This time was the same, but different. On the JetBlack 24hour mountain bike event, the conditions were poor, but the expectation of results was high. Due to the continual rain I had to shoot at ISO1600 all day and sadly the aperture was low at f4-f5.6 for most of the day. this meant using flash for basically the the entire event.

I had to cover the race start, and 6 locations in 8 hours, so being mobile was very important. I was on the MTB course in difficult locations in rainy and muddy conditions so everything had to be rain-proof, and able to work all day without interruption.
To achieve this I used the Canon 580EX with a CP-P3 battery pack (both inside zip-loc bags), a mini tripod and clamp mount, and my “custom” 15 Meter off-shoe cord.

As the flash is closer to the subject, and using ETTL, it works as if it was on your hot-shoe, but saves power, batteries, melt downs etc….

The idea behind this, is that the flashes output power Guide Number (GN) is a function of aperture and distance to the subject (GN = distance × f-number). Lets pretend GN is basically flash power. To use this set-up all day you need the flash to use low power all day. Your aperture (f-number) is set as part of your main exposure (In my case it was ISO1600 f4-f5.6 and shutters from 1/800 to 1/10 for the arty shutter-drag shots).
To keep the power as low as possible all day, I have moved the flash closer to the subject, meaning it needs far less power to illuminate the subject than if the flash was on the camera.

I know the flash is in a stream….it wasn’t when I started!!!

Other benefits of this set-up is that you can have the flashes almost anywhere. The photo below, the flash was in a tree over my left shoulder. The same principles apply with ETTL sending it’s pre-pulse and then firing…..only the flash is off the camera.

With the saving in power, I had 660 odd shots from one CP-E3 and one set of flash batteries. Makes a wet day far easier if you don’t have to change batteries!!!

As always there is a down side. I was lucky with this event that the competitors were spread out. The 580 does have the ability to melt down if you drive it too hard. While this set-up will save power, I’m not too sure how it would go if you have lots of shots close together. We’ll see later I guess…