So, it's been a week since the majority of the UK were blessed with a sky full of aurora borealis... except those of us who were fast asleep!
The most common question I've been asked (apart from whether I saw them!) was why the colours of the Northern Lights were much more visible through a phone camera than with the naked eye.
Let's dig into the anatomy of how our eyes work, and process light, to better understand why our phone cameras have the upper hand...
The human eye has two different types of receptor cells at the back of the eye (rods and cones) which process the light that enters. Rod cells are highly sensitive to light and function in night vision, whereas cone cells are capable of detecting a wide spectrum of light photons and are responsible for colour vision.
The receptors that process colour, the cones, do not work well in dim light conditions. The rods are the receptors which work well in low light conditions, but these process light in grey scale. This is why the Northern Lights were mostly seen as white streaks across the sky.
For very strong displays it is possible to see some colour, but it will never be as bright or vibrant as the image your phone camera achieves. As our eyes simply do not have the ability to see bright colours when it's dark.
The way these cells are organised at the back of the eye also plays a part. Cone cells are concentrated in the fovea (the central area of our vision) as these are the main cells we use for vision in the daytime. Rod cells are concentrated in the periphery and can detect much fainter light at night, but only see in grey scale. The Northern Lights appear to us in shades of grey because the light is too faint to be seen by our (colour-detecting) central cone cells.
DSLR camera sensors don’t have the same limitation as our eyes. Couple that fact with long exposure times and high ISO settings of modern cameras, and it becomes quite evident that the camera sensor has a much higher dynamic range of vision in the dark than we do!
Hayley Brunsden | CBTR Opticians, Beaconsfield
I have always been extremely passionate about exceptional client care. After working in different optical practices since 2010 I felt the optical industry needed a cultural reset, and so began building the CBTR brand; a business wholeheartedly committed to sustainability whilst never compromising in quality or care.Â
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