Flash Photography with the G Cameras

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The G cameras have two basic flash modes:

1. The camera CPU is aware of a flash unit and controls the duration of the flash. The flash unit must be a Contax TTL compatible flash unit in order for the camera to be aware of the flash and to control the flash duration. 
2. The camera CPU is unaware of the presence of the flash. The hot shoe and PC synchronization terminals are active. If a flash is present, it will fire when the shutter release is depressed. 

Connections. A Contax TTL compatible flash unit must be connected to or mounted on the camera’s hot shoe.  Flash units that are not TTL units or flash units that are Contax TTL compatible but are set to non-TTL settings may be mounted on the camera’s hot shoe, or connected to the camera through the camera’s PC synchronization terminal. 

Contax TTL compatible flash units. Contax as well as third party manufacturers such as Metz and Sun Pak offer Contax TTL compatible flash units. Simple flash units have Manual and TTL settings. More sophisticated flash units have Manual, Automatic and TTL settings as well as additional features such as second flash tube, tilt and swivel head, and adjustable aperture and/or adjustable power output. Metz offers a range of reliable and flexible flash Contax EEL compatible units in every price category, as does Sun Pak. 

Washed-out is too close. The G cameras do not warn when the camera to subject distance is so short there may be too much flash for correct exposure. When working at short distances, check the GN equation or the flash table for the ISO, aperture, and distance to make certain that the exposure will be correct.  

Non-TTL compatible flash units. There are many non-TTL compatible flash units available from third party manufacturers. Perhaps the least expensive are recent models of the Vivitar 283 equipped with the VP-1 Vari-Power module. Yashica also offers inexpensive and reliable flash units. 

Contax TLA 140 and TLA 200 flash units. While less powerful, the TLA 140 flash is much less prone to Red Eye than is the TLA 200. The suggested retail price for the TLA 200 is US$400. The flash commonly is seen with a street price of US$200 to US$300. The TLA 200 has only Manual and TTL modes. It does not tilt or swivel, there is no second flash tube.  The output is not adjustable in manual mode. Considering the increased incidence of Red Eye and its other limitations, the TLA 200 flash is significantly overpriced at its street price compared to the available alternatives. 

GN. The GN or Guide Number of a flash is a measure of the power of the flash. The greater the GN, the more powerful is the flash. The GN is equal to the camera to subject distance multiplied by the aperture number for a particular ISO film, usually ISO 100. The guide number can be given in meters or feet. The GN equation can be used to determine the correct distance for a selected aperture, or the correct aperture for a given distance.

Warning Older High Voltage Flash Units. There are older flash units, typically older than 15 years that if used on the G cameras may damage the G cameras’ electronics. These units register high DC voltages across their contact terminals; DC voltages of 150 V or more are not uncommon. If you are uncertain as to the age of the flash, check the voltages using a voltmeter. Such units when mounted on a camera’s hot shoe should not be used on any camera other than a completely manual camera. Such units can be used via the PC synchronization terminal, but the voltage should be less than 10V DC.  

Exposure Compensation. The G cameras’ Exposure Compensation dial can be used to increase or decrease the duration of TTL flash and/or the overall exposure of a film frame. The overall exposure is a combination of ambient light and flash light. If the flash unit is mounted on the camera and turned on, use of the exposure compensation increases or decreases the overall exposure given to the entire frame.  

When a non-TTL flash unit is used, the exposure dial must be used to compensate the overall exposure of the frame that will be supplied by the flash unit. The required compensation is described later. 

Maximum shutter speeds. The maximum shutter speed for flash and shutter synchronization for the G2 is 1/200 sec. The maximum shutter speed for the G1 is 1/100 sec. 

Minimum shutter speeds. The shutter and flash will be synchronized at any shutter speed from Bulb to the maximum shutter speed for flash use with either camera. 

Flash uses.  Contax TTL compatible flash units can be used with the G cameras for automatic flash, key flash, fill flash, and slow shutter speed flash. Non-TTL flash units may be used with either camera for key flash, fill flash, and slow shutter speed flash. 

Off-camera flash. Contax TTL compatible flash units can be used off camera if they are connected to the camera’s hot shoe by a flash extension cord. Non-TTL compatible flash units can be used if they are connected to the camera’s hot shoe or pc synchronization terminal by an extension cord. 

Off-camera flash allows for the reduction of the harsh shadows and Red Eye created when the flash is mounted directly on the camera. 

Automatic flash. Automatic flash is the mode used when a Contax TTL compatible flash is connected to the camera’s hot shoe and the flash is turned on. The camera’s CPU controls the contribution of the flash’s light to the overall exposure. The camera’s CPU restricts shutters speeds for automatic flash to 1/60 second to 1/200 second for the G2 and 1/60 second to 1/100 second for the G1. 

Key flash, TTL mode. There is disagreement among users as to whether the G cameras can be used for Key Flash at a set ambient level when in Auto mode. 

Fill flash, TTL mode. There is disagreement among users as to whether the G cameras can be used for fill Flash at a set ambient level when in Auto mode. 

Slow shutter speed flash. Slow shutter speed flash renders the foreground normally bright when the overall scene is dim; for example, photographing a person in dim evening light. With the flash connected to camera’s hot shoe but turned off, meter the scene and lock that exposure using the AEL lever. Turn the flash on and release the shutter.  (Slow shutter speed flash uses shutter speeds of more than 1/60 sec. The camera must be steadied using some form of support. )

Key flash and fill flash, non-TTL mode. The camera’s CPU does not automatically consider the contribution of the light from the flash to the overall exposure in non-TTL mode. The operator must make the compensation manually using the exposure compensation dial. 

With the flash connected to camera’s hot shoe or pc synchronization terminal, use the exposure compensation dial to reduce the overall exposure by the amount that will be contributed by the flash. For example, if the fill flash ratio is 1:2, reduce the overall exposure by one full stop by setting the exposure compensation dial to –1. 

Slow shutter speed flash, non-TTL mode. No compensation to the overall exposure is required. 

Flash calculations. Some typical calculations are included in the Accessories FAQ.