PF300 Slow Peak Graph / Guide Numbers |
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| Guide Numbers | ||||||
| Tungsten film speed (reference). | 10-16 | 20-32 | 40-64 | 80-125 | 160-200 | 320-500 |
| Up to 1/25th & 1/30th | 200 | 280 | 400 | 550 | 800 | 1150 |
| To find f-stop, divide guide number by distance infeet between flashbulb and subject. |
| To find f-stop, divide guide number by distance infeet between flashbulb and subject. |
(Example: with film speed 40, guide number is 220 at a shutter speed of 1/125 sec., distance 10ft lens setting: 220 / 10 is f/22) |
| The above table is computed for 7-inch reflector. If a large studio tyoe reflector is used, stop down 1/2 to 1 f-stops. |
Read safety warnings printed on packaging. Avoid static. |
Numerical data is typical. |
| Return to PF300 flashbulb specification page |
| © Meggaflash Technologies Ltd. |