Connoisseur and the Contax User manual

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I.
THE IDEAL
MII\IATURE CAMERA




Due to the perfection  of the miniature  camera, amateur
photography  during  the past few years has developed
along altogether fresh lines. The extraordinarily   universal
performance of a high-clase modern miniature camera ischiefly due to the fact that even under  difficult  conditions     I{                                                                        .i
as regards light, movement of the object etc.owell exposed              i
and very sharply defined negativeso capable of consider-                                                                                                              'il
able enlargement, can be obtained                                                                                                                                                                                tl':l
                                                                                                                                                                                :r'liJ' . 1
fn  order to obtain these results, however, the use of a
eufficiently  fine-grained  film  is essential  for  the  repro-           a;fl
duction of very fine detail.  Several makes of cine-negative           .nlfilm  possess the  required  properties  to a high  degreeo                ,"rI':
and  for  thie reaeon the Contax has been designed for                   't
use with  a  high-clase  cine  negative  film   of  etandard                         i
width  (35 mm.)                                                                                                    I,if                                                                                                                                                      ,  l

Apart  from  the  film  questiono however,  the  design  of                                                                               -tthe camera  itself must  fulfil,  in  all respects, a number
of  conditions,   if  results  of  first-rate  quality  are to be
obtained. Above  all, the camera must be equipped with
lenses   of  such optical  correction  that  the  optical
definition  enables full  use to be made of the  fine grain
of the negative.

The necessary sharpness of  the  negatives  is  therefore
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a   -
ll:l
J       r      first  of  all obtained by the use of a suitable  film and of
L         high - quality   optical  equipment.   To  a  considerable
lI          extent,  however,  sharpness  is  also  dependent  upon
I        minutely  accurate focussing, which entailsafocussing
        mechanism of easy and rapid operation.   It  follows that
         the  film must  lie  absolutely    flat   in  the  film  gate,
ui       so as to ensure the eame accuracy ae with  a plate and
          plate holder.  All these highly important  points muet be
           carefully considered in the design of an efficient miniature
        camera.

         The accuracy "J the         mechanism                              Jocussing
              obtaining absolutelysharpI         Jo,                       Jocus

            is of much  greater importance  with  a miniature  camera
         than  is generally assumed.

                It  ie an entire mistake  to think  that  such a high degree
           of accuracy in focussing is not  called for with  a lens of
          short focuso as usually employed in a miniature  camera,
         since  the  hyperfocal  distance,  or  so - called  "depth
           of focus",  is always very considerable with  such lenses.
I         This idea is based upon the erroneous aesumption  that
I         the sharpness of focus obtained over the range of depth
           of foeus is equal and constant throughout.   In  realityo
        however, the so-called range of depth of focus lies between
        two  extreme  pointso marking  the  limits  of admissible
         unsharpness. Between the rear and front  of this region
          of depth of focus,there is a zoneof maximum  sharpness
         representing the best attainable  degree of sharpness in
         focussing, and  it ie this narrow zonewhich  is of such great
         importance   for   miniature   cameras.  Such  accurate
         focussing is, howevero only  attainable   if  all parts  of the                                                         'greatest        lene-focussing mechanism work  with  the
        accuracy.

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          But the performance of the shutter   of a reliable miniature
         camera must also be in keeping with  the technical con-
            ditions imposed by  the denland  for absolute sharpness
                                              camera                                                       mustI          thereforeof the negatives.be fitted Awithhigh-classa shutterminiaturesubjecting                                                           the  single
           points of the negative to such short exposure that,  evin
           with  r_apidly moving  objects, no undesirable blurring  is
         caused by the movement.  This condition, however, can
           only be fulfilled  by  r  focal-plane  shutter.    It  is further
          necessary to  limit  the slight distortion, which can never
         be quite avoided *ia_h a focal-plane camera, and regarding
          which more is said below, to such a degree thatffor    ail
           p_ractical purposes,  it  is altogether  eliminated.   Lastly
          the focal-plane shutter must be of material   to withstand
              all mechanical and  climatic  wear-and-tear  encountered
             in actual  practice.

                 ft  is, moreover, a well-Lnown fact that large and relatively
                cameras, as generally used in the past, could b-e              l"r..y
          held more easily and steadily for exposures made in the
         hand than  small and light  cameras. For obtaining  per-
            fectly  sharp miniature  pictures,  it  is essential to eniure
          perfectly  steady  holding  of the camera. For this
          reason, a reliable miniature  camera must be designed in
         such a manner that   it can be held securelv and steadilv
            in the hand,  in spite of  its small size and small weighi.
        The                    difficulty   in  holding  a  small  optical  instrument             _
          ab_solutely steady is apparent to everybne who has once
          h_elda pair  of binoculars  of large magnification and has
         observed how  the beat  of the  pulse and mere act  of
          breathing  cause the image to mbve up and down con-
            tinually.  For this reason special care h-as been bestowed
        upon  the  shape  and  weight  of  the  Contaxo so as
           to  eliminate  all sources of trouble  of  this  kind  to the
        maximum  degree.

           Lastly,  a modern  miniature  camera must be capable

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of being employed  for branches -of photography  other
than  thi  ueual imateur  practice, bY the use of access-
ories which can be fitted to the camera in a few seconds.
To give a few examples, an ideal camera of thie description
sho;ld  be able  to  serve the purposes of the  scientist
requiring  detailed large-scale photos, of the medical man
deiiring"clinical   phot--oe,of the Press phologr-apher for
unobtrirsive   snaps  either  indoore  in  artificial   li_ght or
for rapid  "xposot"s  as needed in sPo-rtsphotography,  for
technical phbtography  even of small mechanical  parts,
for  the  eiplorei   for iong-distance  photography  with- a
telephoto  i"os  where  focussigg  of -the  picture  on the
ground-glass screen may be desirable.

A  miniature   camera   fulfilling    all  these  and  similar
requirements  and   giving   negatives  -of  unsurpassed
qu-ality, whether taken by  " professional portrait  photo'
grapher, fastidioug amateur, scientific specialist, engineer,
or Pressman can be said to be a

     really  Uniaersal Camera

in the true sense of the word.

The  Zeies Ikon  A.-G.,  Dresden,  the  world-renowned
concern comprising several of the oldest and best known
German camera works,  set itself  the task  of designing
a univereal  miniature  camera  as describedabove.
As the outcome of years of cooperation between experien-
ced engineers, scientiste, opticians and mechanicians, all
the numerous  technical   difficulties   involved  were  sur'
mounted, and   it  became possible  to  place a camera
on the  market,  representing camera perfection      the
            66par &cellence".  The  camera  embodyinginstrument
 the fruition  of  all this  scientific research, modern rl&rrU-
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tI.
THE CONTAX
AS A UNIVERSAT CAMERA

In  all respects, the Contax  fulfils the highest expectatione
and  requirements  of  the  modern  photographer.  The
underlying  principle  of its design is that   it  is
    the Camera Jor Eaery Occasion

T h e  C o n t a x   c o m p l e t e l y  r e p l a c e s :
l.  The old solid  tourist  folding  camera  with  its
     long bellows extension and reliable focussing on the
    ground glass. These facilities are fully  available with
     the  Contax.

2.  The modem  emall roll-film   camera,  with  ite
     constant readiness for action and large-aperture lens.
     In   all  respects, the Contax, which likewise takes a
      roll-filmo  is immensely the superior, in  its technical
     perfection,  of the  ordinary  roll-film  camera.  With
     the  Contax,  for  example,  double  exposures  are
     automatically  prevented.

3.  The press and sports camera.  The focal-plane
     shutter of the Contax, permitting  exposures as short
    as 1/r*o sec., represents the most  highly  perfected
    design on the market. For  all practical purposes it  is
     indestructible.  Even  the most  rapid movement  is
    reproduced with great sharpness.Moreover the Contax
        ir superior td the Press and sports camera by virtue
     of the small  size and inconspicuous  design
    which make  it  possible to take  snapshots   un-
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 Fig. 2.  Contax  with  Zeiss Ikon  Eguipment   for Photo-nricrography

    observed.  The fact that a serics of 36 oxposrrr(.s
    can be -1{"   in rapjd succession is of spccial i: rr-
     portance.             The remarkable sharpness enablcs enlurgc-             _
    ments to be made on
     a very  considerable
     scale from the whole
     or  parts  of the neg-
     ative.

4.  T h e s p e c i a l  c a m -
    e r a of the scientist or
     engineer. The C on -
        t ax can be used both
     for  copying  objecrs
    same sizeoas also for
    photo - micrography.





          PROBOSCIS OF FLY
     Photo-micrograph by Siedentopf

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                            Photo  by  Riibelt,   afternoon  December  sun,  1/rooosec., with  //2  Sonnar  at f15.6

           The Contax, in conjunction  with  its multifarious  access-
               ories, which extend almost indefinitely  the uses to which
             the camera can be Puto represents an  entire  system
            o f m o d e r n p h o t o g r a P h Y .
             The Contax is the modern uniaersal  roll'
                   miniature caTnera"J unsurpassed ffic-                      fil*
               iency and all-round aersatility.
              This bold claim  calls for  proof.
           The followiog pages are therefore devoted to describiog
               the entire design "t  the Contax in  its main
                 details,
             so that  the  experienced photographer  will  be able  to
             form  his own opinion regardiog the chief characteristics
            and features  of this  precision miniature  camera.

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 III.
CONSTRT]CTIOI\OF THE
CONTAXAI\D ITS CHIEF'PARTS

 l . S h a p e  a n d b o d y o f   t h e  e a m e r a
As           mentioned  in the  introduction,  the  liability    -llready
to blurring  due to movement  of the camera during  th-e
exposure  is  specially  great  with  miniature  cameras.
A_part frola  unconscious movement  on the  part  of the
photographero  which  the  camera  designer cannot  of
                                course provide against,
                                  steadiness when hold-
                                    iog the camera is intim-
                                     ately  connected with
                                                its    general   shape,
                                 weight and dimensions.
                                Exact research regard-
                                    iog  the best form per-
                                       mitting  safe and steady
                                   holding  of  the camera
                                          in  the  hands  of  the
                                photographer was car-
                                      ried out, and  as a r€-
                                         sult of a series of ex-
                                  periments, it was found
                                      that  the  best  results
                                  could be obtained  by
                              making  the  b o dy   of
                                   the   camera   nearly
                                                   r e c t a n g u l a r .   T h i s
                                       fact was of course made
                               use of when designiog
Fig. 3.  How  to hold  the Camera       the Contax.

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Moreover the form  of the Contax  is a help in avoiding
a  tilted  position when  holding  the camera'  since the
rectangulir   outline serves as a guide in keeqing  it exa_ctly
level. Incidentally,  the form corresPonds with the modern
general  artistic  preferettce  for  smooth  surfaces cutting
each other  at  right  angles.

The Contax  is made with  an all'metal  body  consisting
of a light-metal  casting.  As every expert  will_ confirmo
cast camera bodies possess great  rigidity  and are not
subject to deformation  of any descriptiono thue rendering
them  superior to  all other typeso as for instance drarnnr
or stamped metal bodies.



2 . A c c e s s i b i l i t y

Every  camera should be designed -so as -to  allow  of
thorough  cleaning  of  the  interior  from  time  to time.
This  iJ specially necessary in the case of cameras- u_sing
roll-  or cine-fiIm.  Apart  from the accumulation  of dust,
small  particles  of  film  or  perforation  chips  tend   to'
collect in the camera, where they can give rise to serious
trouble. Above  all, the bearing  surface  around the
picture  aperture, as also the  sliding   track   of  the
iil-,    should be frequently  cleaned, and any  particles
of emulsion removed.

This easy accessibility, which__is regard.ed ae a matter
 of  coursi  in  the  design of  all  cine eameras and  cine-
projectors,  is also a feature  of the Contax design. -T-h"
br"t   of the camera can be removed,  thus enabling
the  interior  to be cleaned.  Incidentally  the removable
back  greatly  facilitates  the insertion  of the  film  in the
camera.
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            Fig.  4.  Contax  opened

      The  detachable   back   is made of  metal  of  great
        hardness.  rt  is absolutely  light-tight  and is  fitted  with
       a  spring  pressure plate  to ensure the  film  being kept
         perfectly   flat  in  the  picture  aperture.





           Fig.  5.  Back  cover of Contax, showing pressure plate

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   3 . P i c t u r e A p e r t u r e  a n d F i l m G u i d e

   As mentioned aboveo the efficiency  of a miniature  camera
   depends to a large extent upon the  filnl  lyl"S  absolutely
     flai  in the  pictuie  aperture'  so that  the  flatness  of the
    sensitive  su-"fac" is nbt  inferior  to  that  of the  perfectly
    rigid dry plate. This is the case with the Contax. Above
     .ia   l"t-ow  the picture  apertureo and parall_el to  its long
    sides, are two emboesedf narrow metal guid'es. The two
    inner  guides are arranged b_elow the two  outer onee to
    the exient  of the averige-guidesfilm  thickness,  1trs film  bgtg
   drawn  along the  outer         from-  left  to  right.  .Th"
    spring-piessingp"es*t"   plate bears against the two outer guid-eso
     tlor               t[e   film  gently-the    against  the  inner  gui.deg
     situatld   sHgltly  below      outer  ones.  For  pra_ctical
    purposes, iican  therefore be said that  the film  is drawn
                                                   only  against    ihrough  an extremely   flat                               9h3nne]' !e.a1ing    two narrow  guides, ihe height  of which corresPonds-to
    the averag" fi=l- thickness.  In this manner, the emulsion
    side  of  t-h"  film   is  afforded  ample  protectiono  while
    absolute flatness a4fl perfect alignment  of the film  in the
    picture aperture are ensured (see diagram).




                      Spring pressure plate

Outer guide                                         Outer guide




                                    Pictute  aperture

      Fig.6.    Sectional diagram  of the  film  channel
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         The eurfacee of the film guides of the Contax are ground
            with  the  greatest  accuracy  to  a  minute  fraciion  of
          a  millimetre,   60 t_hat they  are  absolutely  plane  and
            exactly at right angles to the optical axis.  In thls manner,
           the distance between the film and the various leneeg used
            with  the Contax  is always determined with the greatest
           accuracy.

       4 . N " g a t i v e  F i l m , D a y l i g h t - I o a d i n g
         S p o o I s , F i l m C a s s e t t e s
         The  Contax  ie designed_ to  take  etandard  perforated
             cine-film  of 35 mm. width   in  lengths  of aboui  Sr/n feet
            (I.60-nletres).. Each_ film  spool gives 86 pictures   of
         24x36 mm. size (about t6/ro-1Y; ins.). An- automatic
            film  counter  shows the number of exposures made.
            fn the Contax the long cherishedideal  of the roll-film
          camera,  embodl"g    all                                           and advantages                                   _the _features             of                           without   the  disadvantages,  has  bJen               _simpligity_
            realised.  such mistakes as doubl"  "*poJore have been
                                        completely   eliminated   by
                               means of the automatic  film
                                        feed.
                                     For ordinarywork,  the Con-
                                                                       t a x  D a y l i g h t - l o a d i n g
                                  Spool ehould be employed.
                                 The commencement and end
                                             of  the  film  in  these spools
                                       arq  provided  with  a  long
                                                  strip    of   perforated   red
                                      paper. Spools can be placed
                                                in  the camera and remov-tl                             ed  in  daylight  as with  the
t t         Fig.7.  Contax Spool          theordinaryfilm  beingroll - filmwoundcamera,from
                                    15

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the  full  spool on to the empty  one and being securely
protected against  light  by  the end paper  trailer.  Re'
winding  of the  film  is therefore  not  necessary. These
ooConta"x          Spools", which have given excellent results  in
actual  practice,  are  supplied  by  various  leading  film
makers.  At  the present time  the following  brandg are
on the market: Contax spools with Kodak Super-sensitive
(SS) Film  (260 Sch.), Mimosa Extrema  Film  (230 Sch.)'
                            Perutz - Persenso Fine - grain
                             Film  (2go Sch.) and  Zeiss
                             Ikon  Contax  Pernox  Film
                           (240 Sch.).  Agfa  Cartridges,
                          as well  as the  other  well-
                        known daylight packages, can
                             also be employed.
                       Where the photographer de-
                                sires to use longer or shorter
                              lengths   of  filmo  cut  from
Fig.  I a                        large  rolls, small cylindrical
Loaded  Contax                c a s s ett e s may be employed;
cassette, open                    In   this  case the   film   is
                               cut from  the long  roll  in the
                           dark-room  and loaded  into
                             the cassette.
                   Fig. I b      The film cassettes of the Con-
                Cassettecore   tax are so designed that their
                                      slits  are opened to the  full
                              automatically,   allowing  the
film  to pass freely as Eoon as the catch  of the camera
back is closed after loading the Contax.  In this manner'
the  film  does not come into  contact  with  the cassette
slits when  the  film  is moved on and  all scratches are
avoided.  This design also has the advantage  of closing
the  cassette  slit and rendering  the  cassette absolutely
light-tight  as soon as the catch  of the Contax back  is
released for opening the camera. The film can therefore
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           never be damaged in the Contax and is moreover always
           protected  against  light  penetrating  into  the  cassette,
           these features being the subject of a German patent.

         Where a dark-room  is always available, as it  is in studio
           establishments and  scientifil  laboratorieso cassettes may





              Fig. 9.     Contrary   to  the  descriptive   text,  the  illustration   shows
                            the  camera  with  the back removed  and the  cassette  slit
                          open,  in  order  to show  the  passage  of the  film  through
                            the  cassette  slits.  In  actual  practice  the  slit  will  always
                       be closed when  the back  is removed.


          be entirely dispensed with,  the film being simply wound
          from one spool core to another.

             In circumgtances where a second.cassette is not availableo
                     it  is possible to  insert an ordinary  metal  spool in  the
         camera in the dark-room  and to allow the  film  to run
          from  this spool into a film  cassette as described above.
           This process can also be reversed where required.   Inil           the  latter  case, however, the  film mugt be wound  into
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Fig. 10.        This shows film being wound from the Contax spool
                  into  the  {ilm  cassette





Fig.  lI.         This  illustration  shows the  film  being wound  from
              one Contax  spool  to  another


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          the caesette after exposure, for which purpose the Contax
             is provided with a re-winding mechanism. The re-wind-
           ing-  is necessary-when the well-known  daylight-loading
         packets  of  cine film  or  the  Agfa  cartridgeJ  are used.
           Attentio!_is  again drawn to the fact that the employment-and
           of these film cassettes is by no means necessary    need
          only be resorted to where special conditions make  their
         use advisable.  The  practical  Contax  daylight  spools
         which  require no cassette, represent

            the  rnost conaenient, simple  and,  reliable

         form of film material  for use with the Contax. By means
          o{ thg  daylight-loading  spool, loading and removal  of
          the  film  can be  effected  in  exactly-the  same simple
        manner as with  the  ordiriary  roll-film  camera.


       5 .  I n t e r c h a n g e a b i l i t y   o f  L e n s e s
        As the  size of the Contax  negatives  is small, namely
 l      madetulruxL"l,withins.lenses(24x36of mm.)oshort  focalnormallengthoexposurespossessingwill  b;a
           sufficiently  wide  angle of view.  Lensls  of  short  focal
 )        length will show the subject on a correspondingly reduced
 ?         scale.
+            It                   often                               however,  that  large  distant          -may                         lappen,
         objects  are to be taken with  the Contax ind  with  as
       much  detail  as possible.  There are limits  to  the  sub-
         sequent enlargement  of the negative, inasmuch as the
          details  of the enlargement tend to lose their sharpness,                     '        even where a very fine-grained film emulsion is employed.
         For  this  reason phot_ographs of  very  distant  bryLcts
         ehould be taken on as large a scale as possible in the firet
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instance. This can be done by the use of lenses of relative-                                ootly great focal length, i. e. so-cailed   el ep h ot o len s e s??.
Apart from the necessity of being able to vary the scale
of reproduction,  a realiy  univerial  camera must make





 Fig. 12.  Contax  with  long-focus  lens


 the photographer  absolutgly _io-d"pendent :t   tl"- ^lighting
 cond:itioni   ihethet    in  d"ylight-  or  artificial   light.  A
 mod.ern  photographer   wili   f"equeolly-- wish  to  take
 snapshots^at  so;iit  functions,  in the  ball-roonr  theatre,
 mu;ic-hall, snapshots in streets'-tt night and on numerous
 similar occasions. For this purpose
    lenses,t extrerneraPiditY

 wiil be required.
 Such lenses must naturally be of the most perfect optical
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                                   Fig. 13.  Contax  with  ultra-rapid   lens




correctiono so as to give clear and sharp definition, even
in the extreme corners of the picture.

Even the best lenses, however? would be useless,if means
were not  provided, permitting  the rapid and easy chang-
ing of the various objectives, which must be designed in
such a manner  that  they can be fitted  to  or removed
from the camera by a single turn  of the hand.  Moreover,
an essential condition  is absolute constancy and accuracy
of the distance between lens and  film.  For  this reason
the lenses must be equipped  with  mounts? permitting
convenient  and  rapid  interchan geability  and
giving absolute accuracy   of  focus.  The  special
b uy on et m o unt s with  which  all Contax lenses are
fitted  enable  all these conditions  to be  fulfilled.  The
design of the bayonet mount is based upon that employed
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                Fig. 14.  Contax  showing  interchangeability    of lenses



successfully for  years  in  cine cameras as used in  the
film industry. As the outcome of the practical e_xperience
gained in this industry,  bayonet mounts  affordiog  both
iapid  change  and  extreme  accuracy  as legards  the
diitance  between lens and focal plane, can be fitted  to
the Contax.  Every  Contax  lens  is securely and rigidly
fixed  to  the  camera and  yet  can be changed in the
space of  a few  seconds; at  the same time  absolute
accuracy of focus is ensured.


6 . T h e    l e n s e s o f   t h e C o n t a x
The standard  optical  equipment  of the Contax  is the
excellent
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        The Sonnar lenses will probably be new to most photo-
         graphers.  A  detailed  description  is  in  course of  pre-
          Paration.
        The Sonnar lens is characterised by three separate air-
        spaced elementso the  first and last of which act as con-





             Fig. 17. Section through  the fl2  Sonnar




         verging lenses whilst  the central element is in form  of
        a meniscus, curved towards the object. This fundamental
         construction  of the Sonnar which embodies six glass-air
         surfaces is maintained in all cases?wheth er 4? 6 or 7 single
a        lenses are employ.edr_aecordiog to  the desired rapidi-ty
          or foeal length.  A  characteristic  feature  of the Sbnnar
           is the  short  c amera  exten si on  required, i. e. the
         small distance between front  lens and focal plane of the
            film. fn the case of the univer salfl2 Sonnar, for example?
         the distance between the film and the front  lens is only
        about 1.15 times the focal length when the camera is set to
            infinity.   This  fact  is of great advantage, inasmuch as
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