Photographic Studio Flash Explained: Photographic Studio Flash Basics
Photographic Studio Flash Basics. Good photographic studio flash kits differ from on-camera flashes in many ways. In addition to providing considerably more flashpower, studio units are designed to be used with a wide variety of light shaping accessories such as umbrellas, softboxes, grid spot attachments, barndoors, beauty dishes and others.
Each of these accessories provides a different quality of lighting, allowing the user to precisely compose light to suit his purpose. Studio flash units are often used in multiples, with as many as four or more lights often used to obtain intricate combinations of studio light and shadow.
The wide variety of setups involving studio lights demands that the user abandon Automatic Exposure Settings in the camera. Cameras must be set to Manual Mode with aperture and exposure time set manually. The power levels must be adjusted on each light separately in order to compose the scene, and a flashmeter is generally used to determine the appropriate camera lens aperture setting.
Modeling Lamps In order for the photographer to be able to visualize what the scene is going to look like when the picture is taken, studio flash units contain Modeling Lamps. These are incandescent lamps of modest power that are placed in the studio flash in such a position as to mimic the light that will be emitted by the flash when the actual picture is taken.
There are certain considerations that must be met if the photographer is to be able to rely on his modeling lamps to provide a What-You-See-Is-What-You-Get (“WYSIWYG”) preview of the actual shots. Some manufacturers ignore the requirements for truly accurate modeling lamps. This can result in exposures that don’t look like what the photographer expected and the requirement of many test shots and adjustments in order to achieve a certain lighting effect. Accurate WYSIWYG modeling dictates the following:
1. Modeling lamps must accurately track flashpower adjustments in order to provide a constant relationship of modeling Lumens to flash Lumenseconds, with errors no greater than 1/10 to
2/10f at any power setting. 2. Modeling lamps must project similar beam patterns to the flash.
3. Modeling lamps, like the flash, should be immune to variations in power line voltage in order to maintain consistent accuracy regardless of fluctuating power lines.
In this regard, all studio flash systems employ high-precision voltage regulation of both modeling lamps and flash to provide consistent output at all power line voltages from 105 to 135 Vac.
Power Range Studio Flash Photography requires a wide and controllable range of flashpower in order to meet all lighting and aperture requirements demanded by a given session. Typical flashpower requirements can range from 5 or 10 Wattseconds (Ws) per unit up to 600 Ws or so. Outside the studio, when shooting in larger spaces, power requirements can be as high as 2400 Ws or more.
Such power levels usually dictate the use of separate power packs and flash heads because of size and weight restrictions. It is paramount that the studio flash units have a suitable base power range for the type of work anticipated, and be capable of a wide range of power adjustment with excellent accuracy, consistency and modeling lamp tracking. We recommend 160 Ws to 320 Ws units for the small studios and 640 Ws units for larger studios. If you have too much power, you may not be able to dial the power down enough to get low aperture numbers with close light to subject distances.
