How to pronounce 光圈 in Cantonese (5 out of 8):

主要是鏡頭,要選光圈大的鏡頭(即f數字小)
And this is mostly a lens, so you have to choose a lens with a big lens -- that's a small f-number.

Cantonese Sentence Breakdown

主要 zyu2 jiu3
mainly
si6
is
鏡頭 geng3 tau4
lens
jiu3
important
vital
to want
to ask for
will
going to (as future auxiliary)
may
must
(used in a comparison) must be
probably
if
essential points
necessary
necessity
to desire
to need
should
syun3
an alternative form for 算, to calculate
光圈 gwong1 hyun1
aperture
taai3
an alternative form for the word太, too
dik1
of
~'s (possessive particle)
(used after an attribute)
(used to form a nominal expression)
(used at the end of a declarative sentence for emphasis)
truly
really
indeed
target
to lift up
few
small
to fetch
to move
to get
to pick up
to force
zik1
namely
that is
i.e.
prompt
at once
at present
even if
prompted (by the occasion)
to approach
to come into contact
to assume (office)
to draw near
quickly
immediately
數字 sou3 zi6
number
siu2
small
tiny
few
young
insignificant
minor
humble, a modest way to address oneself
lesser
day before
a little
an euphemism for ? , to fuck
to have sex with