameras will have tremendous effect
on the final quality of the image. No amount of post processing can repair con-
tent shot with poor optics.
C-Mount
The requirements for a C-mount lens to work:
1) The lens must be C-mount and not CS-mount (same thread, different
back focal length, the CS-mount is used mostly for surveillance)
2) The lens must have an image circle of at least 2/3" (the real sensor size is
10.24 mm x 5.76 mm or a 11.75 mm diagonal) or vignetting will occur.
3) The lens should not be designed for 3 chip cameras. (these lenses have
differing path lengths for each color and the lens corrects for that)
If the lens differs from 2/3", there is a multiplying factor. For Super-16 lenses,
the multiplier is about 1.1, for 35 mm lenses, it is about 2.5.
PL-Mount
An Arri PL-mount can optionally be used. Super 16 lenses are an ideal match
in optical circle size and have minimal magnification. 35 mm lenses will work,
but will have a 2.4x magnification factor for 2K images.
B4-Mount
Because the SI-2K is a single chip camera, from an optical point of view, it
behaves more like a film camera than typical 3 chip cameras. The B4 adapter
includes optics to correct for the color path length that is inherent in 3 chip
digital camera systems. B4 lenses designed for 2/3" sensors are an excellent
match.
Note: Please use B4 Lenses on the B4 Mount only for HD Resolutions to
prevent cushioning-
Other Mounts
Other lens mounts are available (see the pricelist on-line). Keep in mind that
35mm lenses will include a magnification factor.
ShootingwiththeSI-2K
SI 2K Manual