The Art of the Manual Flash

Started Jun 9, 2013 | Discussions thread
Zee Char
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Re: The Art of the Manual Flash
In reply to Tim Wheeler, Jun 16, 2013

Tim Wheeler wrote:

Manual flash is posible, using the flash's Guide Number. That's what photographers used to do before auto flash and TTL flash came along.

You will find the guide number in your flash's instruction manual, or online.

Set an aperture that equals the Guide Number divided by the distance.

eg, the SB900 GN is 131 (if measuring in feet) or 40 (if using meters). This is for ISO 100, full power, and 35mm zoom.

Therefore, at 6 feet, the exposure is f22. (131÷6 = 21.8). Or f11 at 1/4 power. Or f5.6 at 1/16 power.

I used to have a chart taped to the flash head, and became used to estimating distance and changing settings quickly.

With modern flash units, your preferred exposure may be different to the calculated one. Just create your own exposure chart.

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Tim Wheeler
www.wheelerstudios.com.au

I used to wonder how the film guys did this until I learned about the Guide Number system. Works well. If you shoot often enough it eventually becomes second nature. I'm still gonna stick with ETTL.

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