Datasheet

moved with very small motors to counteract the unwant-
ed camera movements detected by a gyroscope.
If you lightly wobble the phone and listen to the camera,
you can actually hear the module that absorbs the shak-
ing of your hand. Once the camera is activated, give the
phone the same wobble and the magnets kick in and soak
up the movements.
Photos in the dark
The standard factor used for determining good low light
performance is the amount of visible noise in the im-
age captured. But there is a lot more to it than just the
amount of noise.
Back side illuminated sensor
It is extremely dicult to make a high resolution sensor
with just a small amount of visible noise because pixels
must be kept small to keep the sensor size reasonable.
The smaller pixel size is especially problematic with tra-
ditional front side illuminated (FSI) sensors, because each
pixel needs many wires to power up the photo diode and
to transfer the photons out from the pixel. With tradition-
al pixels all these wires are located on top of the pixels and
light must bypass the wires to reach the photosensitive
area of the pixel. We used a modern-generation BSI sen-
sor where all these wires are located underneath the pix-
el. With this design a signicantly larger amount of light
can actually reach the photosensitive area of the pixel.
This again means that we can amplify the signal created
by much lower levels of light, signicantly reducing the
amount of visible noise.
Exposure time
Another extremely important factor contributing to low
light performance is the exposure time. A camera can be
compared to a dam where the shutter plays the role of the
gate. The longer the gate is open, the more water can ow
through it. In a camera, the longer the shutter is open the
more light can be gathered by the sensor.
However, if the shutter is open too long, the captured im-
age can suer from hand-shake, which means reduced
sharpness. With its OIS system, the Nokia Lumia 1020
camera can actually tolerate up to of 3-5 times longer ex-
posure times compared to traditional mobile cameras – a
signicant benet in low light situations. Using the Lumia
1020 together with a tripod, users can manually set the
exposure time up to 4s, which allows you to take amazing
images in nearly complete darkness.
Flash
When discussing low light performance it´s only natural
to also consider the ash. Even though many prefer the
natural ambient feeling in images captured without ash,
even with the very best of cameras we occasionally run
into situations where the use of ash is mandatory, espe-
cially if the target is moving. Flash performance is often
assessed by comparing the light output of dierent ash-
es, however ash pulse duration is an equally important
parameter to consider.
Figure 7. Clever engineering: Ball bearings oat the large lens system. Illustration only.
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