Which flash unit should I buy for my SLR camera?in Miscellaneous
By fmueller/Frank (1,202)
on September 4, 2002 2:24:52 AM CDT
IntroductionMany people have difficulties to choose the right flash unit for their SLR camera, and end up buying a flash of the same brand as their camera, just to be on the safe side. However, this is not always the best, and often not the cheapest option. Many of the older manual focus SLR cameras can't even make use of a 'dedicated flash'. Many very cheap flashes are available on the second hand market, eg on eBay - if only you knew what to look for. This article tries to explain which flash will fit your camera, and how some of the older flash units work.
Types of flash unitsIn principle there are three types of flash units, and they differ in the way a correct exposure is achieved:What is TTL Flash? For TTL (through the lens) flash metering, the flash uses the light meter of the camera. To make this possible, the camera and flash need to be able to talk to each other; ie. you need a dedicated flash. If your camera does support TTL flash metering, you could still use an auto or fully manual flash unit, but it would be better to get a flash that supports the TTL flash metering of your camera. TTL flash metering is particularly useful if you shoot with filters, teleconverters or extension tubes, because there is no need to manually compensate for them, as you would have to do with auto flash or manual flash. TTL flash metering can also be useful when shooting with lenses of extreme focal lengths (eg 20mm wide angle or 400mm tele), when the area that the auto flash sensor meters is not representative of the whole picture. A flash that is capable of TTL flash metering only, can only be used on a dedicated camera. What will I need to do to use a TTL flash?
What else is there to consider?Bounce flash You will want to use direct flash only when it is unavoidable. Bouncing your flash off a wall or ceiling usually gives much more pleasing effects, and the pros do it all the time. To be able to do this, you will need a flash with a head that can be tilted and swivelled. Some units only offer tilt, and you can get away with it, but you need swivel if you want to bounce the flash off a wall for landscape format shots, and to bounce off the ceiling for portrait format shots. Bouncing your flash is also useful if you want to use your flash with wide-angle lenses. Most flashes cover the angle of view of a 35mm wide-angle lens. You can increase the angle that is covered by the flash by using a wide-angle diffuser, a product like the Stofen Omnibounce, or by simply using bounce flash. Thyristor flashes Every time you fire a non-thyristor flash, all the power that would be required to fire the flash with full power is lost. If you fire a thyristor flash with less than full power, it will save the energy that was not required. This helps to improve flash recycle times, and helps to save batteries. Trigger voltage Some older flash units use very high trigger voltages. If they are triggered via the hot-shoe of modern electronic cameras, this can damage the electronics of the camera. There is quite a bit of information about this on the web; eg here and here. Non-standard flash shoes Some cameras, notably Minoltas autofocus cameras use non-standard hot shoes. This makes it necessary to use a dedicated flash, or to use a special adapter.
Some LinksAll about electronic Flash
Electronic Flash Information
Kodak Flash Photography
The Birth of Electronic Flash
Flash Trigger Voltage
Robert Monaghons Page
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