Zebra pattern8/16/2023 ![]() You can also use faces and skin tones, but there is a very wide range of variation in the brightness of faces. Generally a little bit brighter than a proper 90% white card, but any error this introduces will be very small, so white paper isn’t such a terrible compromise. As a “get out of jail” alternative a piece of paper isn’t a terrible option. However, I’m also well aware that there may be times when you don’t have access to a proper white or grey card. There are ridged charts from companies such as DSC Labs or X-Rite as well as handy, folding, pop-up charts from Lastolite. It needs to be a reasonable size as it’s much easier to measure the brightness of a large white/grey card than a tiny patch on a chip chart or similar. I strongly urge anyone that shoots with S-Log3 regularly to invest in a good, reasonably large, good quality white and grey card. But there are plenty of other cards on the market to choose from. My favourite is actually the back of a DSC labs “One Shot” chart as this has both middle grey and 90% white side by side. The best reference you can get will be a proper 90% reflectivity white card or an 18% reflectivity “middle grey” card. This research provides new evidence for the theory that zebras evolved dichromatic striped coats to evade biting flies and has considerable implications for the horse industry.Any exposure measurement or assessment requires some kind of reference. Therefore, it is unsurprising that zebras utilise both behavioural defences and morphological striping to avoid horse flies. In Africa where zebras are native, horse flies carry dangerous debilitating diseases such as trypanosomiasis and African horse sickness which cause wasting and often death. Consequently, any horse flies that did successfully land on zebras spent less time there compared to those landing on horses, with few staying long enough to probe for a blood meal. ![]() Zebras exhibited preventative behaviour, such as running away and tail swishing at a far higher rate than horses. The research also directly observed zebra and horse behaviour in response to biting flies. Horse flies are a widespread problem for domestic animals so mitigating techniques, such as the development of anti-fly wear designed to resemble zebra stripes, may, from this research, be an interesting outcome for animal health and wellbeing. Consequently, far fewer successful landings were experienced by zebras compared to horses." Professor Tim Caro, Honorary Research Fellow from the University of Bristol's School of Biological Sciences, said: "Horse flies just seem to fly over zebra stripes or bump into them, but this didn't happen with horses. However, video analyses revealed differences in approach speed, with horse flies failing to slow down on approach to zebras, which is essential for a successful landing. Their new study has shown that stripes don't deter horse flies from a distance, with both zebras and domestic horses experiencing the same rate of circling from the flies. Martin How and colleagues have been investigating the behaviours of tabanid horse flies around captive zebras and domestic horses at a livery in North Somerset, using video analysis techniques. Now, researchers from the University of Bristol and UC Davis, California, have added evidence to the theory that the primary purpose of zebras' stripes is for avoiding blood-sucking parasites. Many theories have been proposed, including avoiding predators, better heat regulation and a social function, yet there is still no agreement between scientists. ![]() The evolution of the zebra's two-tone coat has intrigued scientists for over 150 years.
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