CONTAX AX Focusing, a relatively easy thing to do, has become the hot word in photography over the last ten years or so. It doesn't look like auto focus is going to wither away. Thirty five mm photography is more than dominated by auto focus cameras. HISTORY OF AUTO FOCUS SLRs In 1982 at Photokina CONTAX showed a 137 model camera with a motor mounted in the camera body that drove a shaft extending through the lens mount flange and into the lens. The lens had a light-weight helicoid that could be driven by the motor shaft. As the shaft turned the lens focused. Simple, elegant and the first of the marketable 35mm AF cameras. Needless to say, CONTAX never went into production with this new product. Minolta "up-staged" us. This inaction left everyone, outside of CARL ZEISS, scratching their heads. Why, when CONTAX had an early workable system, didn't they pursue and capture the AF market? CARL ZEISS LENS DESIGN The answer lies with the concept of lens design by CARL ZEISS. Previously, I mentioned the light-weight focusing helicoid in the prototype CARL ZEISS lens. This helicoid was made of plastic, with no back-lash in the focusing ring. Additionally, the lens elements were positioned and held in place by plastic spacer rings. Both of these components, while serviceable over the short term, were not up to the longevity and optical specifications of CARL ZEISS. Plastic has a lower coefficient of expansion than metal, leading to a conclusion that it may be a better basis for lens construction. The problem is that while metal will return to its original starting point before a temperature change, plastic may not. This phenomena is known as warpage. Plastic also has the added benefit of lower cost, but the trade off for this cost saving is shorter life due to higher wear. A focusing helicoid is a thing of beauty, it must be able to travel throughout its length without binding or snaring on the opposite member. No materials will slide against each other as easily and as well as aluminum against brass. One half of the focusing screw is made from brass, the other mating half of the screw is made from aluminum. For plastic to achieve this unimpeded flow over the focusing track it must be a very loose fit. The silky smooth focusing movement of a CARL ZEISS lens will last for at least 30 years with no visible change in the resistance to movement (back-lash) in the focusing system. Lenses, such as AF lenses found currently in competitive systems, have virtually no back-lash for two reasons. First any resistance to the focusing system must be overcome by the focusing motor, the more resistance, the bigger the motor required. Second, the plastic helicoid must be loose to avoid binding of the focusing mechanism. A manually focused lens with no focusing back-lash will not remain in focus easily. The looseness of the optical components does not allow for precise setting and holding of the focused position. Another feature of competitive AF designed lenses is the very small manual focusing ring incorporated almost as an after-thought. This small ring is not an after-thought though, it is a consequence of that small motor used to drive the lens to focus. The smaller the driven mass, the faster it will move. Another manufacturing benefit of the plastic helicoid and small manual focus ring is cost savings in materials and machining. The unit cost of production of AF lenses has plummeted to very low levels. Along with these cost savings measures, optical quality has suffered. You cannot find a photographer today who does not believe that the older manual focus lenses were optically superior to today's plastic marvels. CARL ZEISS would not sanction changing their lenses in any way to accommodate auto focus. These lenses have been honed over the years to a production level unmatched by any other manufacturer in the world. If we cannot move the lens to gain focus automatically, we can move the film. A NEW APPROACH Thirty-five mm photography has grown up around the idea that focusing is accomplished by rotating a focusing ring on a lens. We know this is the expected norm from our experience with the G1 where the customer is confused by being unable to figure out how to focus the camera manually. There are no exceptions to this focusing method in 35mm photography. There are, however, examples of other kinds of focusing methods in the field of photography. At the beginning of photography, and carrying on today as the monorail or view camera we find it normal to focus by moving the film plane. There are no compromises in focus quality by achieving focus in this way. CONTAX has designed a new type of 35mm auto focus camera. The main benefit of a system of this type is that lens quality is unchanged. There is no loss of optical quality what-so-ever due to the auto focusing procedure. The secondary benefit is that we offer automatic focus in the CONTAX system without compromising the supreme quality of the existing CARL ZEISS T* lenses. There are no adapters or accessories to purchase. The CONTAX AX uses all existing lenses in the YASHICA / CONTAX bayonet mount without compromise. AUTOMATIC BACK FOCUSING Our new CONTAX focusing system is called Automatic Back Focusing. The AX is composed of an internal camera body inside an exterior camera body. Two new technologies have been brought together to achieve this goal. The first is ceramic technology where a very finely finished ceramic rod acts as a guide rail and motor part to move the film plane forward and back to gain focus. Riding on this ceramic rod is a matching ceramic ring attached to the internal camera body composed of film gate, frame and pentaprism. Two microns (2/1000 mm) is all that separates one sliding component from the other. This gap is so small that special lubricants must be employed since normal grease or oils are particulate at 10 to 50 microns (10/1000 to 50/1000 mm). This super lubricant has a particulate size of less than 2 microns. The level of precision exhibited here is required for accuracy at the level of the CARL ZEISS lens and also to prevent chattering and misalignment of the film plane components. Another rod composed of metal with a lower fit tolerance is used to assist the ceramic rail and prevent chattering and misalignment. The combination of the two rails provides a railroad track-like surface for the film plane to ride on. Surrounding these rails is the block called the internal camera body, composed of the guide rail sockets (one is ceramic), housing, film gate, and pentaprism assembly. The second new technology is the Ultra Sonic Motor (USM). This is the mechanism that drives the ceramic collar and inner camera body forward and back on the rails. The virtues of the USM technology are precision control and extremely quiet operation. The Automatic Back Focusing system on the AX can move from minimum focusing distance to infinity or back in less than 450 ms. This is a very quick indeed. The time required to achieve an intermediate focusing distance is minute. Additionally, since the film is moving and not the rotation of the lens, we can focus long or short focal length lenses over the same time period. The AX offers auto focusing precision beyond any other camera in the 35mm arena, without compromising the manual focusing system one iota. CONTAX has applied for more than 100 patents now pending on the AX. When CONTAX innovates look out! AUTO FOCUSING SENSORS The AF sensors in the AX are deep in the bottom of the camera body. These sensors in conjunction with the USM and ceramic technology produce the finest implementation of auto focus in the world. The AX uses phase difference detection as the auto focusing method. More commonly we call this passive AF. CONTINUOUS, SINGLE or MACRO FOCUSING MODES Single AF is a system where the camera will lock focus on an object before it allows the user to shoot. The AX will not let the user take an out of focus photograph in the Single AF mode. Essentially, the camera has control and makes the focusing decision. Continuous AF is a predictive system that can anticipate the action of a moving subject. Further, predictive AF gives control of when to shoot to the photographer. It will allow the photographer to shoot whenever he feels the time is right. A Macro focusing position is also implemented on the AX. This mode positions the film plane to the maximum magnification, 10 mm behind the normal infinity focusing point. This film position will effectively add a 10mm extension tube into the optical system automatically when the lens is focused to its nearest focusing distance. The lens is focused manually in the Macro focusing mode. When in Manual focusing mode, the AX performs like all other CONTAX cameras, with the addition that the AF Button may be pressed to allow one time focusing assistance. The AF system will engage to help set the focus. When the AF Button is disengaged the camera immediately returns to a manual CONTAX. THREE CENTRAL PROCESSING UNITS (CPU) The CONTAX AX utilizes three CPUs to control all of the camera's functions. This is a more sophisticated computer system than any other camera system in the world. One of the CPUs controls the Automatic Back Focusing system, one is used to oversee auto exposure, and a third, the Indicator CPU controls wind / rewind, shutter charging and viewfinder indications. The amount of ROM memory available in the AX is 56k, the amount of ROM necessary to go to the moon with Apollo 7 was 64k. We are becoming very sophisticated, indeed. MOTOR DRIVE The AX allows selection of film advance speed at Single (S), Continuous Low (CL) 3 FPS, and Continuous High (CH) 5 FPS. A Custom Function (CF) will allow the rewind to occur automatically or upon the user's wish. Coreless motors are used to advance and rewind the film. This type of motor provides quiet, fast operation. SHUTTER SPEEDS The electronic shutter on the AX has a top speed of 1/6000 second in Aperture Priority and Programmed Automatic Exposure modes. The top shutter speed in Time Value (Shutter Priority) and Manual is 1/4000 second. X sync is 1/200 second or longer and the longest shutter speed in Programmed AE or Aperture Priority is 32 seconds (4 seconds in Manual or Shutter Priority AE). The shutter is a multiple bladed, vertical travel, metal focal plane shutter. As in the RTS III a selection can be made between a two second or ten second self timer. LIGHT METERING SYSTEMS The CONTAX AX offers the choice of TTL center-weighted average or TTL spot metering in a 5mm central area of the viewfinder. Light detecting devices are Silicon Photo Diodes (SPDs). These sensors are the most accurate metering cells with no memory that are available. The metering range for center-weighted average metering is from EV 0 to EV 21, while the sensitivity for spot metering is from EV 3 to EV 21. DX Control is available for automatically setting the film speed from ISO 25 to 5000, or film speeds may be set manually for speeds from ISO 6 to 6400. The user may check the exposure by simply depressing the exposure release half-way. Exposure compensation is also available in 1/3 EV steps up to +/- two stops. Automatic Bracketing Control (ABC) is standard in increments of +/-0.5 and +/-1 stop as in our other recent cameras. Due to the spot meter as well as the AF system in the AX a circular polarizer is required. VIEWFINDER The viewfinder of the CONTAX AX is very bright and contrasty allowing fast manual focus. 95% of the film area is shown in the viewfinder with a magnification of 70% of the real field size. The eye relief or Long Eyepoint is 25mm or approximately one inch. A horizontal split image screen with microprism donut (FW type) is standard. A diopter adjuster is built-in and adjustable from +0.5d to -2d. Also, a viewfinder blind is installed for times when the eye is not at the viewfinder during metering or shooting in automatic exposure modes. Viewfinder information is complete, aperture, shutter speed, exposure warning arrows, flash ready / flash OK indicator, exposure compensation, exposure counter, AF indicator and film plane locator are all visible under any viewing conditions with the LCD panel. FLASH CAPABILITY The TTL flash metering system on the CONTAX AX is of the type employed on the RX. That is, with the TLA360 enhanced flash capabilities are possible. The TLA360 can read the f stop selected on the lens and additionally the flash may be powered down to a less than 1:1 ratio in TTL by dialing in the output on the flash unit. CHASSIS CONSTRUCTION The chassis of the AX is made from high pressure / high temperature, steam annealed aluminum. The top cover of the AX is made from titanium while the front and bottom are manufactured from specially hardened aluminum. The weight of the AX body is 1080 grams (38.09 oz.) while the RTS III is 1150 grams (40.56 oz.). CUSTOM FUNCTIONS There are eight custom functions available in the CONTAX AX. CUSTOM FUNCTION 0 1 1. Exposure Check Button Exposure Chk AE Lock 2. Multiple Exposure Mode Nbr. Of Frames RTS III Type 3. Auto Bracketing Control 0 / + / - + / 0 / - 4. Depth of Field Preview Lock No Yes 5. Film Leader on Rewind In Out 6. Auto Rewind Now No Yes, Auto Start 7. AF Assist Emitter On Off 8. Beep in Single AF On Off Clear (CLR) BATTERY The AX uses 1 each 2CR5 lithium battery to power all camera functions. Battery checking is automatic. OPTIONAL ACCESSORIES All CARL ZEISS T* lenses are usable on the AX with no adaptation. A Flex Case C-5 is available along with the P-8 Power Supply which is used for an external power source for cold weather or other remote power source requirements. This is the same power supply that is currently used for the CONTAX RX. OPTIONAL D-8 DATA BACK A new generation data back is available for the AX. This Data Back prints between the frames, as do other recent data backs from CONTAX, or the D-8 will reserve the first two frames of film, advancing past them to start photography on frame three. Then upon rewind, the AX will download all of the exposure information used to create the images on the roll onto frames one and two. The D-8 can imprint the information next to each frame, on frames one and two, or the unit may be turned off. See the sheet attached for details on what information may be printed. Specifications will be uploaded at a later time. ??