<s>
Digital	B-Algorithm
zoom	I-Algorithm
is	O
a	O
method	O
of	O
decreasing	O
the	O
precise	O
angle	O
of	O
view	O
of	O
a	O
digital	B-Application
photograph	I-Application
or	O
video	O
image	O
.	O
</s>
<s>
In	O
cameras	O
that	O
perform	O
lossy	B-Algorithm
compression	I-Algorithm
,	O
digital	B-Algorithm
zoom	I-Algorithm
is	O
preferred	O
to	O
enlargement	O
in	O
post-processing	O
,	O
as	O
the	O
zooming	O
may	O
be	O
applied	O
before	O
detail	O
is	O
lost	O
to	O
compression	O
.	O
</s>
<s>
In	O
cameras	O
that	O
save	O
in	O
a	O
lossless	O
format	O
,	O
resizing	O
in	O
post-production	O
yields	O
results	O
equal	O
or	O
superior	O
to	O
digital	B-Algorithm
zoom	I-Algorithm
.	O
</s>
<s>
Lower-end	O
camera	O
phones	O
use	O
only	O
digital	B-Algorithm
zoom	I-Algorithm
and	O
do	O
not	O
have	O
optical	O
zoom	O
,	O
while	O
many	O
higher-end	O
phones	O
have	O
additional	O
rear	O
cameras	O
,	O
including	O
fixed	O
telephoto	O
lenses	O
that	O
allow	O
for	O
the	O
simulation	O
of	O
optical	O
zoom	O
.	O
</s>
<s>
Full-sized	O
cameras	O
generally	O
have	O
an	O
optical	O
zoom	O
lens	O
,	O
but	O
some	O
apply	O
digital	B-Algorithm
zoom	I-Algorithm
automatically	O
once	O
the	O
longest	O
optical	O
focal	B-Algorithm
length	I-Algorithm
possible	O
has	O
been	O
reached	O
.	O
</s>
<s>
Professional	O
cameras	O
generally	O
do	O
not	O
feature	O
digital	B-Algorithm
zoom	I-Algorithm
.	O
</s>
<s>
An	O
optical	O
zoom	O
camera	O
can	O
be	O
zoomed	O
to	O
its	O
optical	O
limit	O
,	O
and	O
further	O
zooming	O
is	O
sometimes	O
allowed	O
by	O
digital	B-Algorithm
zoom	I-Algorithm
.	O
</s>
<s>
Digital	B-Algorithm
zoom	I-Algorithm
uses	O
the	O
centre	O
area	O
of	O
the	O
optical	O
image	O
to	O
enlarge	O
the	O
image	O
.	O
</s>
<s>
By	O
reducing	O
the	O
image	O
size	O
,	O
digital	B-Algorithm
zoom	I-Algorithm
occurs	O
without	O
image	O
deterioration	O
of	O
the	O
output	O
image	O
,	O
and	O
some	O
cameras	O
have	O
a	O
"	O
not-deteriorated	O
image	O
"	O
mode	O
or	O
an	O
image	O
deterioration	O
indicator	O
.	O
</s>
<s>
The	O
table	O
below	O
shows	O
the	O
not-deteriorated	O
zoom	O
limit	O
for	O
some	O
megapixel	O
(	O
MP	O
)	O
image	O
sizes	O
of	O
a	O
particular	O
camera	O
with	O
optical	O
zoom	O
24x	O
,	O
and	O
digital	B-Algorithm
zoom	I-Algorithm
4x	O
for	O
its	O
maximum	O
capability	O
:	O
</s>
<s>
Some	O
camera	O
firmwares	B-Application
store	O
lossily	O
digitally	O
zoomed	O
images	O
with	O
accordingly	O
reduced	O
dimensions	O
(	O
width	O
and	O
height	O
)	O
rather	O
than	O
upscaling	O
it	O
to	O
the	O
original	O
raster	B-Algorithm
resolution	O
.	O
</s>
<s>
The	O
intelligent	O
zoom	O
only	O
uses	O
the	O
centre	O
of	O
the	O
image	B-Algorithm
sensor	I-Algorithm
and	O
does	O
not	O
interpolate	O
the	O
original	O
resolution	O
,	O
so	O
the	O
resulting	O
image	O
quality	O
is	O
good	O
in	O
reduced	O
resolution	O
.	O
</s>
<s>
Hybrid	O
zoom	O
is	O
a	O
concept	O
used	O
in	O
smartphones	O
that	O
takes	O
advantage	O
of	O
optical	O
zoom	O
,	O
digital	B-Algorithm
zoom	I-Algorithm
,	O
and	O
software	O
to	O
get	O
improved	O
results	O
when	O
zooming	O
in	O
further	O
than	O
the	O
lens’	O
physical	O
capabilities	O
.	O
</s>
<s>
Trying	O
to	O
zoom	O
in	O
further	O
than	O
this	O
limit	O
may	O
result	O
in	O
loss	O
of	O
quality	O
as	O
the	O
camera	O
switches	O
to	O
digital	B-Algorithm
zoom	I-Algorithm
,	O
though	O
hybrid	O
zoom	O
may	O
mitigate	O
this	O
.	O
</s>
<s>
Many	O
cameras	O
,	O
including	O
mobile	O
phone	O
cameras	O
,	O
also	O
employ	O
lossless	O
digital	B-Algorithm
zoom	I-Algorithm
for	O
video	O
recording	O
by	O
using	O
the	O
spare	O
resolution	O
of	O
the	O
image	B-Algorithm
sensor	I-Algorithm
for	O
cropping	O
by	O
taking	O
advantage	O
of	O
used	O
video	O
frame	O
resolutions	O
often	O
being	O
significantly	O
below	O
the	O
available	O
resolution	O
of	O
the	O
image	B-Algorithm
sensors	I-Algorithm
.	O
</s>
<s>
This	O
means	O
that	O
,	O
for	O
example	O
,	O
if	O
implemented	O
correctly	O
by	O
the	O
camera	O
hardware	O
and	O
software	O
,	O
a	O
2160p	O
image	B-Algorithm
sensor	I-Algorithm
would	O
enable	O
up	O
to	O
2×	O
lossless	O
digital	B-Algorithm
zoom	I-Algorithm
for	O
1080p	O
video	O
recording	O
,	O
3×	O
for	O
720p	O
video	O
,	O
and	O
4.5	O
×	O
for	O
480p	O
video	O
by	O
using	O
image	B-Algorithm
sensor	I-Algorithm
cropping	O
.	O
</s>
<s>
The	O
terms	O
among	O
camera	O
and	O
image	B-Algorithm
sensor	I-Algorithm
manufacturers	O
are	O
"	O
Smart	O
Zoom	O
"	O
(	O
Sony	O
)	O
,	O
"	O
Safe	O
Zoom	O
"	O
(	O
Canon	O
)	O
,	O
"	O
Sensor	O
Crop	O
"	O
(	O
Cisco	O
)	O
and	O
"	O
Intelligent	O
Zoom	O
"	O
(	O
Panasonic	O
and	O
others	O
)	O
.	O
</s>
<s>
There	O
are	O
also	O
cameras	O
with	O
digital	B-Algorithm
zoom	I-Algorithm
functions	O
as	O
high	O
as	O
7.2	O
×	O
and	O
Smart	O
Zoom	O
with	O
approximately	O
30×	O
total	O
zoom	O
(	O
optical	O
zoom	O
20×	O
and	O
digital	B-Algorithm
zoom	I-Algorithm
1.5	O
×	O
)	O
for	O
7MP	O
from	O
16MP	O
total	O
resolution	O
,	O
and	O
also	O
144×	O
total	O
zoom	O
(	O
optical	O
zoom	O
20×	O
and	O
digital	B-Algorithm
zoom	I-Algorithm
7.2	O
×	O
)	O
for	O
VGA	O
640x480	O
.	O
</s>
<s>
Photographers	O
can	O
purposefully	O
employ	O
digital	B-Algorithm
zoom	I-Algorithm
for	O
the	O
characteristic	O
low-fidelity	O
appearance	O
of	O
the	O
images	O
it	O
produces	O
.	O
</s>
