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#1
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Flash - one more time
Been ill and forgetful. Forgive the stupid question.
Using flashbulbs. Say I know the outcome for one bulb, and need four more stops. How many flashes do I have to make? 15? Mr. Blank - you can give me grief on this one. I can hardly believe I've forgotten. jj |
#2
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Flash - one more time
"j" wrote
Using flashbulbs. Say I know the outcome for one bulb, and need four more stops. How many flashes do I have to make? 15? All total - 16. In addition to the flash on the camera which you aren't counting - 15. All 16 flashes have to be identical to each other. |
#3
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Flash - one more time
"j" wrote in message ... Been ill and forgetful. Forgive the stupid question. Using flashbulbs. Say I know the outcome for one bulb, and need four more stops. How many flashes do I have to make? 15? Mr. Blank - you can give me grief on this one. I can hardly believe I've forgotten. jj Each stop requires double the light. So, if at some stop you need 1 bulb then For 1 additional stop you need 2 bulbs, 2 more stops 4 bulbs, 3 more stops 8 bulbs, 4 more stops 16 bulbs. However, if they are fired successively you will encounter what is called the intermittantcy effect which reduces the effective exposure. Intermittantcy effect varies with the emulsion and also becomes worse as the number of exposures increases. In general, films with less reciprocity failure will have less intermittancy effect but you will have to experiment a bit to find the right correction factor. This is, of course, also true of strobe flash. If you are using Kodak film you may be able to get more data from Kodak customer service. In the USA the number is 1 800 242 2424, ask for extension 19 (professional products). Note that color films may show a color shift when exposed intermittantly. -- --- Richard Knoppow Los Angeles, CA, USA |
#4
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Flash - one more time
"Richard Knoppow" wrote
[...] However, if they are fired successively you will encounter what is called the intermittantcy effect which reduces the effective exposure. [...] Indeed. I became familiar with intermittency effects as a printer. Thanks for the reminder. I can set them all off at once. It's handy that they are all Edison base. |
#5
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Flash - one more time
Nicholas O. Lindan wrote:
"j" wrote Using flashbulbs. Say I know the outcome for one bulb, and need four more stops. How many flashes do I have to make? 15? All total - 16. In addition to the flash on the camera which you aren't counting - 15. All 16 flashes have to be identical to each other. And you may wish to add some more to allow for intermittency effects. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 07:30:01 up 13 days, 16:38, 3 users, load average: 4.15, 4.25, 4.30 |
#6
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Flash - one more time
"Jean-David Beyer" :
And you may wish to add some more to allow for intermittency effects. Jean-David - Thanks, but the bulbs are all Edison socket type. It's SOOOO easy to build monster and multiple simultaneous flashes with such inexpensive hardware. Maybe I'll have an invitation to some of you all to the Burn the Bulbs events. |
#7
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Flash - one more time
j wrote:
"Jean-David Beyer" : And you may wish to add some more to allow for intermittency effects. Jean-David - Thanks, but the bulbs are all Edison socket type. It's SOOOO easy to build monster and multiple simultaneous flashes with such inexpensive hardware. Maybe I'll have an invitation to some of you all to the Burn the Bulbs events. Can you match some of O. Winston Link's events? I doubt the public was invited, but he could photograph an entire railroad train at night with the things. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 10:15:01 up 14 days, 19:23, 3 users, load average: 4.77, 4.45, 4.32 |
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