The Light Enviroment Water strongly attenuates long wavelenghts of light & UV (see video below, Fig 1). Depending on the visibility and the type of disolved matter in the water, the ambient light quickly turns into a dim blue (clear
UV Lenses
Photography lenses are typically designed for operating in the human-visible ~420-680nm range. Within this range the lenses have good transmission, and control for chromatic aberrations (e.g. the red, green and blue channels are all in focus). UV photography ideally requires
UV-VIS filters
UV photography requires a UV-pass filter (for UV-only photography) and a visible-spectrum-pass filter (also called a UV/IR cut or blocking filter). Photographs are taken with each of these filters using a full-spectrum camera. Available filters (empirical imaging has no affiliation
Full Spectrum Camera
Camera sensors are developed for recreating images in the human-visible range, however the sensors themselves (CMOS or CCD) are actually typically sensitive down into the relevant UVA range for modelling animal vision (typically about 320nm), and the same sensors are
Scale Bar
Pattern analysis and acuity control require all images be scaled to a uniform number of pixels per unit length – a number that will vary with every study. Photographing different samples from slightly different distances can be controlled for with
Grey Standard
At least one grey standard of known reflectance is required in each photograph (or in a separate photograph taken under exactly the same conditions and with identical camera settings). Greyness and Diffuseness The standards used should ideally have equal levels
Essential Equipment
For making objective measurements of reflectance (the amount of light reflected by an object relative to a reflectance standard), colour, and pattern all you need is a digital camera that can produce RAW images (or one you have made a
Ultraviolet Photography
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
Light Source
Photography is entirely dependant on light and the way it bounces off or through objects, so is an important consideration before starting data collection. In an ideal world, all photographs that you want to compare should be taken under uniform