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

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.

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

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.

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.
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/( )\ Shrewsbury, New Jersey http://counter.li.org
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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.

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