Application of Small Lenses

Application of Small Lenses in
Smartphone and CCTV Camera

CHAPTER : LIGHT AND OPTICS

AISHA 4 NEBULA
NABEEN
DINIE

What is Small Lenses ?

A microlens is a small lens, generally with a diameter less than a millimetre
(mm) and often as small as 10 micrometres (µm). The small sizes of the lenses

means that a simple design can give good optical quality but sometimes
unwanted effects arise due to optical diffraction at the small features.

Application of 01 Small lenses are widely used in smartphone and closed-
Small Lenses circuit television (CCTV) cameras.

Not just smartphone, many gadget nowadays got small lenses. 02 Smartphone and CCTVs have cameras of high resolution to
capture pictures and record videos clearly.

03 Thin smartphone and all size CCTVs have small size convex
lenses. These lenses can form an image that is real,
diminished and inverted at the sensor

04 The minimum distance beetween the sensor and the
centre of the lens has to be the same as the focal length of
the camera lens.

05 The size of smartphone and CCTV cannot be smaller than
the focal length of the camera lens

Smartphone Tablet

Laptop Computer

Lenses in Smartphone

What are smartphone lenses ? INFO Back
Lenses
The purpose of attachable smartphone lenses is to enhance Front
your mobile photography experiencing by expanding on the Lenses
visual capacity of a smartphone's camera. This is done by
changing the phone camera's focal length and angle-of-
view, or how much of the scene can fit in the frame of the
shot.

There are two popular ways to attach an external lens to a
smartphone-- via a lens clip or a special phone case. Mobile
camera lenses that attach to a phone via a lens clip usually
can be used with a wide variety of smartphone models
because, in most cases, they can be adjusted to fit the
position of any smartphone’s camera array.

Function of small lenses in smartphone camera INFO

Turning over to the back of your phone you are going to Types of lenses
find a tiny camera lens. A dual-camera system can help
you get sharper image detail, enable an ultra-wide-angle a telephoto lens with a very large focal
mode, and capture epic portraits with a shallow depth of length(the distance at which a clear photo can
field, as well as set up a better and sharper optical zoom still be formed)
an ultra-wide lens with a small focal length
How do smart phone lenses work? a wide lens that falls in between these two
focal ranges
Essentially, an infrared light is built into your camera
system. When taking a picture, infrared light will be Wide Ultra-Wide
emitted and the time it takes for the beam to return Camera Camera
from your subject will be used to calculate your
distance from the subject, and the lens is adjusted Telephoto
accordingly. Camera

What does focal length mean? What does the focal length of a lens mean?

Measured in millimetres (mm), the term ‘focal Lens focal length tells us the angle of view. How
length’ refers to the distance between the much of the scene will be captured and the
camera’s image sensor and where light magnification, How large individual elements will
converges and focuses the image inside the lens. be. The longer the focal length, the narrower the
angle of view and the higher the magnification. The

shorter the focal length, the wider the angle of view
When light travels, it travels in parallel lines. If a and the lower the magnification.
single convex lens is put in front of it, the
parallel light rays will converge and bend
towards a single point-- the focal point.

How is focal Length different in smartphones? Camera Sensor Lens and Sensor Haardware

Because space is very valuable real estate in
smartphones, mobile cameras are very small and
have tiny sensors compared to the likes of a full-
frame DSLR camera.

As a result, the actual distance between where the
image is focused inside the lens to where it’s
captured on the sensor is very short. In fact, a
smartphone camera marketed as having a 26mm
lens actually has a focal length of 4.25mm

For this reason, you’ll find that the focal length of the Sensor with lens
phone’s lens or lenses is expressed in the equivalent of a
35mm-format sensor instead of the smartphone’s own.

Small Size CCTV

Fixed Varifocal
Lens Lens

Fixed focal length, meaning What are can choose between a manual
that you cannot adjust the field Lenses in or motorised lens
of view
CCTV ? variable focal length, meaning
typically have a smaller that the field of view can be
camera size than a varifocal adjusted and fine-tuned
lens cameras
A CCTV security camera that typically have a larger camera
at a low price point (budget has a fixed lens is size than a fixed lens camera due
friendly option) to motorised lens
permanently set, meaning
that its angle of view, focal
length and level of zoom
cannot be changed. although they are more

expensive than fixed lens cameras,
varifocal CCTV cameras provide more

flexibility in their usage especially

in a retail setting. This helps the

customer get the most value of

over the camera over a
longer period of time

Function of small lenses in CCTV camera INFO

The simplest CCTV lens is a piece of glass (or plastic) to focus Types of CCTV cameras
the light from the outside world onto the camera's imaging
sensor. This lens' only adjustable mechanism is its focus- Dome CCTV Cameras
ring, part of the barrel body, which you turn until your image 360-degree rotation of the
is as clear as possible. camera so you can cover all
angles
What is CCTV lens size?
Bullet CCTV Cameras
The camera lenses that CCTV Camera Pros supplies Provides surveillance over
generally range from 2.5mm to 100mm. The larger the long distances
size of the lens, the more narrow and zoomed in the
field of view is. Some of our fixed lens cameras come
standard with a 3.6mm or 6mm lens.

Field of View

Field of view is the area of coverage that the camera can ‘see’ within a scene. This all depends
on the size of the lens. Diagram below shows you the sort of coverage you expect from different
lens sizes.

2.8mm 4mm 6mm

The higher the number, the
narrower a view you have.

What lens do you need?

2.8mm for a 90° view
popular choice for static camera surveillance
can cover a wide area with just one camera.
very popular indoors

4mm for a 60° view
Shows a similar scene to the 2.8mm
Main difference is the reduced angle of view which gives the illusion that objects are closer to the camera
Useful for detection & identification.
Often used in outdoor areas like car parks
lts also helpful when you want a narrower view to avoid monitoring unnecessary areas

6mm for a 45° telephoto view
Gives a narrow, but detailed distance view
Can also be used to monitor a specific object like tills.
Customers often use this lens for monitoring the entrance to a car park, or a doorway.
It’s also useful for a corridor, especially when combined with corridor format/view technology

A 2.8mm lens produces a wide view which is great for general surveillance. While a
narrower, telephoto lens is more suitable for looking at specific object.

Thank You