Evening star., 1949-04-10

!ofta again n guest O. +fse &l1FSis E.
times elusive p3ct4fe o! iase yeAg -
So Eatheg Up yoGg Gamers. y pod
and l!Sat meter and So; e4g N
the country ths PARK or even
Just as far as youF car .roas varr.
With SpI!ng IN the 81 you tGsl
cant miss
!! yo4 acre Gre 81 i3sa>r " fas1
put the camera CIT ire cloSrl
She. carlng the cold months II
will oe an excellent plAn 10 SC IN
for a bit o! spring ele&a4ns A
camera laid away ios while "A
bound 20 gather oust-ln he
bellows on the lens. and II places
where you least ra:ght expeci 70
find IL Even q oox camera Wlll
have It's quota of grit and grlme
II yours is a folcsng camera
brush all the dust OF before open.
,ng. Then take = eaInels hair
brush and clean the bellows
thoroughly Then test the bellows
for light leaks Th.s can be done
by inserting = small l.gh; oulh
such as Christmas Tree Aght
inside the camera with the bellows
fully extended Close the back as
far as the lleht wire wlu allow
and turn out all lights in the room
II q leak exists II Will be visible
as the light from within the cam
era shows through the holes
There is less danger O! having
q light leak IN q box camera. but
II you have reason to suspect one
you may test II IN the same
manner. And be sure 10 set rid
Of all dust that may have ac-
cumulated on or In the box or on
the lens.
Make certain that the shutter
Is operating properly Again, dust
Ia the worst enemy Small par
ticles. practically invisible. may
have accumulated or a larger
piece OF grit may do the damage
II the camera was stored III a
damp place. sufficient oxidation
may have taken place 20 disturb
the accurate function Of the
shutter.
II for any reason your shutter
Is not operating as II should, take
the camera 10 a competent tech
nician for repairs Even the best
OF home mechanics cannot cope
with the intricacies Of camera
shutter. And II the shutter has
slowed down or sticks during the
exposure. your entire effort and
Aim are wasted.
Rated Shutter Speed.
In connection with shutter
operation. We bring to your at
tention a point that is almost
universally overlooked by the
average amateur. This is the,
factor OF rated shutter speed VS..
actual shutter speed. Last Feb
ruary. We wrote an article on the
subject Of. the proper use OF light
meters" The next morning We
found a well deserved skin letter
from one OF our readers. Mr.. Henry
Stevens of 4439 Volta place NV,
Mr.. Stevens said. II enjoy your
articles In the Sunday Star. That
interest, prompts this expression Of
mild annoyance by your omission
OF an important factor in iranslaf-
ing the light reading OF a photo
electric meter-yesterdays article.
Il have frequently watched my
friends who are the proud pos
SCISSORS of such a meter go through
the procedure you competently
described. They measure the light
from camera position. then on the
shadow side. on the high light
side. read and calculate and in
tegrate. Say the complicated der
ivation directs an exposure OF
lIl00 second at a stop between
fs and II. nearer the IL. The
shutter is set at the l/l00 mark
and the pointer Is carefully esti-
mated TO correspond with the
meter derivation for the stop.
"Invariable ] get look OF blank
astonishment when ! ask whether
the shutter will give an exposure
of 100 second. Since the first
good photo-electric meter ap-
peared on the market, have yet
to find an amateur user OF one OF
them who has the foggiest notion
bout the relation between marked
shutter speeds and the actual per-
formance OF the shutter OF his
camera.
"A survey OF the literature on
Of shutters confirms
my own observation. Reasonably
close correspondence between the
rated and actual speed of the
general run of shutters seems to be
so rare as TO qualify as a pure
Almost as rare IL
a shutter in which the actual
shutter speeds have the same re-
lAtlOI1htiip, W @s3SkAssfs s"N
dicated by the markings: llo,
ii25. 1850. etc. =.
The result OF succession OF
related ouantitative measurements
Is not more reliable or more ac~
curate than the least exact meas
In the series. Most own
ers OF photo-electric meters to
come under my observation ap-
pear to be unaware that errors in
their shutters may likely be OF
an order OF 20o-500 per cent. par
ticularly In the range OF higher
speeds" !.
After you have made sure that
the shutter is functiontng properly
take a look at the lens This
should be carefully wiped with .
sheet OF lens tissue or very SOFT