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Why doesn't all dust appear
on camera between these points?
Final Factor: The Flash
So far we have learnt that
dust between the two vertical lines, below, appears so
large and out-of-focus as to produce orbs.
But orbs do not appear
everywhere in this area (the area looking like a
triangle with the top cut off) because the area is
further limited by the flash (the white circle in the
diagram):
Why is the flash so
important?
One crucial thing we haven't
mentioned so far is that 'orb capture' is not possible
without an intensive light source. In the vast
majority of cases this is the camera flash, but in some
cases it can be sunlight and other sources.
The reason for this is
slightly complicated. Orbs are actually
out-of-focus reflected highlights -
see here for more
details.
Does such a small distance
make really make a difference?
It makes a big difference!
According to Newton's inverse square law states that if
an object is twice the distance from the light source it
receives one quarter of the light.
So a particle of dust 3
centremetres from a camera flash would be 8 times more
illuminated than a particle just 9 centremetres from the
flash!
This is one of the
reasons why larger cameras (such as
SLR
cameras) produce fewer orbs than compact cameras -
because the flash is mounted further from the lens area.
Next Questions:
- Summary: what we know about
the 'Orb Zone'? |
