<s>
A	O
motor	B-Algorithm
drive	I-Algorithm
,	O
in	O
the	O
field	O
of	O
photography	O
,	O
is	O
a	O
powered	O
film	O
transport	O
mechanism	O
.	O
</s>
<s>
Some	O
early	O
developments	O
were	O
made	O
with	O
clockwork	B-Application
drives	O
,	O
but	O
most	O
development	O
in	O
the	O
field	O
has	O
been	O
in	O
the	O
direction	O
of	O
electrically	O
driven	O
transport	O
.	O
</s>
<s>
At	O
first	O
,	O
motor	B-Algorithm
drives	I-Algorithm
were	O
external	O
units	O
that	O
attached	O
to	O
the	O
basic	O
camera	O
body	O
,	O
normally	O
beneath	O
it	O
,	O
with	O
an	O
interface	O
consisting	O
of	O
a	O
physical	O
drive	O
socket	O
and	O
some	O
electrical	O
contacts	O
to	O
signal	O
the	O
drive	O
when	O
to	O
actuate	O
.	O
</s>
<s>
Beginning	O
in	O
the	O
late	O
1970s	O
,	O
motor	B-Algorithm
drives	I-Algorithm
began	O
to	O
be	O
integrated	O
into	O
cameras	O
themselvesat	O
first	O
,	O
in	O
compact	O
cameras	O
for	O
the	O
beginner	O
market	O
,	O
and	O
by	O
the	O
1980s	O
,	O
in	O
amateur-grade	O
and	O
later	O
professional-grade	O
single	B-Algorithm
lens	I-Algorithm
reflex	I-Algorithm
cameras	I-Algorithm
.	O
</s>
<s>
By	O
the	O
1990s	O
,	O
the	O
vast	O
majority	O
of	O
35mm	O
cameras	O
had	O
integral	O
motor	B-Algorithm
drive	I-Algorithm
,	O
and	O
the	O
feature	O
found	O
its	O
way	O
into	O
some	O
medium	O
format	O
cameras	O
as	O
well	O
.	O
</s>
<s>
Motor	B-Algorithm
drives	I-Algorithm
for	O
compact	O
and	O
amateur	O
cameras	O
wind	O
slowlyshot-to-shot	O
intervals	O
of	O
approximately	O
a	O
second	O
are	O
commonplace	O
.	O
</s>
<s>
The	O
first	O
35mm	O
SLR	B-Algorithm
to	O
achieve	O
such	O
a	O
shooting	O
speed	O
was	O
Nikon	B-Algorithm
's	O
F	B-Algorithm
High	O
Speed	O
Motor	B-Algorithm
Drive	I-Algorithm
camera	O
,	O
first	O
developed	O
for	O
the	O
1971	O
Chicago	O
Photo	O
Expo	O
with	O
7	O
fps	O
.	O
</s>
<s>
To	O
enable	O
this	O
speed	O
and	O
allow	O
the	O
photographer	O
to	O
more	O
easily	O
track	O
the	O
moving	O
subject	O
,	O
this	O
camera	O
used	O
a	O
fixed	O
,	O
semi-transparent	O
pellicle	B-Algorithm
mirror	I-Algorithm
instead	O
of	O
a	O
moving	O
mirror	O
.	O
</s>
<s>
Today	O
,	O
the	O
fastest	O
professional	O
models	O
from	O
Canon	O
and	O
Nikon	B-Algorithm
achieve	O
approximately	O
ten	O
frames	O
per	O
second	O
with	O
a	O
moving	O
mirror	O
.	O
</s>
<s>
In	O
the	O
digital	B-Device
camera	I-Device
era	O
,	O
some	O
users	O
continue	O
to	O
refer	O
to	O
continuous	O
shooting	O
modes	O
as	O
"	O
motor	B-Algorithm
drive	I-Algorithm
"	O
.	O
</s>
<s>
An	O
external	O
battery	B-Algorithm
grip	I-Algorithm
is	O
occasionally	O
referred	O
to	O
as	O
a	O
motor	B-Algorithm
drive	I-Algorithm
as	O
it	O
tends	O
to	O
increase	O
the	O
frame	O
rate	O
.	O
</s>
