After I put Elliot down to bed tonight, I got a bit bored, and decided to do my best David Hobby impression, though I replaced the Mountain Dew with a wonderful bottle of vin rouge (eagle-eyed readers will notice the red ring symmetry, courtesy of my 85 f/1.2L mkII on the left)

The setup here is really deceptively simple.  A 580EX sitting on the keyboard of my MacBook Pro, and a 550EX on a lightstand at camera left, at a 45 degree angle to the back wall.  Both flashes were triggered by Pocketwizard Flex TT5s, with a PW Mini TT1 and AC3 in the hotshoe of my 5D Mark II.  Lens was the Sigma 50 f/1.4 at 1/20, f/6.3, ISO 100.  Camera and lens held steady by an Induro CT-213 carbon fibre tripod and Manfrotto 498RC2 ballhead.

I wanted a nice swath of blue in the background, so I gelled the 550EX with a single cut of CTB (colour temperature blue).  However, I found that this wasn’t giving me the rich, saturated blue that I was looking for.  I added a 1/2 CTB to the 550EX, giving me a total of 1 1/2 CTB, but this still wasn’t really what I was looking for.

The solution was to set the camera’s white balance setting to tungsten, which makes neutral white light look blue, and thus makes blue light look…well…really blue.  This gave me the blue I was looking for on the back wall, but made the neutral white light from the 580EX on the keyboard go too blue.  To get around this, I simply gelled the 580EX with a full cut of CTO (colour temperature orange), to correct for the tungsten white balance.

You’ll notice that one side effect of the tungsten white balance is that the white light from the Apple logo on the back of the MacBook Pro is pushing heavily toward magenta, as is the label on the wine bottle.**

This is a shot where I really wish I had a third Speedlite, which I would have used to illuminate the MacBook Pro.  As it stands, you can barely make out the outlines of the screen.  Oh well.  I sold my 580EXII to buy the Fuji X100, and I’m 100% satisfied with that deal, so I’ll just have to live with two Speedlites for the moment.

Anyway, this shot is a good example of how creative use of gels and white balance can radically transform what is possible with off-camera lights.

** – EDIT: This morning, I realized that I had processed this image using the public beta version of Lightroom 4, which offers localized white balance corrections using adjustment brushes.  So I went back and edited the white balance of the Apple logo, to make it more white.  I also boosted the exposure of that region.  A minor change, but an important one, I think.