Alternative Lighting 101 (HOT MODEL)

Car headlights?

Will Thompson said:

Can you guess the lighting of this shot!

Doug & Asher I know you know but please do not tell!

Title: Almost Off Balance!
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I love the picture! What a lovely pose and a "Chinese" character to offset her and provide intriguing balance! Love it!

I'd vignette the edges and corners and print it!

Asher

Given the angle the light is coming from, the location, and the time of day, my guess is streetlight.

Bob Rogers said:

Given the angle the light is coming from, the location, and the time of day, my guess is streetlight.

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Oh, right. The angle means it is not car headlights. But streetlights would be more even, wouldn't they? Then, we have another take at the same location here:
http://www.openphotographyforums.com/forums/showthread.php?t=14449

Not Your normal Norman 200's with the Chimera Softboxes?
Too big a light source to be your Macro Ring Light.

Very nice, Will

Hi Will,

Here's my take: one flash in front of her extended leg, 45 degrees high, at low power. A second flash to camera right, higher, about the same power. Perhaps at least one of these is not a flash but some sort of streetlight or sign...

Now I can't wait to see how wrong I was LOL!

Nice shot by the way, I think moving her more to the right side of the frame would do good.

Regards

Ruben

Thank all of you that have replied!

Sorry not headlights.

Not street lights either.

There have been several close but incomplete guesses.


A hint all lighting was setup on location by me.

Will Thompson said:

A hint all lighting was setup on location by me.

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Double exposure!

Jerome & Ruben, You got it the closest first!

Ruben, Not quite 45 degrees but a crisscross pattern.

Kathy Close but your memory is off a tad. (Norman 400B x 2) (I might have given it to you but as a friend you know too much about how I shoot before I shoot it!

Bob, a good guess but not. A clue is in the lack of deep subject & curb shadows! (see photo with the Macro Ring Light off, shadow under the curb)

Asher, It is a surveyors mark you noticed on the curb!

Can you tell us what was the power setting on the strobes and iso you used on the camera?

So ISO200 and 2x50 W/S. Thank you.

It would thus seem that Canon 580ex flashes could have been used in the soft boxes (they give something like 100-150Ws at full setting). It is interesting to know that they can be a real alternative to lugging studio strobes and their large batteries.

Hi, Jerome,

Jerome Marot said:

So ISO200 and 2x50 W/S. Thank you.

It would thus seem that Canon 580ex flashes could have been used in the soft boxes (they give something like 100-150Ws at full setting). It is interesting to know that they can be a real alternative to lugging studio strobes and their large batteries.

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As I'm sure you know, a watt-second rating does not tell us definitively the total luminous output of the flash unit (in lumen-seconds) - since the relationship depends on what we might call the electro-luminous conversion efficiency of the flash system - and certainly not the luminous intensity-time product on the subject (in candela-seconds) - which further depends on what we can simplistically call the beamwidth produced by the reflector and so forth.

The guide number, on the other hand, nominally reflects the final luminous intensity-time product on the subject (there being a few little wrinkles in the usual formal definition).

Still, there are various rules of thumb that will let us make a scientific wild-assed guess (SWAG) of the relationship between the watt-second rating of a flash unit and its luminous intensity-time product as presented in terms of guide number.

If we use my favorite rules of thumb, we can say that a Speedlite 580EX flash unit, at full output and with its narrowest beamwidth setting (giving a guide number rating of 58 meters), might be comparable in luminous intensity-time product to a flash unit (with some "normal" reflector in place) with a watt-second rating of somewhere in the neighborhood of 75 W-s.

I say this not to dispute the values you stated but rather to support them. The relationship is so vague, and so dependent on factors not noted, that there is no significant difference between saying "100-150 W-s" and "about 75 W-s".

Best regards,

Doug

Indeed there is no rating in Joules for on body flashes, the ratings I gave were based on my rule of thumb estimates... which may have been a bit optimistic. 75 to 100 J is more like it indeed.

Jerome Marot said:

So ISO200 and 2x50 W/S. Thank you.

It would thus seem that Canon 580ex flashes could have been used in the soft boxes (they give something like 100-150Ws at full setting). It is interesting to know that they can be a real alternative to lugging studio strobes and their large batteries.

Click to expand...

More like 25 Watt Seconds since the 580EX capacitor limits the max Watt Seconds.

Will Thompson said:

More like 25 Watt Seconds since the 580EX capacitor limits the max Watt Seconds.

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That is quite pessimistic. The capacitor in these units is typically between 1 and 2 mF with an operating voltage between 300 and 400V.

Jerome Marot said:

That is quite pessimistic. The capacitor in these units is typically between 1 and 2 mF with an operating voltage between 300 and 400V.

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And of course a capacitance of 2 mF (not 2 µF, which we used to write "2 mF" years ago) charged to 400 V has an energy of 160 J (160 W•s).

Best regards,

Doug

I try to find more information on the light output of studio and on-camera flashes. We all agree that there is no direct equivalent between a guide number and an output in Ws (or Joules). Besides, the rating in Ws is misleading in that it only refers to what energy the capacitors can store (disregarding the efficiency of the tube and reflectors) and the guide number is also misleading, being measured in a relatively small white room, so that reflections on the walls contribute... a problem when trusting your guide number outside.

The only real way to compare from a photographers point of view would thus be to mount a camera and a studio in the same softbox and see what happens. The Internet being what it is, somebody has already done that here. The answer is that a Nikon SB-800 compares to a 92 to 133 Ws studio flash. A rule of thumb of 100 to 120 Ws for a large on-camera flash thus appears reasonable.


There is one little on camera flash with a rating in Ws, the discontinued Sunpack 120J. It had a rating of (surprise!) 120Ws, a bare bulb and electronics which are not bigger than the one of a typical large on-camera flash, so it is technically possible to get this rating for these kinds of electronics.