Vision into the ultraviolet spectrum is thought to be the “norm” for tetrapods (e.g. amphibians, reptiles, birds), fish and insects. Even small mammals have shortwave sensitivities which stretch far deeper into the UV than human vision. Photography in the UV range is therefore essential for addressing many questions in visual ecology related to these species.
Ultraviolet photography presents a number of major difficulties:
- Camera sensors are typically only sensitive to light in the human-visible range. So cameras need modifying to become sensitive to UV. See full-spectrum cameras.
- Lenses designed for cameras typically do not transmit into the ultraviolet, and if they do they tend to have sever chromatic aberrations and focus shift. The options are to use expensive UV-VIS dedicated lenses, use exiting lenses and accept poor-quality UV images, or acquire second-hand lenses which happen to have excellent UV transmission. See UV lenses.
- Calibration is more tricky because the grey standards and colour charts used must extend into the UV range.