<s>
Live	B-Device
preview	I-Device
is	O
a	O
feature	O
that	O
allows	O
a	O
digital	B-Device
camera	I-Device
's	I-Device
display	O
screen	O
to	O
be	O
used	O
as	O
a	O
viewfinder	O
.	O
</s>
<s>
This	O
provides	O
a	O
means	O
of	O
previewing	O
framing	O
and	O
other	O
exposure	O
before	O
taking	O
the	O
photograph	B-Application
.	O
</s>
<s>
In	O
most	O
such	O
cameras	O
,	O
the	O
preview	O
is	O
generated	O
by	O
means	O
of	O
continuously	O
and	O
directly	O
projecting	O
the	O
image	O
formed	O
by	O
the	O
lens	O
onto	O
the	O
main	O
image	B-Algorithm
sensor	I-Algorithm
.	O
</s>
<s>
This	O
in	O
turn	O
feeds	O
the	O
electronic	O
screen	O
with	O
the	O
live	B-Device
preview	I-Device
image	O
.	O
</s>
<s>
The	O
electronic	O
screen	O
can	O
be	O
either	O
a	O
liquid	B-Device
crystal	I-Device
display	I-Device
(	O
LCD	B-Device
)	O
or	O
an	O
electronic	B-Algorithm
viewfinder	I-Algorithm
(	O
EVF	O
)	O
.	O
</s>
<s>
The	O
concept	O
for	O
cameras	O
with	O
live	B-Device
preview	I-Device
largely	O
derives	O
from	O
electronic	O
(	O
video	O
)	O
TV	O
cameras	O
.	O
</s>
<s>
Until	O
1995	O
most	O
digital	B-Device
cameras	I-Device
did	O
not	O
have	O
live	B-Device
preview	I-Device
,	O
and	O
it	O
was	O
more	O
than	O
ten	O
years	O
after	O
this	O
that	O
the	O
higher	O
end	O
digital	B-Device
single-lens	I-Device
reflex	I-Device
cameras	I-Device
(	O
DSLR	B-Device
)	O
adopted	O
this	O
feature	O
,	O
as	O
it	O
is	O
fundamentally	O
incompatible	O
with	O
the	O
swinging-mirror	O
single-lens	B-Algorithm
reflex	I-Algorithm
mechanism	O
.	O
</s>
<s>
The	O
first	O
digital	B-Device
still	I-Device
camera	I-Device
with	O
an	O
LCD	B-Device
for	O
autogain	O
framing	O
live	B-Device
preview	I-Device
was	O
the	O
Casio	O
QV-10	O
in	O
1995	O
.	O
</s>
<s>
The	O
first	O
prosumer	O
camera	O
to	O
use	O
live	B-Device
view	I-Device
for	O
both	O
exposure	O
simulation	O
live	B-Device
preview	I-Device
ES-LV	O
control	O
and	O
live	B-Device
preview	I-Device
framing	O
was	O
the	O
fixed-lens	O
Canon	B-Device
PowerShot	I-Device
G1	I-Device
from	O
2000	O
(	O
possibly	O
the	O
first	O
was	O
Canon	O
Powershot	O
Pro70	O
in	O
1998	O
)	O
,	O
although	O
this	O
was	O
still	O
in	O
the	O
line	O
of	O
compact	O
cameras	O
.	O
</s>
<s>
The	O
first	O
DSLR	B-Device
to	O
use	O
live	B-Device
view	I-Device
for	O
framing	O
preview	O
only	O
,	O
like	O
early	O
other	O
live	B-Device
view	I-Device
but	O
non-mirrored	O
digicams	B-Device
,	O
was	O
the	O
fixed-lens	O
Olympus	B-Algorithm
E-10	I-Algorithm
from	O
2000	O
.	O
</s>
<s>
The	O
first	O
interchangeable-lens	O
DSLR	B-Device
to	O
use	O
a	O
live	B-Device
preview	I-Device
for	O
framing	O
was	O
the	O
Fujifilm	B-Device
FinePix	I-Device
S3	I-Device
Pro	I-Device
,	O
which	O
was	O
launched	O
in	O
October	O
2004	O
.	O
</s>
<s>
The	O
first	O
interchangeable-lens	O
DSLR	B-Device
following	O
ES-LV	O
capabilities	O
of	O
Canon	O
's	O
Powershot	B-Device
G1	I-Device
(	O
maybe	O
,	O
Canon	O
Powershot	O
Pro70	O
)	O
was	O
in	O
early	O
2005	O
with	O
the	O
Canon	B-Algorithm
EOS	I-Algorithm
20Da	I-Algorithm
,	O
a	O
special	O
version	O
of	O
the	O
Canon	B-Algorithm
EOS	I-Algorithm
20D	I-Algorithm
with	O
exposure	O
simulation	O
live	B-Device
view	I-Device
modifications	O
for	O
astrophotography	O
,	O
which	O
included	O
a	O
similar	O
focus	O
preview	O
feature	O
,	O
plus	O
first	O
ever	O
for	O
any	O
DSLR	B-Device
the	O
new	O
exposure	O
simulation	O
live	B-Device
view	I-Device
allowed	O
capture	O
of	O
star	O
exposures	O
to	O
selectable	O
brightness	O
'	O
effects	O
 '	O
(	O
Canon	O
ExpSim	O
LV	O
)	O
.	O
</s>
<s>
The	O
first	O
general-use	O
interchangeable-lens	O
DSLRs	B-Device
with	O
live	B-Device
view	I-Device
for	O
both	O
exposure	O
simulated	O
live	B-Device
preview	I-Device
(	O
ExpSim	O
LV	O
)	O
and	O
framing	O
livepreview	O
were	O
the	O
Canon	O
20Da	B-Algorithm
of	O
2005	O
,	O
followed	O
by	O
Canon	B-Algorithm
EOS	I-Algorithm
1Ds	I-Algorithm
Mark	I-Algorithm
III	I-Algorithm
and	O
Canon	B-Device
EOS	I-Device
40D	I-Device
of	O
2007	O
.	O
</s>
<s>
The	O
first	O
general-use	O
interchangeable-lens	O
DSLR	B-Device
with	O
live	B-Device
view	I-Device
for	O
framing	O
preview	O
only	O
like	O
most	O
fixed	O
lens	O
digicams	B-Device
was	O
the	O
Olympus	B-Algorithm
E-330	I-Algorithm
of	O
2006	O
.	O
</s>
<s>
There	O
are	O
two	O
distinct	O
modes	O
of	O
live-preview	B-Device
,	O
with	O
only	O
a	O
few	O
manufacturers	O
offering	O
both	O
in	O
their	O
digital	B-Device
cameras	I-Device
.	O
</s>
<s>
The	O
first	O
is	O
a	O
more	O
rudimentary	O
type	O
of	O
live	B-Device
preview	I-Device
that	O
displays	O
the	O
overall	O
framing	O
on	O
an	O
electronic	O
display	O
and	O
allows	O
a	O
preview	O
of	O
what	O
the	O
camera	O
's	O
sensor	O
will	O
detect	O
before	O
the	O
photograph	B-Application
is	O
taken	O
.	O
</s>
<s>
This	O
type	O
of	O
live	B-Device
preview	I-Device
is	O
the	O
autogain/framing	O
live	B-Device
view	I-Device
type	O
(	O
or	O
framing	O
priority	O
display	O
)	O
.	O
</s>
<s>
The	O
second	O
is	O
a	O
more	O
sophisticated	O
type	O
of	O
live	B-Device
preview	I-Device
that	O
displays	O
the	O
exact	O
exposure	O
'	O
look	O
 '	O
on	O
an	O
electronic	O
display	O
and	O
allows	O
the	O
photographer	O
to	O
alter	O
the	O
exposure	O
look	O
via	O
adjustments	O
to	O
parameters	O
such	O
as	O
shutter	O
speed	O
,	O
film	O
speed	O
or	O
ISO	O
,	O
and	O
aperture	B-General_Concept
,	O
before	O
the	O
photograph	B-Application
is	O
taken	O
.	O
</s>
<s>
This	O
second	O
type	O
of	O
live	B-Device
preview	I-Device
is	O
the	O
exposure	O
simulation	O
live	B-Device
preview	I-Device
type	O
(	O
or	O
exposure	O
priority	O
display	O
)	O
.	O
</s>
<s>
This	O
type	O
of	O
live	B-Device
preview	I-Device
eliminates	O
reliance	O
on	O
traditional	O
light	O
metering	O
usage	O
.	O
</s>
<s>
Many	O
modern	O
bridge	O
and	O
compact	O
cameras	O
with	O
movie	O
mode	O
have	O
only	O
an	O
automatic	O
exposure	O
and	O
limited	O
exposure	O
compensation	O
control	O
,	O
and	O
live	B-Device
view	I-Device
that	O
is	O
primarily	O
for	O
framing	O
only	O
.	O
</s>
<s>
Live-preview-only	O
cameras	O
,	O
that	O
is	O
cameras	O
without	O
an	O
optical	O
viewfinder	O
,	O
include	O
four	O
different	O
categories	O
:	O
compact	O
digital	B-Device
cameras	I-Device
,	O
bridge	B-Device
digital	I-Device
cameras	I-Device
,	O
and	O
the	O
newer	O
mirrorless	B-Device
interchangeable	I-Device
lens	I-Device
cameras	I-Device
and	O
Sony	B-Device
SLT	I-Device
cameras	I-Device
.	O
</s>
<s>
Bridge	B-Device
cameras	I-Device
in	O
general	O
are	O
higher-end	O
,	O
that	O
is	O
they	O
contain	O
more	O
advanced	O
features	O
,	O
better	O
build	O
quality	O
,	O
larger	O
size	O
,	O
and	O
are	O
more	O
expensive	O
than	O
compacts	O
,	O
but	O
retain	O
a	O
small	O
digital	O
sensor	O
.	O
</s>
<s>
Mirrorless	B-Device
cameras	I-Device
feature	O
a	O
larger	O
sensor	O
and	O
interchangeable	O
lenses	O
,	O
like	O
DSLRs	B-Device
,	O
but	O
sacrifice	O
the	O
SLR	B-Algorithm
mirror	O
mechanism	O
and	O
viewfinder	O
to	O
save	O
size	O
and	O
cost	O
,	O
and	O
hence	O
only	O
offer	O
live	B-Device
preview	I-Device
.	O
</s>
<s>
The	O
SLT	O
,	O
developed	O
by	O
Sony	B-Algorithm
,	O
uses	O
a	O
mirror	O
similar	O
to	O
that	O
found	O
in	O
a	O
DSLR	B-Device
.	O
</s>
<s>
However	O
,	O
unlike	O
the	O
moving	O
and	O
fully	O
reflective	O
mirror	O
of	O
DSLRs	B-Device
,	O
the	O
SLT	O
mirror	O
is	O
fixed	O
and	O
semi-reflective	O
.	O
</s>
<s>
New	O
Zealand-based	O
British	O
photographer	O
Gordon	O
Laing	O
describes	O
the	O
technology:"[A]	O
fixed	O
semi-reflective	O
mirror	O
allows	O
around	O
70%	O
of	O
the	O
light	O
to	O
pass	O
through	O
to	O
the	O
sensor	O
for	O
full-time	O
live	B-Device
view	I-Device
composition	O
,	O
but	O
reflects	O
the	O
remaining	O
30%	O
or	O
so	O
to	O
the	O
phase	O
change	O
AF	O
system	O
,	O
allowing	O
quick	O
and	O
continuous	O
autofocusing	O
in	O
Live	B-Device
View	I-Device
and	O
movie	O
modes	O
.	O
</s>
<s>
30%	O
is	O
however	O
too	O
little	O
for	O
a	O
traditional	O
optical	O
viewfinder	O
,	O
so	O
Sony	B-Algorithm
does	O
n't	O
bother	O
,	O
instead	O
using	O
the	O
main	O
sensor	O
to	O
deliver	O
a	O
live	O
image	O
to	O
an	O
electronic	B-Algorithm
viewfinder	I-Algorithm
in	O
addition	O
to	O
the	O
main	O
rear	O
screen	O
for	O
composition.	O
"	O
</s>
<s>
The	O
same	O
technology	O
was	O
used	O
by	O
Olympus	O
prior	O
to	O
Sony	B-Algorithm
in	O
the	O
Olympus	O
E-u	O
.	O
</s>
<s>
Early	O
examples	O
of	O
Exposure	O
Simulation	O
Live	B-Device
View	I-Device
(	O
ES-LV	O
)	O
in	O
advanced	O
prosumer	O
digicams	B-Device
with	O
Full	O
Manual	O
/	O
Manual	O
ISO	O
,	O
such	O
as	O
Canon	O
's	O
PowerShot	O
Pro70	O
(	O
1998	O
)	O
,	O
Powershot	B-Device
G1	I-Device
(	O
2000	O
)	O
and	O
Powershot	O
Pro90	O
IS	O
(	O
2001	O
)	O
,	O
all	O
feature	O
an	O
optical	O
viewfinder	O
or	O
optical	O
tunnel	O
and	O
display	O
the	O
preview	O
image	O
on	O
their	O
vari-angle	O
swivel	O
screen	O
LCD	B-Device
.	O
</s>
<s>
This	O
gives	O
a	O
live	O
real-time	O
WYSIWYG	O
(	O
what	O
you	O
see	O
is	O
what	O
you	O
get	O
)	O
exposure	O
simulation	O
preview	O
in	O
Full	O
Manual	O
/	O
Manual	O
ISO	O
mode	O
,	O
and	O
Auto-Exposure	O
(	O
AE	O
)	O
/	O
Manual	O
ISO	O
modes	O
:	O
P	O
(	O
Program	O
)	O
,	O
TV	O
(	O
Time	O
Value	O
:	O
shutter	O
speed	O
priority	O
)	O
,	O
and	O
Av	O
(	O
Aperture	B-General_Concept
Value	O
)	O
.	O
</s>
<s>
If	O
Auto	O
ISO	O
is	O
used	O
,	O
Autogain	O
(	O
Auto-EV0	O
)	O
framing/focus	O
live	B-Device
view	I-Device
suspends	O
Exposure	O
Simulation	O
live	B-Device
view	I-Device
.	O
</s>
<s>
This	O
advanced	O
exposure	O
simulation	O
live	O
(	O
pre	O
-	O
)	O
view	O
ES-LV	O
on	O
Canon	O
's	O
prosumer	O
Powershots	O
was	O
absent	O
on	O
all	O
interchangeable-lens	O
DSLRs	B-Device
till	O
Canon	O
introduced	O
a	O
first	O
ES-LV	O
for	O
an	O
interchangeable-lens	O
DSLR	B-Device
(	O
they	O
dubbed	O
it	O
:	O
"	O
ExpSim	O
LV	O
"	O
version	O
)	O
in	O
its	O
EOS	O
20Da	B-Algorithm
,	O
to	O
preview	O
star	O
exposures	O
live	O
,	O
which	O
was	O
similar	O
to	O
ES-LV	O
found	O
in	O
its	O
advanced	O
prosumer	O
Powershot	O
digicams	B-Device
.	O
</s>
<s>
Later	O
,	O
Canon	O
extended	O
its	O
more	O
sophisticated	O
DSLR	B-Device
ExpSim	O
LV	O
all	O
shooting	O
light	O
conditions	O
like	O
its	O
Powershot	O
digicams	B-Device
.	O
</s>
<s>
The	O
most	O
significant	O
advances	O
and	O
difference	O
in	O
DSLR	B-Device
version	O
of	O
ES-LV	O
was	O
simulating	O
exposure	O
changes	O
effects	O
with	O
chosen	O
aperture	B-General_Concept
changes	O
without	O
stopping	O
down	O
the	O
aperture	B-General_Concept
.	O
</s>
<s>
The	O
ES-LV	O
of	O
its	O
Powershot	O
digicams	B-Device
always	O
kept	O
its	O
apertures	B-General_Concept
stopped	O
down	O
,	O
so	O
no	O
'	O
aperture	B-General_Concept
exposure	O
simulation	O
 '	O
was	O
needed	O
,	O
and	O
briefly	O
opened	O
aperture	B-General_Concept
to	O
assess	O
focus	O
with	O
shutter	O
button	O
partially	O
depressed	O
before	O
a	O
shot	O
is	O
taken	O
.	O
</s>
<s>
The	O
ExpSim	O
LV	O
of	O
its	O
EOS	O
lens	O
DSLRs	B-Device
could	O
achieve	O
the	O
same	O
'	O
exposure	O
simulation	O
 '	O
effect	O
in	O
both	O
aperture	B-General_Concept
stop-down	O
mode	O
and	O
aperture	B-General_Concept
wide	O
open	O
of	O
its	O
EOS	O
lenses	O
,	O
even	O
if	O
the	O
aperture	B-General_Concept
selection	O
was	O
narrower	O
than	O
widest	O
diameter	O
(	O
wide	O
open	O
)	O
.	O
</s>
<s>
In	O
Autogain	O
framing	O
live	B-Device
view	I-Device
,	O
such	O
as	O
in	O
AE	O
modes	O
with	O
Auto	O
ISO	O
in	O
effect	O
,	O
using	O
the	O
dof	O
button	O
can	O
take	O
on	O
two	O
different	O
effects	O
:	O
autogain	O
during	O
aperture	B-General_Concept
stopped	O
down	O
(	O
easy	O
to	O
see	O
dof	O
preview	O
)	O
,	O
and	O
autogain-locked	O
or	O
suspended	O
during	O
aperture	B-General_Concept
stopped	O
down	O
(	O
difficult	O
to	O
see	O
dof	O
,	O
just	O
like	O
looking	O
with	O
a	O
non-live	O
view	O
DSLR	B-Device
of	O
optical	O
viewfinder	O
(	O
OVF	O
)	O
preview	O
through-the-lens	O
(	O
TTL	O
)	O
.	O
</s>
<s>
For	O
ES-LV	O
digicam	B-Device
users	O
and	O
ExpSim	O
LV	O
DSLR	B-Device
users	O
,	O
this	O
advanced	O
method	O
of	O
"	O
Adjustable/Selectable	O
Live	O
Previewable	O
Exposure	O
Evaluation/Determination	O
"	O
shooting	O
in	O
Full	O
Manual	O
/	O
M	O
ISO	O
mode	O
completely	O
eliminated	O
light	O
meter	O
sensor	O
reading	O
TTL	O
common	O
from	O
the	O
film	O
era	O
,	O
making	O
optimally	O
desired	O
exposure	O
selection	O
with	O
live	B-Device
preview	I-Device
rear	O
monitor	O
screens	O
virtually	O
"	O
instant	O
at	O
a	O
glance	O
"	O
,	O
and	O
time	O
was	O
saved	O
doing	O
any	O
spot/area	O
evaluative	O
light	O
metering	O
TTL	O
,	O
which	O
non-ES-LV	O
and	O
totally	O
non-LV	O
DSLR	B-Device
users	O
doing	O
the	O
TTL	O
"	O
light	O
meter	O
reading	O
"	O
routine	O
,	O
same	O
as	O
their	O
film	O
SLR	B-Algorithm
counterparts	O
.	O
</s>
<s>
The	O
time	O
saved	O
assessing	O
instant	O
optimal	O
exposure	O
choices	O
for	O
any	O
new	O
or	O
changing	O
lit	O
scenario	O
,	O
freed	O
the	O
ExpSim	O
LV	O
DSLR	B-Device
users	O
to	O
spend	O
all	O
their	O
time	O
shooting	O
primarily	O
with	O
their	O
optical	O
viewfinder	O
(	O
OVF	O
)	O
.	O
</s>
<s>
When	O
interchangeable-lens	O
DSLRs	B-Device
with	O
STILLS	O
only	O
ExpSim	O
LV	O
(	O
APS-C	O
EOS	O
20Da	B-Algorithm
,	O
APS-H	O
EOS	O
1DMkIII	O
,	O
Full	O
Frame	O
(	O
FF	O
)	O
EOS	O
1DsMkIII	B-Algorithm
)	O
,	O
with	O
its	O
ExpSim	O
LV	O
having	O
Full	O
Manual	O
/	O
M/Auto	O
-ISO	O
mode	O
and	O
AE	O
/	O
M/Auto	O
-ISO	O
mode	O
,	O
ExpSim	O
LV	O
was	O
extended	O
for	O
the	O
first	O
time	O
in	O
any	O
interchangeable-lens	O
DSLR	B-Device
to	O
Canon	O
's	O
FF	O
ExpSim	O
LV	O
(	O
1080p	O
)	O
video	O
in	O
5DMkIII	O
,	O
it	O
was	O
only	O
then	O
,	O
did	O
use	O
of	O
OVF	O
shifted	O
over	O
,	O
more	O
to	O
the	O
rear	O
lcd	B-Device
monitor	O
to	O
shoot	O
Cinematic	O
(	O
larger	O
FF	O
sensor	O
frame	O
than	O
pro	O
digital	O
Super35mm	O
and	O
35mm	O
Cine	O
cameras	O
)	O
.	O
</s>
<s>
The	O
lesser	O
Autogain	O
Framing/Focus	O
Live	B-Device
preview	I-Device
,	O
borrowed	O
from	O
framing/focus	O
autogain	O
live	B-Device
view	I-Device
digicams	B-Device
,	O
in	O
lesser	O
autogain	O
live	B-Device
view	I-Device
DSLRs	B-Device
does	O
not	O
typically	O
serve	O
as	O
their	O
principal	O
means	O
of	O
framing	O
and	O
previewing	O
before	O
taking	O
a	O
photograph	B-Application
,	O
with	O
this	O
function	O
still	O
being	O
mainly	O
performed	O
with	O
optical	O
viewfinder	O
.	O
</s>
<s>
The	O
first	O
interchangeable-lens	O
DSLR	B-Device
to	O
feature	O
framing	O
live	B-Device
preview	I-Device
was	O
the	O
2004	O
Fujifilm	B-Device
FinePix	I-Device
S3	I-Device
Pro	I-Device
.	O
</s>
<s>
While	O
initially	O
largely	O
a	O
novelty	O
feature	O
,	O
framing/focus	O
only	O
live-preview	B-Device
functionality	O
from	O
digicam	B-Device
framing/focus	O
live	B-Device
view	I-Device
has	O
become	O
more	O
common	O
on	O
DSLR	B-Device
cameras	I-Device
,	O
and	O
almost	O
all	O
new	O
DSLRs	B-Device
have	O
had	O
the	O
feature	O
since	O
mid-2008	O
.	O
</s>
<s>
This	O
is	O
particularly	O
the	O
case	O
since	O
the	O
advent	O
of	O
movie	O
mode	O
common	O
to	O
digicam	B-Device
video	O
features	O
on	O
these	O
cameras	O
.	O
</s>
<s>
The	O
following	O
lists	O
,	O
for	O
each	O
brand	O
and	O
DSLR	B-Device
product	O
line	O
,	O
the	O
first	O
camera	O
to	O
have	O
live	B-Device
preview	I-Device
(	O
product	O
lines	O
that	O
did	O
not	O
exist	O
when	O
live	B-Device
preview	I-Device
came	O
into	O
use	O
are	O
not	O
shown	O
;	O
as	O
of	O
August	O
2014	O
,	O
there	O
is	O
no	O
product	O
line	O
in	O
which	O
live	B-Device
preview	I-Device
has	O
been	O
abandoned	O
after	O
being	O
introduced	O
)	O
:	O
</s>
<s>
The	O
principal	O
function	O
of	O
live	B-Device
preview	I-Device
on	O
Canon	O
DSLRs	B-Device
from	O
the	O
20Da	B-Algorithm
onwards	O
has	O
been	O
to	O
allow	O
,	O
via	O
LCD	B-Device
viewing	O
,	O
rapid	O
acquisition	O
of	O
consistent	O
and	O
predictable	O
exposure	O
selection	O
before	O
taking	O
a	O
photograph	B-Application
via	O
its	O
'	O
exposure	O
simulation	O
 '	O
(	O
ExpSim	O
)	O
enabled	O
mode	O
,	O
or	O
exposure	O
priority	O
display	O
.	O
</s>
<s>
This	O
mode	O
replaces	O
the	O
shortcomings	O
of	O
traditional	O
estimation	O
involved	O
in	O
the	O
through-the-lens	O
(	O
TTL	O
)	O
metering	O
techniques	O
of	O
the	O
older	O
framing	O
type	O
live	B-Device
view	I-Device
DSLRs	B-Device
with	O
autogain/framing	O
only	O
,	O
DSLRs	B-Device
without	O
live	B-Device
view	I-Device
,	O
as	O
well	O
as	O
the	O
shortcomings	O
of	O
optical	O
viewfinders	O
when	O
ambient	O
lighting	O
becomes	O
too	O
low	O
.	O
</s>
<s>
Real-time	O
exposure	O
simulation	O
live	B-Device
preview	I-Device
(	O
or	O
exposure	O
priority	O
display	O
)	O
had	O
been	O
available	O
in	O
many	O
prosumer	O
cameras	O
,	O
such	O
as	O
the	O
Canon	B-Device
PowerShot	I-Device
G	I-Device
series	O
,	O
before	O
being	O
available	O
to	O
in	O
live	B-Device
view	I-Device
DSLRs	B-Device
.	O
</s>
<s>
Some	O
manufacturers	O
of	O
compact	O
cameras	O
,	O
including	O
prosumer	O
models	O
,	O
still	O
lack	O
this	O
exposure	O
simulation	O
live	B-Device
view	I-Device
feature	O
,	O
instead	O
relying	O
on	O
the	O
more	O
rudimentary	O
autogain/framing	O
only	O
live	B-Device
view	I-Device
,	O
where	O
slow	O
focus	O
and	O
slow	O
exposure	O
estimation	O
via	O
TTL	O
metering	O
techniques	O
are	O
relied	O
upon	O
.	O
</s>
<s>
Real-time	O
exposure	O
simulation	O
capable	O
live	B-Device
preview	I-Device
digital	B-Device
cameras	I-Device
make	O
achieving	O
the	O
desired	O
exposures	O
,	O
especially	O
in	O
manual	O
modes	O
,	O
more	O
quickly	O
available	O
for	O
both	O
still	O
and	O
video	O
photography	O
.	O
</s>
<s>
Among	O
the	O
DSLRs	B-Device
that	O
do	O
manage	O
to	O
focus	O
using	O
the	O
standard	O
phase-detection	O
sensors	O
used	O
by	O
DSLRs	B-Device
,	O
unlike	O
some	O
compact	O
digital	B-Device
cameras	I-Device
none	O
has	O
managed	O
to	O
show	O
100%	O
frame	O
coverage	O
.	O
</s>
<s>
This	O
removes	O
one	O
of	O
the	O
key	O
advantages	O
of	O
live	B-Device
preview	I-Device
over	O
optical	O
viewfinders	O
,	O
especially	O
on	O
more	O
budget	O
cameras	O
.	O
</s>
<s>
Additionally	O
,	O
100%	O
coverage	O
optical	O
viewfinders	O
have	O
recently	O
become	O
more	O
common	O
and	O
affordable	O
with	O
the	O
appearance	O
of	O
the	O
Canon	B-Algorithm
EOS	I-Algorithm
7D	I-Algorithm
,	O
Nikon	B-Algorithm
D300	I-Algorithm
,	O
Olympus	B-Algorithm
E-3	I-Algorithm
and	O
the	O
Pentax	B-Algorithm
K-7	I-Algorithm
.	O
</s>
<s>
Still	O
more	O
recently	O
,	O
the	O
(	O
upper	O
)	O
mid-range	O
Nikon	B-Algorithm
D7000	O
has	O
brought	O
the	O
feature	O
to	O
a	O
somewhat	O
lower	O
price	O
point	O
.	O
</s>
<s>
Some	O
real-time	O
exposure	O
simulated	O
capable	O
live	B-Device
preview	I-Device
digital	B-Device
cameras	I-Device
also	O
offer	O
live	O
histogram	B-Algorithm
graphs	O
for	O
tonal	B-Algorithm
balance	I-Algorithm
or	O
color	B-General_Concept
,	O
where	O
the	O
graph	O
changes	O
instantaneously	O
as	O
exposure	O
adjustments	O
are	O
made	O
.	O
</s>
<s>
Almost	O
all	O
modern	O
bridge	O
and	O
compact	O
cameras	O
have	O
a	O
movie	O
mode	O
,	O
while	O
this	O
feature	O
only	O
became	O
available	O
on	O
DSLRs	B-Device
during	O
2008	O
.	O
</s>
<s>
The	O
Nikon	B-Algorithm
D90	I-Algorithm
with	O
720p	O
video	O
was	O
announced	O
in	O
August	O
2008	O
,	O
and	O
the	O
Canon	B-Algorithm
EOS	I-Algorithm
5D	I-Algorithm
Mark	I-Algorithm
II	I-Algorithm
with	O
1080p	O
video	O
was	O
announced	O
in	O
September	O
2008	O
.	O
</s>
<s>
The	O
Canon	B-Algorithm
EOS	I-Algorithm
5D	I-Algorithm
Mark	I-Algorithm
II	I-Algorithm
was	O
the	O
first	O
DSLR	B-Device
to	O
offer	O
full	O
control	O
over	O
its	O
real-time	O
exposure	O
simulation	O
live	B-Device
preview	I-Device
for	O
video	O
,	O
rather	O
than	O
just	O
autogain/framing	O
only	O
live	B-Device
preview	I-Device
.	O
</s>
<s>
Live	B-Device
preview	I-Device
can	O
show	O
additional	O
information	O
,	O
such	O
as	O
an	O
image	B-Algorithm
histogram	I-Algorithm
,	O
focal	O
ratio	O
,	O
camera	O
settings	O
,	O
battery	O
charge	O
,	O
and	O
remaining	O
storage	O
space	O
.	O
</s>
<s>
Some	O
implementations	O
have	O
a	O
focus	B-Algorithm
peaking	I-Algorithm
feature	O
that	O
highlights	O
areas	O
of	O
the	O
frame	O
that	O
are	O
in	O
focus	O
.	O
</s>
<s>
Show	O
the	O
scene	O
from	O
the	O
same	O
viewpoint	O
as	O
the	O
camera	O
lens	O
,	O
without	O
parallax	B-Device
.	O
</s>
<s>
Cope	O
with	O
high	O
zoom-ratio	O
lenses	O
,	O
without	O
needing	O
a	O
bulky	O
reflex	B-Algorithm
mirror	I-Algorithm
.	O
</s>
<s>
Live	B-Device
preview	I-Device
has	O
the	O
following	O
limitations	O
:	O
</s>
<s>
There	O
may	O
be	O
a	O
noticeable	O
lag	O
between	O
the	O
changes	O
in	O
the	O
scene	O
and	O
the	O
live	B-Device
view	I-Device
display	O
.	O
</s>
<s>
Very	O
few	O
live	B-Device
preview	I-Device
implementations	O
lack	O
automatic	O
gain	O
control	O
and	O
become	O
virtually	O
blank	O
in	O
low-light	O
conditions	O
.	O
</s>
<s>
Live	B-Device
view	I-Device
of	O
compact	O
and	O
bridge	B-Device
cameras	I-Device
with	O
smaller	O
sensors	O
may	O
be	O
difficult	O
to	O
operate	O
in	O
darker	O
environments	O
and	O
tends	O
to	O
lag	O
severely	O
.	O
</s>
<s>
Live	B-Device
preview	I-Device
has	O
been	O
in	O
use	O
with	O
bridge	B-Device
cameras	I-Device
for	O
some	O
years	O
but	O
with	O
limited	O
resolution	O
and	O
image	O
quality	O
.	O
</s>
<s>
They	O
are	O
used	O
in	O
most	O
mirrorless	B-Device
modern	O
system	O
cameras	O
(	O
e.g.	O
</s>
<s>
Panasonic	O
Micro	O
Four	O
Third	O
System	O
,	O
Sony	B-Algorithm
NEX	O
,	O
Sony	B-Algorithm
SLT	O
,	O
Nikon	B-Algorithm
V1	O
)	O
.	O
</s>
<s>
Many	O
professional	O
photographers	O
and	O
advanced	O
amateurs	O
prefer	O
DSLR	B-Device
cameras	I-Device
that	O
have	O
a	O
true	O
optical	O
through-the-lens	O
viewfinder	O
(	O
OVF	O
)	O
.	O
</s>
