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Explore the world of vintage lenses through repair notes, real test shots, and detailed archive threads packed with images.

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How to sum up flash guide numbers?
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Hello.

Say I have flash with GN of 17. If I add another flash with GN17 next to it, what will be the output power? according to wiki, to double GN, you need to quadruple the flash power. this means, with two flashes I'll be getting 17+17/2=25 ?


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Probably 1 stop extra. Try it in manual mode on digital