↓Skip to main content
  1. Classic threads/

Portable studio lighting: battery strobes on location

·5 mins
Lighting People Gear talk

This was a popular thread on the old Hellophoto forum, and we’ve rewritten it from scratch as a general guide (no brand reviews, just how the kit works).

The idea is still brilliant: near studio-strength flash, run off a battery, used on a beach or a farm track with no power point in sight. Battery strobes in the 400 to 600 watt-second class let you overpower the sun and shape light with proper modifiers.

Watt-seconds vs guide number

These two numbers get mixed up all the time.

Watt-seconds (Ws) describe the energy stored in the flash’s capacitor. It’s a measure of what goes in, not what comes out. Two 600 Ws heads can put out noticeably different amounts of light depending on the flash tube, reflector and electronics.

Guide number (GN) describes how far the light reaches. It’s quoted for a given ISO (usually 100) and a particular reflector, and you can use it to work out aperture: divide the guide number by the distance in metres and you get the f-number for a correct exposure. Change the reflector and the guide number changes too.

So when comparing units, compare guide numbers at the same ISO and with similar reflectors, and treat watt-seconds as a rough class rather than a precise ranking. Better still, borrow a light meter and test.

Why the extra power matters outdoors

A speedlight is fine indoors, but outside you’re competing with the sun. To get a darker, moodier sky behind your subject you need to underexpose the ambient light, which means a small aperture, a low ISO and the fastest shutter speed your flash sync allows. Then the flash has to light the subject at that small aperture, often through a softbox that swallows a stop or more. That’s where a few hundred watt-seconds earns its keep.

Sync speed and high-speed sync

Most cameras with a focal-plane shutter have a maximum flash sync speed somewhere around 1/160 to 1/250 of a second. Go faster and part of the frame is blocked by the shutter curtain when the flash fires, giving you a dark band.

High-speed sync (HSS) gets around this by pulsing the flash rapidly for the whole time the shutter slit is crossing the sensor. It lets you shoot at 1/1000 or faster for wide apertures in bright sun. The catch is a big loss of power, commonly a couple of stops or more, and it gets worse the faster you go. HSS needs a compatible trigger and flash for your camera system. The alternative is an ND filter on the lens, which lets you stay at normal sync speed and keep the full flash output.

Recycling time

After a full-power pop, the strobe needs time to recharge, typically a second or few depending on the unit and battery state. At lower power, recycling is much quicker. For portraits with expressions that change fast, shoot at half power or less and open up the aperture a little rather than hammering full power and missing moments.

Modifiers that travel well

  • Umbrellas are light and cheap but catch the wind like a sail.
  • Softboxes and octaboxes give nicer, more controlled light. Collapsible designs set up quickly.
  • Beauty dishes give crisp, punchy portrait light and handle wind better than umbrellas.
  • Bare reflector is the most efficient option when you’re fighting bright sun.

The bigger and softer the modifier, the more light it eats. Keep that in mind when choosing between a giant octa and the power you’ll have left.

Stands, sandbags and wind

New Zealand wind is the enemy of location lighting. A light stand with a softbox on top is a lever waiting to tip.

  • Use a sturdy stand with a wide footprint, and keep the head as low as the shot allows.
  • Hang a sandbag (or a bag of gear) from the stand or lay it across a leg. Every time.
  • Have a person hold the stand if it’s gusty. Assistants make great ballast.
  • Point umbrellas and softboxes edge-on to the wind where possible.
  • Check the MetService forecast for wind before the shoot and have a plan B for a smaller modifier.

When you’ve got people on set, a falling stand is a genuine safety issue, not just a gear issue. WorkSafe has general guidance for anyone working professionally with equipment around clients.

Battery care

The lithium battery packs in these units are powerful and need a bit of respect.

  • Charge them before a shoot and don’t leave them sitting fully flat for long periods.
  • For long-term storage, a partial charge is generally kinder than full or empty. Check the maker’s instructions.
  • Keep packs out of hot cars and direct sun.
  • Inspect for swelling, cracks or damage. A puffed battery should be retired safely, not used.
  • If you fly with gear, spare lithium batteries generally have to travel in carry-on rather than checked luggage, and larger packs may need airline approval. Check your airline’s rules before you pack.

Putting it together

A good starting setup: one strobe in a medium softbox at 45 degrees, sandbagged stand, sun behind the subject as a rim light, aperture set to darken the sky. For locations worth lighting, try our golden hour spots.