Monday, 7 June 2010

Off Camera Flash - Tutorial Quickie

Not too long ago I posted a review of the Think Tank Photo Hydrophobia 300 - 600 all weather rain & elements cover for DSLR cameras with a long telephoto lens attached.


I couldn't resist creating my own rain for the shot and persuaded my long suffering wife hold the water source! And before you ask, there is a real camera & lens inside the cover, that is how much faith I have in the product being tested.

How to do it
This shot is very simple and took little time to execute. I used two remotely triggered Canon 550 EX Speedlites fitted with Gel Clips and Rosco Strobist Collection CTO (Colour Temperature Orange) correction gels. The shot was set up in my outside in my back garden with the camera white balance set to tungsten or incandescent which gave the blue element to the image. The rear light was corrected with one layer of CTO to create a neutral light, whilst the front right light was corrected with CTO to correct the daylight flash to tungsten/incandescent with an extra 1/2 CTO to add more orange to the light.


Both lights were snooted with Rosco matte black Photofoil to control spill. The flash units were triggered with inexpensive radio triggers bought on Ebay - OK, so they're not Pocket Wizards, but they only cost about a tenth of the price! The flash units were set to manual rather than e-TTL. This gives you more control over the scene and can conserve battery life.

As you can see, this is a very simple set up with the ambient daylight under exposed by 1 stop to give me what is effectively my third light source. The light at left provides separation from the background whilst the light to front right give shape to the product. Remember that light illuminates whilst shadows define.

I don't recall the flash power settings. I guess they were around 1/8th or 1/16th power for both lights. I could have made the background darker by using a faster shutter speed, but that would mean less blue light creeping in. The flash were each about 6 feet from the subject. Using a low(ish) power setting on the flash gave a short flash duration which froze the water droplets. The blue blur is a result of dragging the shutter at 1/160th second. A slower or longer shutter speed, say 1/30th second would result in more blur but over expose the image for the flash working aperture of f5.6. Had I stopped the lens down further, the background would have appeared too sharp or in focus.

The eagle eyed among you will have noticed that the blur is below the frozen water droplets, this is because the flash fired at the end of the shutter exposure. Had I set the flash to fire on First Curtain Sync, the blur would be behind the water droplets and appear more natural. First curtain sync triggers the flash at the beginning of the exposure. Most cameras by default fire the flash at the end of the exposure, well at least my Canons do.

TTFN

Ian

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