The following tables list the optical characteristics of KCWI. In some instances (denoted by *) predicted values are listed in lieu of actual measurements.
| Location | Left Nasmyth platform, Keck II; removable from focus |
| Bandpass (blue channel) | 350 to 560 nm (acceptable performance to 700 nm) |
| Field of View | 20 arcsec x (8.3, 16.5, or 33) arcsec selectable |
| Telescope Plate Scale | 1.375 arcsec/pixel |
| Detector Plate Scale | 0.15 arcsec/pixel |
| IFU Pupil Array Radius | 225 mm |
| IFU Slicer Radius | 5200 mm |
| Aberration Correction | Cylindrical fold mirror |
| Slit Height | 14.5 mm |
| Slit Width | 0.25, 0.5, 1 mm selectable |
| Beam Size | 150 mm |
| Collimator Focal Length | 2160 mm |
| Camera Focal Length | 305 mm |
| Gratings | VPH, 250 x 350 mm, selectable |
| Blue Detector | e2v 4kx4k, 15 microns pixel, thin, AR-coated CCD |
| Image Resolution | ~ 10 microns RMS (seeing-limited) |