Sony DXC-990 Manual page 49

Q.15: Can lenses other than the optional lenses be used for
DXC-390/390P?
There are limitations to the type of C mount lenses used with the DXC-390/390P.
A:
The lens must not project more than 4.3 mm (3/16 inches) from the lens mount
surface. Even if lenses meet this requirement, color aberration may appear because
most C mount lenses on the market are designed for one CCD, not for 3 CCD, cameras.
In addition, lenses other than the optional Sony VCL-610WEA or VCL-614WEA cannot
control zoom, focus and iris functions by the RM-C950 remote control unit.
Distance from lens mount surface must not be more than 4.3 mm
DXC-990/990P, DXC-390/390P Sales Manual – 47