Photography reference
Yet another Sears Complete Photo Product booklet
Product booklet for Yet another Sears Complete Photo. 72 pages in English. Read the original PDF, download or print a copy without registration.
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- Yet another Sears Complete Photo
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- Product booklet
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- 72
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Page 3 · Read text
rr TO OUR CUSTOMERSIi
If
EVERY POSTOFFICB in every state in the united fN
I States there are families who are our customers and we -.
sulply a,rarge majority of these families with practically
everything they eat, weaf of use-everything needed for I personal use, for the home, the farm, the office or the factorv.
In_buying from us these families are saving about fifteen
million dollars annually, and this tremendous saving is {i
matched by an equai advantage in quality,-qualitv for it is the lun-IIIt
damental law of our business that must never be
sacrificed to reduce price. \Afe have the most highly per-
fected methods of. buying, making and marketing ever devised
by any business institution. we insure highesl quality and"
lowest price-by ou1 perfect control of the iourcebf supply,
reaching back to the raw materials in many lines, suppiyirig
carefully selected materials to carefully selected fictoriei
either owned or controlled by us, watching every step in the
making through the eyes of our own trained exp-erts;-puttingtIi, into the goods_everypossible improvement in quality,^ takinf
,I out ofWEtheHAVEgoods everyADOPTEDitem of EVBRYunnecessaryIDEA,cost.everv device.
I every method of proved value in order that our customers
rfiay.enjoy the best possible service. We endeavor to give
service that is even better than you might reasonably dernind.
Fair criticism of our service, our goods and oui business
methods is sincerely invited. In fbct, we are largely depend-
ent upon such criticism for the correction of eriors and the
improvement of our methods. when we receive criticism or
compiaint we not only adjust the difficulty specified, but we
investigate the. cause of the complaint and we take steps to
make a repetition of the same trouble unlikely. Our custom-
ers rightiy expect the best goods, the best service, the best
treatment; we desire to give you all these and more. We
have endeavored to make the above statements so clear that
our customers will fully understand our purposes and will feel
free to bring any faults to our attention and be assured of
prompt and satisfactory action.
, nView original page 3Page 8 · Read text
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SEARS. ROEBUCK & CO., CHICAGO,ILL.
CHAPTER I.
CAMERAS.
Essentially a camera is simply a light-tight box with a piece of
glass, called the lens, in one end and a means of supporting the sen-
sitive plate or film in the other end. Rays of light, reflected from
the object to be photographed, pass through the lens and are pro-
jected against the plate lvhere they impress upon its sensitized surface
the likeness of the object.
The box constituting a eamera may be constructed entirely of
wood or metal in a rigid manner, or it may be constructed partly of
Digitally signed by leather, cloth or rubber, in such a
mike butkus
DN: cn=mike butkus, way as to permit its being folded o=orphancameras,mike
ou=29, email=mike@butkus. into a more compact form when not
org, c=USbutkus Date: 2018.12.10 in use, and it may be fitted with
14:05:17 -05'00'
various adjustments and accessories ;
but no matter how complicated the
carnera may appear at first sight, a
slight examination will demonstrate
the fact that essentially it it_gl13p]E
*ith a lens in one Lig!!;!jg!!-@:
end and a means for holding the
dry plate or film in the opposite end.
A11cameras maY be divided into
THE coNLEYSENI0R' A Box cAmERA. four general classes, the simple hand
3ameras, frequently called Box Cameras, th" @
Vis\ r Cameras and Portrait Cameras. There is an infinite variety of
ffi @, but they can all be classified "ta under one or the other of the above heads.
In taking up for consideration these different forms of cameras,
it n'ill be impossible for us to touch upon the details of manipula-
tion, such as the operation of shutters, methods of adjusting, etc.,
as these details vary in different makes and, moreover, small instruc-
tion s'heets covering these particular points are always, s€nt with each
camera.View original page 8Page 9 · Read text
I!p
coMpLETE"rNsrRUcrroNS rN pnotobRApHy. W
The simple Hand Camera or Box Camera is by far the
BOX F&;-- most popular and most universally used of all cameras. This &
Uamefas is ondoubtedly due, firsti to its simplicity of operation, and
. secondly, to the low price at which such cameras can be purchased.
Although a box camera is capable of producing fine pictures l within certain limits, there are many kinds of lvork beyond its
capacity, and many pictures which cannot be made at all with a IF
box camera are easily made with a camera more complete in its i
adjustments.
There are two principal forms of box cameras, known as plate
holder cameras and magazine cameras. In the plateholder camera
the sensitive dry plate upon which the picture is made -withis placed
in rvhat is known as a plate holder, and this plate holder, the
plate in it, is inserted in the back of the camera when a picture is
to be made. -Each plate holder holds two plates, and the plates
must be put into the holder in the dark room.
The Magazir'e Carn-
era is so constructed that
a large number of plates,
usually tlvelve, can be
put directly into the
camera itself and ex-
posed, one after the other,
thus doing away rvith
the use of plate holders.
:The most popular
and undoubtedly the
best magazine camera is
the Conley Magazirte,
andour illustration shows
the manner in which the
plates are' held a n d
manipulated inside the CONLEY MACAZINE CAMERA, SHOWINC
camera. INTERIOR ARRANCEMENT.
A Box Camera is about the best instrument for a beginner
wh6 desires a simple, 1ret good camera at a very small expensei Box
cameras are usually provided with universal or set focus lenses, that is,
lenses not requiring to be focused and therefore mounted immovably in F the camera front. Such cameras offer special advantages to the begin-
ner, or to those who do not rvish to go too deeply into photcigraphy, . 4
as it is not necessary to adjust the focus each time a picture is taken.View original page 9Page 10 · Read text
www.butkus.us
SEARS, ROEBUCK & CO., CHICAGO, ILL'.
The Folding Hand Camera is the next step Folding Iland consists essentially Box Camera, andabove the of Cameras and a rear part part supporting the lensa front
with adjustment for holding the sensitized plate in position, these two
parts being connected by a rubber or leather bellou's, which folds like
an accordion, making it possible to fold the carnera into smaller space
for convenience when not in use. The principal and most important
advantage of the folding hand camera lies in the fact that the distance
betrneen the plate and the lensmaybe altered at will; in otherwords,
the camera may be focused.
T h e s i m p l e s t
form of Folding Hand
Camera is provided
with no special ad-
justmentsorimprove-
ments and, therefore,
the fact that it can
be focused and folded
to a more compact
form constitutes its
only advantages over
the plain Box Cam-
era.
fn the
more com-
plete folding
c a m e r a s ,
however, is CONLEY A FOLDINq CAMERA.
reached the
highest degree of perfection attained in the making of cameras, and
some of the latest-styles, completer rvith all the most improved
adiustments are marvels of mechanical perfection and capalle of the
difhcult rvork.
\\re reproduce an illustration of the Conley A Folding Camera,
which is an excellent example of the Folding Hand Camera, and'ithich,
although not as complete in its adjustments as some of the more ex-
pensive cameras, is thoroughly well made throqghout and fgly meets
the requirements of the vast majority of amateur photographers.
Ttre highes- types of Folding Hand Cameras, complete in every detail
and adjustment (some of which are not used once in a hundred
exposures), might very properly be called photographic luxuries.View original page 10Page 11 · Read text
10 CONLEY'S MANUALJ OF PItrOTOGRAPHY.
The Fold-
i n g H a n d
Cameras a r e
designed to
be used either
with or with-
out a tripod,
and are suit-
able for any
class of work
which may be
done either with a simple
Box Camera ot a complete
Professional View Camera.
C a m e r a s d e -
VieW signed for use only
t'i.th. * tripod are A VIEW CAi!'iERA Camefas '
called View Cameras
and are almost alu'ays em-
ployed by professional pho-
tographers. Although they
do no better work than a
good Folding Hand Camera,
they are more strongly and
substantially constructed;
convenience in operating,
together r,vith strength and
durability, being the points
kept most prominently
in vierv by the manu-
facturers, rather than
mere elegance of finish
or compbctness.
The best example of
a thoroughly well made,
substantial, service-
able View Camera
is the Queen City
shown in our illus-
tration. A camera
like this one can be
LView original page 11Page 12 · Read text
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SEARS, ROEBUCK & CO., CHICAGO, ILL. l l
used for any kind of work which either an amateur or professional
photographer would ever have occasion to do.
We cannot too strongly recommend the View Camera to both
amateur and professional for general photographic work. It combines
ease of operation, completeness of adjustment, strength and dura-
bility to a degree not reached in other styles of cameras. The bellorvs
is made amply long, the swings possess great latitude, the front has
a u'ide range of movement, all adjustments are easy to get at, and
therefore convenient to manipulate. The style of construction per-
mits the use of extreme rvide angle lenses, or any kind of rapid recti-
linear or anastigmat lenses, even the largest sizes, and the ample size
and strength of the front even pernits the use of the smaller types
of portrait lenses. In a View Camera nothing that will add to its
convenience of operation, its accuracy and ease of adjustment, in short,
to its efiectiveness as a picture taking machine, is- sacrificed for mere
elegance of appearance or compactness.
A View Camera is a businesslike camera for real photographers
who are seriously interested in their rn'ork and who want an outfit
that is, above all other considerations, thoroughly practical in every
detail.
Portraits can be made with either a regular View
Camera or Folding Hand Camera, and in a limited way POftfait
even with a simple Box Camera, but the camera d"tigtrgd CamgfaS
especially {or jlhe purpglsr has points of superiorityffi-is
particular work, and in photographic studios or galleries regular
Portrait Cameras are usually employed. As these cameras are designed
only to be used in studios, no attempt at reducing them in size or
weight is made, so they are always large and heavy, and must be
supported on what is known as a camera stand, a device so arranged
that the camera may be quickly raised, lowered or tilted to any
desired angle, and for convenience in moving the instrument about
the gallery, the stand is usually furnished rn'ith small r,vheels or casters.
As before stated, however, just as good portraits can be made
with a View Camera as with a Portrait Camera. It is merely a
question of convenience in working, and many professional photog-
raphers who do both portrait work and outside work and who do not
care to invest in trn'o cameras use a \rier,v Camera for both pur-
poses. While the View Camera readily adapts itself to either
line of work, the Portrait Camera, or'ving to its size and x'eight, is
suita'ble for use onlv in the studio.View original page 12Page 13 · Read text
"IN. 12 COMPLET]ETNSTRUCTIONS PHOtOGN,{PNV.
CHAPTER II.
LENSES AND STIUTTERS.r As previously explained, the lens is the piece of glass in the
front of the camera and is the most expensive and the ry:!.igporta!1ft of the outfit. The quality of rvork done with a camera depends EI!
entirely upon the lens, and therefoie, in selecting your outfit care
should be exercised to secure one containing a good lens. As the
quality of the lens cannot be judged in any way by its appearance,
and as a bggl4ner in photography is entirely incapable of judging
a lens, everr by an actual trial, it is usually necessary to take the
dealer's word regarding this lloint and thus the advisability of dealing
with a house whose goods are known to be exactly as represented is
apparent.
Photographic lenses may be divided into five general classes,
single lenses, double or rapid rectilinear lenses, anastigmat lenses,
wide angle lenses and portrait lenses.
The cheapest photographic lens made is
NOn-AChfOmatiC a singie convex lens, just like a . common mag-
nifying glass or like the lenses in spectaclcs which Single LenSeS
very old people wear. Such lenses are used only in
the very cheapest cameras and as they are not accttrately ground and
not properly corrected, they distort the picture, and as they are not
achromatic they separate the rays of light into colors, thus blurrfu
the picture.
The si'g@
Achromatic
Single Lenses sirnple lenses'one double
convex, the other plano
convex, cemented together, thus apparently
forming a single lens. Such a lens does not
separate the rays of light into colors and will
therefore form a sharp, clear picture. Such
cameras as the Conley Sr. Bor, or the Conley LENSSINCLEWITTIACHROMATICREVOLVINO
. Magazine Camera are prcvided with single DIAPHRACM.
achromatic lenses.
LView original page 13Page 14 · Read text
.ROEBUCK'& www.butkus.us "SEARS: CO.;'CHICAGO;ILL. 13
A Rapid Rectilinear Lens, u'hich is a doubl" Rapid ReCtilineaf
lens, consists of two single achromatic lenses 'I'hey LenSgS
mounted in opposite ends of a brass tube.
are called rectilinea,r be-
cause they render the
straight lines of a picture
without distortion, the
word rectilinear being
derived from the Latin
words for straight and
line.
A rapid reetilinear
l e n s , a s a l r e a d Y e x -
plained, consists reallY
of two lenses. which are
spoken of as'ncombina-
tions, " the lens in the
front of the tube being
known as the " frotlt
THE CONLEY F.8 RAPID RECTILINEAR LENS. combination, " the other
as the "rear combination. " The better grades of rectilinea.r lenses
afe so designed and constructed that the separate cornbinations may
be used alone, which is a desirable quality, as the single combina-
tions possess a much greater focal length than the complete lens, and
the efficiency of a photographic outfit is much increased by having
available lenses of different focal lengths.
Each combination of a double lens consists of two or more
pieces of glass which are firm1y cemented together rvith an invis-ble
cement (balsam), thus apparently forming a single lens'
In a general way, rapid rectilinear lenses are divided into t$'o
n'symmetrical" and "Convertible' " A Symmetrical lenS is Classes,
one in rn,hich the front and rear comtrinations are of thc same stvlc
of construction and the same focal length; in other worcis, the front
combination and rear combination are exactly alike, an'J it is from
this fact that the lenses are spoken of as symmetrical. In a symmet-
rical lens the single combinations usually have a focal length of aborrt
double that of the complete lens.
Convertible lenses are lenses in which the front and rear combi-
nations are of different construction and ccrnsequently of different
focal lengths, and with a convertible lens thc user has at his com-
manrl three different focal lengths, namely, the complete lens, theView original page 14Page 15 · Read text
r
14 COMPLETE INSTRUCTIONS IN PHOTOGRAP}IY.
front combination alone, and the rear combination alone. Of course,
in different lenses the relative focal lengths differ, but taking the
lens furnished with the Conley Double Bxtension Camera in the 5x7
size, u'e have an example of a rectilinear lens of the convertible type
in rvhich the focus of the front cornbination is 18 inches, the rear
corabination, 14 inches, and the complete lens, 8 inches.
Next to an anastigmat lens a good rapid rectilinear lens of the
symmetrical or convertible type is the best lens to use for general
all arround photographic work.
Wide Angle Lenses are much the same as recti-
\ilidg Angle finear lenses in general construction, but the two
combinations are mounted more closely together and for LgnSgS
this reason a wide angle lens is capable of including a
much wider extent of view, hence the name wg!gg}3.
These lenses are not very suitable for land-
scape or outside view rvork, although in certain
cases, such as the photographing of buildings,
s'here it is impossible to get far enough away to
include the whole of the building with a recti-
linear lens, the wide angle lens becomes a
necesslty. iloNARCH WIDE
Wide angle lenses are especially desirable ANGLELENS'
for photographing interiors; in fact, they are practically indispens-
able for this work, as a single achromatic or rapid rectilinear lens
does not include a sufficiently wide angle of view to make a good
interior'
Anastigmat Lenses represent the highest degree of
AnaStigmat perfection in lenses and possess points of superiority over
the rapid rectilinear lenses rvhich make thenr very LenSeS
desirable. As compared rvith rapid rectilinear lenses,
. the anastigmat lenses possess greater specd, better definition, and
entire freedom from astigrnatism. Definition is that property of a
lens which enables it to make sharp, clean cut pictures, and while
fine definition may be obtained rvith an ordinarv rectilinear lens by
.using a small diaphragm, which, :of cottrse, necessitates a longer
exposure, the anastigmat lens will give good definition even u'ith the
full opening. Anastigmat lenses are suitable for all kinds of photog-
raphy and may be described as "universal" lenses, as they are
adapted to landscape rvork, architectural subjects, interiors, groups,
portraits and copying. The large working aperture makes them
particularly suitable for very.rapid instantaneous exposures and forView original page 15Page 16 · Read text
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SEARS. ROEBUCK & CO., CHICAGO, ILL. t5
portrait work. A few years ago anastigmat lenses could only be
purchased at very high prices, placing them beyond the reach of
many photographers, but during the last few years these lenses have
not only been still further improved.in quality, but the competition
between different manufacturers has gradually brought the prices
lower and lorver until now it is possible to purchase a strictly high
grade genuine anastigmat lens rn'ith an effective apertufe as great as
F.6.8 at prices for the 4x5 and 5x7 sizes ranging from $20.00 to
$35.00, including shutter. Lenses of this style and quality a few
years ago could not be purchased for less than $50.00 to $75.00. The
modern anastigmat lens is in every way a triumph of optical and
rnechanical skill.
Portrait Lenses are also very similar in construction to
r e c t i l i n e a r l e n s e s , b u t a r e s o m a d e . t h a t t h e y a r e . @ Portrait
that is, they require very short exposures. Portrait lenses Lenses
usually have a long length of focus in proportion to the size
of the plate and the great rapidity with which they work makes
them especially suitable for making portraits.
Portrait lenses are not to be recom-
mended for anything except actual portrait
work indoors. As before stated, all other
good quaiities are sacrificed in order to
obtain great speed and they are not very
rectilinear and do not possess much depth
of focus. 'Good portraits can be made
A with rapid rectilinear or even with single
achromatic lenses, the only disadvantage being that a slightly longer
exposure must be given than would be necessary with a regular
portrait lens. 'a
The focal length of lehs is the distance from the
ground glass to the optical center of the lens when FOCaI Length
focused on some distant object. The greater the Of LenSeS
focal length, the narrower becomes the angle of view,
hence the single lens, which usually embraces a narrow angle of
view, has a long focal length, and the wide angle lens, which
embraces a large extent of view, has a very short focal length.
when the focal length of a double lens is mentioned, it is aft,vays
understood, unless otherrvise specified, to be the equivalent focus, by
which is meant the distance from the optical center of the lens to
the ground glass when it is focused on a distant object. The optical
center of the lens is not usually the same as the actual or mechanicalView original page 16Page 17 · Read text
v
16 COMPLETE INSTRUCTIONS IN PHOTOGRAPHY.
. centcr except rvith simple convex single lenses; hence, the term
"equivalent " focus as applied to double lenses, meaning that the lens
has a focal length equivalent to that of a single lens which would
p r o J t r c e o n t h e g . o o i @ ' . i m a g e o f a g i v e n o b j e c t a t a g i v e n
distance exactly the same size as rvould the double lens. In the case
c,f portrait lenses, rn'hich are very large and bulky, the back focus
is often stated so that purchasers can readily tell rvhether the camera
on which the lens is to be used has sufficient bellorvs capacity to
accommodate the 1ens. The back focus is the distance from the back
of the lens to the ground glass when focused on a distant object.
The Diaphragm or Stop is the means of regulating the
,Diaphfagmsorstops amount of light rvhich passes through the lens during il."""ff;ln".YJxtl1"'lJi:"T$#:'"";'"f:,1i;i.:,?'
. number of holes of different sizes in it, so placed that any one of
these holes or openings may be revolved to the center of the lens
and the size of the opening regulates the amount of light aclmitted.
Such stops are known as revolving diaphragms, because they are
revolved to bring the desired opening into position.
Rectilinear lenses of the old style were usually provided with a
set of loose diaphragms or stops, that is, separate pieces of metal,
each with a hole in the center, which rvere inserted in a slot in the
lens tube. Loose diaphragms are knorvn as Waterhouse .diaphragms.
Another style, known as the Iris diaphragm, is an ingenious
device of thin metal or hard rubber leaves inside the lens tube, so
arranged that a round opening is left in the center, the size of rvhich
can be varied as clesired by turning a lever on the outside. The
Iris diaphragm is, of course, the most convenient and satisfactory
style, as there are no loose pieces to lose or mislay, and it can be
instantly adjusted to any desired size The effects produced by the
different styles of diaphragms, Revolving, Waterhouse or Iris, are,
of course, identical, and the only differences are matters of conven-
ience in operating or elegance of design and finish
The use of diaphragms can best be illustrated by
USgDiaphrasmsOf il-:Jf:#::l J1"",,11T";i"i3,,.:?*"J':1"# upon some object about 20 or "j#25 feet arvay. Upon carefully observing
the image upon the ground g1ass, you will note that objects qgit",
c l o s e t o t @ a n d p r o b a b 1 y , a 1 s o , o t l j e c t s a t a c o n s i d e r a b 1 e
@lurred,that is,not sharpty roffi
a *;he-r r*.Tl stop in the lens and probably tire first thing you will
; iIView original page 17Page 18 · Read text
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SEARS. ROEBUCK & CO., CHICAGO. ILL. L7
observe is that the image is not nearly as ildgE! as it was. There
is less light coming through the lens. But look closer and you will
find another change: those portions of the view that were before
out of focus or fuzzy are now sharp and distinct.
A little experimenting here will show you that the smaller the
+'" stop is, the sharper, clearer and rnore distinct the picture is, and this
may lead you to ask, why not use the smallest stop a1l the time? In
reply, we wilt call your attention to the fact that the image, although
sharp, grows correspondingly darker and dimmer as the stop is made
smaller, and as it requires a certain invariable amount 9f actiqn.by
light in order to produce the pictute, y".t catt t"adily understand that
iEismaller the stop is, the.lqggr the exposure mtist be. It therefore
b""ofrF!?actically i-po.ET{ except under very unusual con-
ditions to make a snap shot or instantaneous exposure with a small
stop or diaphragm.
The size or diameter of the stop is usually desig- SiZe Of
nated by its relation to the focal length of the lens. Diaphfagms^ For example, if the loca1 length of the lens is 8 inches
and the diameter of the largest stop is 1 inch, the focal length divided
by the diameter of the stop gives us eight and the stop is called F.8;
+.l: F.thestanclingnext sizefor isfocaiF.11,length.that is, Inequala lensin havingdiametertheto largestone-eleventhstop F'8,of
. t . the focal length, and the next size is F.16, etc.r8i
f':' There is another systern of designating the stops, known as the
U. S. system, in rvhich a stop equal in value to F.8 is called No' 4'
F.11 equals No. 8, etc.
The following table gives the relative values of the F. system
and the U. S. systemof making stops:
F.4 equals - - - No. L F.22 equals - - N o . 3 2
F.5.6 equals - No. 2 F.32 equais - No. 64
F.8 equals - - -' No. 4 F.45 equals - - No. 128
'$ F.l t t,quals - No. 8 F.64 equals - No. 256
F.l6 equals - - - No. 16
The size of each successive stop is such that it wirl require just
twice as long an exposure as the one preceding it; for example, if for
the No. 4 stop the correct exposure is 2 seconds, the No. 8 will require
4 seconds;No. 16, 8 seconds;No. 32, 16 seconds;No. 64,32 seconds;
No. 128, 64 seconds,etc.
A knowledge of the values of the different stops and their rela-
tion to each other is necessary in deterrnining correct exposures
and should be carefully studied by anyone using a carnera.
. l * " - t a . i ! r & * . t d , . , -View original page 18Page 19 · Read text
rtl COMPLETE INSTRUCTIONS IN PHOTOGRAPHY.
Depth ,Of The experiment of focusing on a certain otrject
wilh the largest diaphragm in the lens and finding other FO|US
objects which are closer to or farther from the camera,
out of focus, will also illustrate another qualification of lenses, kno.wn
as depth of focus, or the extent to which both near and far objects
can be brought into focus sharply at the same time.
Depth of focus depends entirely on the size of the diaphragm and
the focal length of the lens. The smaller the diaphragm is, the
greater will be the depth of focus, and the shorter the focal length of
the lens is, the greater the depth of focus will be. conversely, theF larger the diaphragm or the longer the focal length, the less depth of
focus the lens will possess. An increase in the focal length or in the
size of the diaphragm is necessarily accompanied by a corresponding
decrease in the depth of focus. Lenses, even of entirely difierent
styles of construction, always possess depth of focus to exactly the
same extent if they are of the same focal length when used with
stops of the same size. For instance, if we take an ordinary raprd.
rectilinear iens with a focal length of 8 inches and make a nega-
tive with it, using, for example, stop F.82, and at the same time we
make another negative with a fine anastigmat lens of 8 inches
focal length, again using stop F.32, both negatives will show
depth of focus to exactly the same extent. If we take two lenses of
unequal focal lengths and use them both with stops of the same
value, say for example, F.16, the lens having the shorter focal length
will show the greatest depth of focus. rf we take two lenses of the ;' s. l
. same focal length and use one with a large stop and the other rvith a
small stop, the picture made with the small stop will show the great-
est depth of focus.
Depth of focus, which is the capacity of a lens to give sharp
images of objects situated at different distances from the camera,
must not be confused with definition. Depth of focus depends
only on focal length and size of stop, and is the same with al1 lenses
where these two factors are the same. Definition, which is the ability
of a lens to produce sharp, clear, crisp detail, is a test of quality ano
is possessed to a much greater degree by fine lenses than by cheap
lenses. The finest definition is yielded by the modern anastigmat
lenses. Rapid rectilinear lenses give good definition, but not as good
as does the anastigmat lens.
From consideration of the foregoing statements, it is apparent
that any increase in the working aperture of a lens must necessarily
be accompanied by a corresponding decrease in depth of focus, or, in
L.,.*,View original page 19Page 20 · Read text
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SE"ARS,ROEBUCK & CO., CHICAGO, ILL. lg
t other tord., the larger the stop, the less the depth of focus will be.
r It is also evident that great depth of focus is easily obtained vgith
any lens by using a very small diaphragm; but this, as explained in
; the next paragraph regarding speed of lenses, means a corresponding
; increase in the length of exposure.
rt must also be borne in mind that great depth of focus is not
always desirable. For example, r'r'hen photographing a group, it is
much better if the background is not sharp. only the figure. tt
selves in the group should be in sharp focus, and the backgrouncl "*-and
other non-essential details should be made as inconspicuous as pos-
sible by having them out of focus. Many randscape pictures are
much more artistic if only the important or interesting portion of the
picture is sharply defined, and other parts, possibly the extreme
distance, are slightly out of focus, thus giving greater prorninence to,
and emphasizing the essential or important parts of the picture.
The length of exposure, light and other condibions The Speed being equal, depends entirely upon the size of the of Lenses opening in the lens as compared. x'ith the focal length,
and this naturally brings qs to the consideration of one of the most
important qualifications of a lens, viz., jts speed or rapidity. rt will
b e r e a d i 1 y u n d e r s t o o d t h a t t h e 1 e n s * ' l @ g i n p r o .
portion to its focal length n'ill be the most rapid, that is, will rnake
pictures u'ith the shortest exposures, and speed is a very desirable
feature. The largest opening, sometimes called the aperture, of a
single achromatic lens is usually from F.12 to F.15, rnhile a good
double or rectilinear lens usually has its largest opening aboutb.g;
so it is \zery apparent that a rectilinear lens is much faster, that is,
requires much shorter exposure than a single lens. To put it into
plain figures, a lens n'orking at F.8 will require less than one-third as
long an exposure as one rn'orking at F.15, all other conditions being
equal' This, of course, applies only when working rvith the la.gesi
stop. If both lenses are stopped dorn'n to the same size op"rrirrg,
say F.32, for exarnple, then the same exposure is required with each.
The largest opening of a wide angie lens is usually about F.15,
and sometimes as small as F.22; so wide angle lenses are necessarily
slow.
Anastigmat lenses are much faster than rectilinear lenses, the
most popular ty-pes usually rn'orking at F.6.8, which makes them about
30 per cent faster than the ordinarv rectilinear lens working at F.g.
In actual practice they mak" u,r, better showing than this as
"rr"r,
. .fj
,-r:{*...View original page 20Page 21 · Read text
20 CoMPLETE INSTRUCTIoNS IN pgoTo,cRAPIIY.
compared with rectilinear lenses, because, owing to their better defin-
ing power and flatter field, they can be used at full aperture in casesI u'here the rectilinear lens would be still further stopped down.
Portrait lenses are the fastest oi all lenses, all other qualities
being sacrificed for the sake of speed,andusually work at from F.B1r5
to F.5rl, rvhich is from trvo to six times as fast as rectilinear lenses,
from ten to fifteen times as fast as single achromatic lenses, and
fully twenty times as rapid as the average u,ide angle lens.
speed in a lens is especially important when making snap shot
or instantaneous exposures, as the extreme shortness of the exposure
must be made up or compensated for by an ability to admit a large
volume of light, owing to the short time in which the light is allowed
to act upon the plate.
Bearing in mind the extremely short time in which light is
allowed to act upon the plate in an instantaneous or snap shot exposure
(only a small fraction of a second), and remembering that a certain
amount of action bl4ght is absolutely necessary in orde. to ffi
@, the necessity of using a rapid lens, that is,
one with a large opening, thus admitting lots of light, will be apparent.
The fact that a shorter exposure is necessary with a lens which u,i-it"
a large volume of light may be illustrated in a crurle way by the
operation of filling a vessel with water through a pipe. The vessel
can be filled entirely ful1 rvith a small pipe, but it will take a much
longer time to do it than rvould be required with a rarge pipe. In
other woris, the pressure of water being the same, the larger pipe
will fill the vessel much more quickly than the smaller pipe. rrrthe
same way a picture can be made in a very much shorter time nith a
lens having a large aperture than it can with a lens having a smaller
aperture.
Single achromatic lenses are rapid enough for ordinary snap
shot rvork rn'hen the light is brilliant, but a double or rectilinear lens
is, of course, better, and there are many occasions when the light
is not quite bright enough to make a good snap shot u'ith an achromatic
le--:.s and yet bright enough to make good negatives u,ith a recti-
linear lens. The still greater rapidity of the anastigmat lens makes it
possible to secure fully timed negatives on dark,cloudy days rvhen snap.
shots would be impossible, even rvith the best rapid rectililear lenses.
\Yith a wide angle lens snap shots can only be made under the
most favorable circumstances. In spite of the fact that the rvicie
angle lens is slow, it is a very valuable addition to an outfit, beingView original page 21Page 22 · Read text
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especiatiy suited to photographing interiors. As time exposures
must be rnade arlyway, when photographing interiors,'the slowness
of the wicle angle lens is no disadvantage, and the wide extent of the
view embraced is a great aFantage, as single achromatic and rectilinear
lenses do not embrace a wide enough angle to show all that is usually
desired in an interior view., owing, however, to the wide angle
embraced, these lenses, to a certain extent, distort and spoil the
perspective of the view.
In the. preceding paragraphs we have ex- ACtUal Diaphfagm
plained that the speed of a lens depends.upon ValUeS
the size of the aperture as compared wrth the
focal length, but we cannot measure th" g1*lis aperture and focal
length directly with a rule except in the case of simple lenses, consist-
ing of only one piece of glass or one combination. With a perfectly
sirnple convex single lens we will assume that the diameter of the
l:rrgest stop or diap\ragm is 1 inch and that, when the camera is
focused on some .r"ry dirt.nt object, the distance from the optical
center of tire lens to the ground glass is 16 inches. We then say that
the value of the largest stop, that is, the full aperture of the lens, is
F.16; in other words, the diameter of full aperture is equal to one-
sixteenth of the focal length and, therefore, this lens is said to have a
speed of F.16.
Now, this same principle holds true when we come to double
lenses of the rectilinear, wide angle, anastigmat and porrrait types,
but with double lenses the F. value of the opening cannot be deter-
mined correctly by direct measurement with a rule in inches or frac-
tions of an inch. To appreciate this fact, we must rernember that
the speed of a double lens depends upon the amount or volume of
light which it transmits. A single lens transmits a volume of light
ffiTly to th" di"pht"gttt itt dia*"tet, but a double lens trans-
"q,l"l mit" of tight that is actually greater in 4iameter than the
" ""lt*e through which it passes. This is due to the fact that the diaphragm
;ys-Alight, as they enter the lens, are refracted, causing them to
converge, and the diaphragm, which is located between the front and
rear combinations of the lens, allows ag of light to pass through,
rvhich, before its refraction, was greater in diameter than the
diaphragm itself.
With single lenses the diaphragm is placed in front of the lens
and only the actual volume of light which passes through the
diaphragm can. be transmitted by the lens, but in double lenses the
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22 COMPLETE INSTRUCTIONS IN PHOTOGRAPHY.
. diaphragm is placed inside the lens between the front and rear
gombirlatioris, rta tn"
trrst, rvhich by refraction converges it before it reaches the diaphragm
and enables it to pass through an opening of ress than iis own .original diameter.
Now, to determine the speed of a lens, we must have these two
factors: first, the exact equivalent focus of the rens; second, not the
exact diarneter @ut ttr" diameter of the cone "t oJ liglt which it rvill transmjl The
"qoirru,1"ffi enter of the lens to the ground glass
when the lens is focused upon a distant object. with si"mpre l"'rr."s
we can measure this directly vvith a rule, because the optical center
and the mechanical center coincide, but in a double lens- the optical
center and the mechanicar center do not, as a rule, coincide, and
while the actual opticar center can be determined by a complicated
mathematical computation, it is unnecessary to do so, as there is an
easy and simple way to dete'nine the equivalent focus of a double
lens and also the actual F. value of the tpening, which we will now
e-rplain.
. To measure the speed of a double lens, in other
To Measure the words, to determine the true F.value of the rargesr
Speed of LenSeS opening, we proceed as follows: ftg!., focus ,".y
andmark.,,h"T:T*';Ji#:HT:Iff ffi*:'H,""fff: bellows is extended; second, focus on some small article at a distance
rvhich will enable you to mike the image on the grouncr glass exactly
the same size as the obiect itserf, and perfectry sharp, with furl
aperture. A strip of white paper or a rure forms a handy object for
this purpose, and great care must be exercised to make the image on
the ground glass absorutely the same size as the object itserf ,rrjp"r-
fectly sharp. Now, again, mark on the bed of the camera the piirrt
to which the bellon's is extended, and. the distance between this point
and the point to which it u'as extended previously when fo"use^d or,
the distant object, is the exact equivaleni focus of the rens.
rt wil readily be understood that this work requires a rong
bellows camera, such as the No. 1 conrey vier,v, or the conley Double
Extension camera, and to insure accuracy in marking the poirrts to
which the berlo'r's is extended, some point on the bed of th! camera
must be selected where a small mark or scratch can be made on the
movable portion to exactry coincide with the immovable part. Then
tl- -"" -- -..View original page 23Page 24 · Read text
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SEARS, ROEBUCK & CO., CHICAGO' ILL. 23
when the bellows is extended and the second mark made, the exact
measurement between the trvo marks is easily secured'
Third. make a small round hole with a needie exactly in the
."r,tfrTihe septum of your plate holder, and put the holder into
the back of the camefa, the same as when making an exposure, but
rvithout the slides in and remove the ground glass. Extend the
camera and clamp it tightly at the point where it is in focus on a
very distant object (this point being already marked on the camefa
bed), and see that the camera front is so adjusted that the lens is
exactly opposite the hole in the septum of the holder, that is, exactly
centered. Now take the camera into the dark room' place a bright
light right back of the hole in the septum a"d @
the diameter of the circle of light *hi"h *ill be se"
if."-fe the lens, obtained as above
dr aivided by the diameter of the circle of light gives the exact
F. value of the openlng.
This circle of light may also be measured by placing the back of
the camera opposite a bright window and covering the front end of
the camera with a focus cloth, the same as when taking a picture,
the circle of light being visible only when all other light is cut ofi so
far as possible, the same as when viewing the image on the ground
g1ass.
Example: Suppose that by the method just described we find
the equivaient focus of a lens to be gfuifr:dnes and the circle of iight
on the front of the lens 1 /s inc:nes in diameter with full opening'
g94 divided by 1ft eqtals 7; hence, the speed of the lens is F.7.- As
another example, suppose the equivalent focus is 8rl inches and the
circle of light tr/a iiches in diameter. 8rl divided by lrl equals
6 4-5, or written decimally, as is customary, 6.8; that is, the speed or
full working aperture of the lens is said to be F'6 8'
Purchasers of fine anastigmat lenses are sometimes
unnecessarily alarmed by finding a number of small air Aif BUbbleS
]. bubbles in the glass, but these bubbles should occasion no in LenSeS
misapprehension, as they do no harm whatever'
In the manufacture of anastigmat lenses, very special qualities
,r& of lena glass are used, varieties of glass which difier widely in opticalr o,rltiti"Jrnd chemical composition from the ordinary flint and crown
gi.r.". used in the construction of cheaper lenses. The manufacture
if th"r" special grades of Jena lens glass is attended with great tech-
nical difficulties, and it has been found practically impossible to pro-
{l duce glass of the 'equired qualities entirely free from small air
J: ri:I.l! -.i^iiiii,&&i&i. -",View original page 24Page 25 · Read text
I
; 24 coN{pLETE TNSTRUCTTONS pHoTOcRApHy. IN
bubbles, but as these air bubbles have no influence upon the optical
qualities of the rens, they are not regarded as faults.
rn considering the matter of bubbles in lenses, we must bear in
mind these facts: first, in making anastigmat lenses it is absolutely
necessary to use these special and peculiar grades of lens glass;
second, these special varieties of glass always contain at least a few
small air bubbres; third, these trubbles have no practicar efiect upon '
the working quality of the lens. From a consideration of these three
facts, it is evident that the presence of air bubbles in a lens is of no
importance'whatever and may be entirely ignored by the user of the lens. (
rn the manufacture of ordinary rapid rectilinear renses, singre
achromatic lenses, wide ang,re" lenses, etc., it .is possibre to .use the
commoner varieties of crown and flint optical g1".., the making of
which is a more simple matter than the- production of the special
glass for anastigmat lenses, and no difficulty is found in producing
these cheaper glasses without bubbles.
while occasional pieces of the speciai Jena lens glass are found
free from bubbles, such pieces are rare, and a comprlte rens entirely
- free from air bubbles (if sold as an anastigmat lens) might well be
regarded with suspicion, as complete freedom frorn bub-bles would
indicate tbat a cheaper glass hacl been used in its construction and
that it was not a genuine anastigmat lens.
It is an excellent plan to have more than one
Kind of Lens lens, but if you are limited. to one, let it be an anas_
to Purchasg tigmat, unless such a lens costs more than you care to
invest, in which event a good rapid rectilinear should
be selected. A wide angle lens makes d, very,rvaluable adrlition to an
outfit, but is, of course, suitable for only certain ancl,
although it will enable you to make many pictures "l"rsfrffirk,which your regular
' lens would not make in a satisfactory ,r,."rlrr"r, it courd not be de-
pended upon for all around u'ork.
Portrait lenses, being suitable only for portrait work, are selclom
used by any but professional photographers, and then only in the studio.
Thg The shutter is the mechanism or devica, by means of
which the bpening to admit right through the lens is opened Shutter
or closed in making arL exposure. There is arL irinnite
variety of shutters on the market, almost every manufacturer having '
a different style, but the object attained in all cases is the same;
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FI SEARS; ROEBUCK & CO.,"CHICAGO,ILL.'" 7 \
simply a device for admitting light through the lens to rnake the
exposure.
The shutters on simple hand cameras are usualry operated by I
pushing a button, and on the folding hand cameras the same result
is obtained by the more convenient method of squeezing a rubber
bulb. A shutter operated by a bulb is said to have pneumatic release,kt and this method of operating the shutter is not only very convenient
in all cases, but is particularly desirable when making time exposures,
as the danger of spoiling the picture by jarring the camera is avoided.
The Conley Automatic Shutter,
which we show in our illustration,is one
of the latest and most complete shut-
ters now made, being provided with
Iris diaphragms and giving, with
one pressure of the bulb, automatic
exposures of from 1-100th of a second
to a full second, or, by two pressures,
time exposures of any desired length.
The shutter of an ordinary hand
camera should be as simple in con-
struction as possible, to avoid the
coNLEy AUTomATrc SHUTTER. danger of becoming out of order,
and should be arranged to give either time or instantaneous expos-
ures, and, if possible, should be automatic to the extent of resetting
itself after each exposure, so that it will always be ready for business.
Shutters are rather delicate pieces of apparatus, and
must be handled with due care. Even the very best of them, Cafe Of
owing to the more or less complicated mechanism and the ShUttefS
delicacy of the various adjustments, is liable to become
out of order. when a shutter gets out of order it is almost invar-
iably best to return it immediately to the maker u'ithout attempting
any repair work on jt. Even a good mechanic, unless he has had
actual experience in the repairing of shutters, is very apt to do one
of these instruments more harm than good.
Never put oil on any part of the shutter. At first thought it
may seem unreasonable not to oil a piece of mechanism when it fails
to work freely. It seems natural to suppose that oil will make any
mechanism work more smoothly and freely, but oil produces quite
the opposite effect when applied to a photographic shrrtter. Among
the most important parts of a shutter are the pumps, sometimesView original page 26Related documents and language editions
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