<s>
The	O
Canon	B-Algorithm
EOS	I-Algorithm
20D	O
is	O
an	O
8.2-megapixel	O
semi-professional	O
digital	B-Device
single-lens	I-Device
reflex	I-Device
camera	I-Device
,	O
initially	O
announced	O
on	O
19	O
August	O
2004	O
at	O
a	O
recommended	O
retail	O
price	O
of	O
US$	O
1,499	O
.	O
</s>
<s>
It	O
is	O
the	O
successor	O
of	O
the	O
EOS	B-Algorithm
10D	I-Algorithm
,	O
and	O
was	O
succeeded	O
by	O
the	O
EOS	B-Device
30D	I-Device
in	O
August	O
2006	O
.	O
</s>
<s>
It	O
accepts	O
EF	B-Application
and	O
EF-S	B-Algorithm
lenses	I-Algorithm
and	O
uses	O
an	O
APS-C	B-Algorithm
sized	O
image	O
sensor	O
.	O
</s>
<s>
The	O
20D	O
supports	O
USB	B-Protocol
2.0	O
.	O
</s>
<s>
The	O
Canon	B-Algorithm
EOS	I-Algorithm
20D	O
has	O
several	O
resolution	O
settings	O
:	O
</s>
<s>
The	O
20D	O
is	O
the	O
first	O
Canon	O
prosumer	O
camera	O
to	O
use	O
the	O
EF-S	B-Algorithm
lens	I-Algorithm
mount	I-Algorithm
;	O
the	O
first	O
Canon	B-Algorithm
EOS	I-Algorithm
camera	O
to	O
use	O
the	O
mount	O
was	O
the	O
300D	B-Algorithm
(	O
the	O
Digital	B-Algorithm
Rebel	I-Algorithm
in	O
North	O
America	O
)	O
.	O
</s>
<s>
Av	O
(	O
Aperture	B-Algorithm
priority	I-Algorithm
)	O
:	O
The	O
camera	O
lets	O
the	O
user	O
choose	O
the	O
aperture	O
(	O
f/	O
)	O
value	O
and	O
then	O
automatically	O
adjusts	O
the	O
shutter	O
speed	O
for	O
correct	O
exposure	O
.	O
</s>
<s>
Tv	O
(	O
Shutter	B-Algorithm
speed	I-Algorithm
priority	I-Algorithm
)	O
:	O
The	O
camera	O
lets	O
the	O
user	O
set	O
the	O
shutter	O
speed	O
and	O
automatically	O
sets	O
the	O
aperture	O
for	O
correct	O
exposure	O
.	O
</s>
<s>
The	O
main	O
differences	O
between	O
the	O
20Da	O
and	O
20D	O
are	O
the	O
replacement	O
of	O
the	O
"	O
hot	O
mirror	O
"	O
infra-red	O
(	O
IR	O
)	O
filter	O
which	O
covers	O
the	O
CMOS	B-Architecture
sensor	I-Architecture
on	O
the	O
20D	O
and	O
live	B-Device
view	I-Device
mode	O
.	O
</s>
<s>
In	O
conventional	O
photography	O
,	O
the	O
IR	O
filter	O
is	O
used	O
to	O
make	O
the	O
spectral	O
response	O
of	O
the	O
CMOS	B-Architecture
sensor	I-Architecture
more	O
like	O
that	O
of	O
the	O
human	O
eye	O
.	O
</s>
<s>
It	O
is	O
extremely	O
difficult	O
to	O
focus	O
an	O
extremely	O
dim	O
image	O
with	O
a	O
reflex	O
viewfinder	O
;	O
locking	O
the	O
mirror	O
up	O
and	O
opening	O
the	O
shutter	O
(	O
live	B-Device
view	I-Device
)	O
was	O
introduced	O
in	O
the	O
20Da	O
to	O
address	O
this	O
issue	O
.	O
</s>
<s>
Live	B-Device
view	I-Device
for	O
this	O
application	O
requires	O
a	O
lens	O
which	O
supports	O
fully	O
mechanical	O
focus	O
in	O
manual	O
mode	O
,	O
and	O
is	O
not	O
suitable	O
for	O
normal	O
daytime	O
use	O
.	O
</s>
<s>
Reviews	O
report	O
that	O
image	O
noise	O
in	O
the	O
20Da	O
is	O
lower	O
than	O
in	O
the	O
20D	O
,	O
and	O
equivalent	O
to	O
that	O
of	O
the	O
5D	B-Algorithm
MkII	I-Algorithm
.	O
</s>
<s>
The	O
EOS	O
20Da	O
was	O
discontinued	O
when	O
the	O
30D	B-Device
was	O
introduced	O
in	O
2006	O
.	O
</s>
<s>
In	O
April	O
2012	O
,	O
Canon	O
announced	O
the	O
EOS	B-Algorithm
60Da	I-Algorithm
which	O
is	O
the	O
successor	O
to	O
the	O
EOS	O
20Da	O
.	O
</s>
<s>
The	O
latest	O
firmware	O
available	O
for	O
the	O
20D	O
(	O
and	O
believed	O
to	O
be	O
the	O
final	O
update	O
)	O
is	O
version	O
2.0.3	O
,	O
made	O
available	O
23	O
August	O
2005	O
,	O
which	O
improves	O
the	O
communication	O
reliability	O
with	O
some	O
CF	B-Device
cards	I-Device
and	O
other	O
minor	O
changes	O
.	O
</s>
