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Author Topic: Basic Flash from a tech standpoint  (Read 5803 times)

macgyver

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Basic Flash from a tech standpoint
« on: January 09, 2007, 02:16:01 am »

I've always been an available light shooter and have only recently started to get into serious flash work.  One of my biggest inspirations has been reading the Strobist blog (http://strobist.blogspot.com/), which I love.  However, it's made me realize how weak I am on some of my most basic knowledge how flash photography works.  Do any of you know of any great sites dealing with very, very basic flash know-how, especially from the technical side.  IE: the effect of shutter speed and aperature, ratios, sync cord usage, etc etc.  I would greatly appreciate any help available!

Thanks folks.

-mac
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Hank

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Basic Flash from a tech standpoint
« Reply #1 on: January 09, 2007, 11:12:53 am »

I'm not sure about online sources, my early learning predated the internet and was from books, workshops and demos.  The strobist is excellent, but if you want even more basics, you might check into some of the better photo texts.  I have such a stack of (now older) texts and reference books in our library that it would be hard to single out one as best, much less know whether or not it was still in print.

Of all the offline sources I have seen, the tutorial videos from Chimera were the most meaningful to me, especially those produced by the late Dean Collins.  I've linked their tutorial page, but did not open them to compare with the videos or to see if Dean in fact participated in those.

I'll give it some more thought and post a follow-up if I come up with other sources.  Looking back on a career of strobe use, it occurs to me that over and above learning the bare basics, real creative latitude comes from recognizing their relationship not only with each other (using multiples), but also with available light.  E.g., while most folks think of cameras and strobes in terms of max synch speed, their real utility comes in using them at SS much lower than max, thereby allowing ambient to perform a greater role in the final results.  While my camera might sync and 1/250, I regularly use the strobe on seated models at SS as slow as 8 seconds or so.
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stever

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Basic Flash from a tech standpoint
« Reply #2 on: January 09, 2007, 11:59:52 pm »

do you have a particular use for flash?  the techniques and in some cases equipment is different

i also found the Strobist interesting, but the emphasis on off-camera setups for mostly posed situations doesn't fit my use

i'd start by considering flash as fill vs main lighting

fill is fairly simple - set the flash to about -1 1/2 stops -- for people and wildlife (although with wildlife you'll need a fresnel lens flash extender which costs $50)

flash as primary light gets complicated and opens up all the multi-flash, off-camera ------

my main use of primary flash is for people indoors and macro (different setups)
  - for people, i use a Gary Fong Lightshpere with my Canon 550 - as long as there are white ceilings, this gives good overal illumation and pretty natural light on the subject without resorting to off camera/multiple flash
  - for macro i use the Canon twinlight with one long arm borrowed from my underwater setup to provide side/backlight - wildflower photos when it's breezy

there are a few flash threads and a reference to a site (that i can't find now) that explains Canon flash compatibility and something about how they work (which the manuals mostly do not)
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howiesmith

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Basic Flash from a tech standpoint
« Reply #3 on: January 10, 2007, 06:31:46 pm »

Flash is pretty straight forward.  The important thing to remember is the flash duration is very short.  

The flash exposure is set by the f/stop (and the flash power and flash-to-subject distance).

The ambient light is then set by shutter speed with the selected flash f/stop.  

Just be sure the shutter speed is at the camera's sync speed or slower.  This will set the proper exposure for both fill (underexposed flash) and flash as main light source (under exposed ambient), and everthing in between.

The problem is "seeing" the effect of the flash.  I suggest a flash meter (takes into account bounced flash inside), as the guide number method can get confusing with multiple flashes and bounced light (at least for me).

For flash only lighting, modeling lights are handy, especially if they are proportional to the flash output.  To make things easy for me, I use flash units with the same full power and proportional modeling lights.  Then, with minimal ambient light, what I see is what I will get.

For fill (flash and ambient), underexposing the flash a half stop to a stop and a half is about right, but you can easily control this for your situation and preference.
« Last Edit: January 10, 2007, 06:32:54 pm by howiesmith »
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Hank

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Basic Flash from a tech standpoint
« Reply #4 on: January 11, 2007, 09:38:41 am »

I did a quick scan of our library, and I've got to say I am surprised (and a little embarrassed) with how old our materials are.  The bad news is that there must be multiple newer sources available, either updates or newer volumes, but I simply am not acquainted with them.  The good news is that through used book stores, the volumes I cite should be cheap.

Here are three that provide useful aspects to answer your question, but no single one is as all-encompassing as I would like.


"The Photographer's Studio Manual" by Michael Freeman, 1984, Amphoto, ISBN 0-8174-5464-0 (pbk.), 256pp.

"Understanding Photography" by Carl Shipman, 1974, HP Books, ISBN 0-912656-24-7 (pbk.), 224pp.

"Beyond Basic Photography" by Henry Horenstein, 1977, Little Brown & Co., ISBN 0-316-37312-5 (pbk.), 242pp.

I have to guess that Zuganet has very useful basic info in their archive of articles, but haven't delved deeply enough to be sure.  Looks like there are useful articles at Professional Photography 101.  I'm not sure about access for non-members, but PPA degree programs, classes and workshops are among the principal education sources for studio photographers who make their living with strobes.  Surely among their articles and links you will find useful info.

Hope this additional info helps.
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howiesmith

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Basic Flash from a tech standpoint
« Reply #5 on: January 11, 2007, 10:29:56 am »

Quote
I did a quick scan of our library, and I've got to say I am surprised (and a little embarrassed) with how old our materials are.  The bad news is that there must be multiple newer sources available, either updates or newer volumes, but I simply am not acquainted with them.  The good news is that through used book stores, the volumes I cite should be cheap.

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The really good news is the theory hasn't and practice are the same.  Flash is still flash.  The equipment gets newer, and how to operate the controls changes.  Some things are now done by the equipment, but flash still does the same ole thing.
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macgyver

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Basic Flash from a tech standpoint
« Reply #6 on: January 11, 2007, 01:07:07 pm »

Thanks folks, I appreciate your replies.  The library is on my (ever growing) list of things to do.
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John Camp

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Basic Flash from a tech standpoint
« Reply #7 on: January 11, 2007, 01:20:39 pm »

There's a company called Lumiquest:

http://www.lumiquest.com/

That makes on-camera flash modification products -- various kinds of little shields and tiny umbrellas, etc., for on-camera flash, or simply a bunch of flash heads. The guy who runs the company, whose name is Quest C. Crouch, has written guides to small-strobe flash photography; the guides are very simple and very useful. Essentially, his argument is that you can do very sophisticated flash photography with only small battery-powered flash heads. I've only seen the guides in photo stores and they can be hard to come by. Currently, there's only one listed on Amazon:

http://www.amazon.com/FLASH-Available-Ligh...h/dp/0974826707

His site also has a lot of good information.

JC
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