Does every UV camera need a quartz lens to work properly?
A. No, it is not a requirement for near-UV imaging. Standard lens glass (BK7, for example) transmits plenty of light at 360nm, right in the middle of the near-UV band. Below about 330nm, standard lens glasses start to absorb UV as the wavelength gets shorter. By 280nm, there is virtually no transmission of a UV light signal through them. Most UV lenses are designed to work from 400nm down to 200nm, where quartz cuts off. We have found that if one wants to use a conventional color lens on a UV camera, it must have broadband AR coatings or else it will not have good transmission. Color lenses are not color corrected for UV light, and a reduction in image sharpness may be observed unless a narrowband source like an LEd array is used as illumination. Q.
