Lights for Illuminating Large areas?

Question

I'm frequently underground in caves and recently while going on a trip to Thailand I experienced some of the most massive caverns I've ever had the opportunity to photograph. Unfortunately, I was ill prepared and my torches (about 1200 Lumens total) did not provide enough light in the end. Even on a 30 second exposure. Additionally, it was quite difficult to expose the background without over exposing the foreground.

I should also add that manoeuvring around a cave is by no means a simple task. Its no possible for me to run from one side to another with lighting equipment.

What can I do to get more even lighting across such a wide area?

Can I stack photos together to produce a good final result? I don't generally use flashes and just stick to using torches, Is this a good idea?

Below is a shot of a cavern I was in, its by no means the largest part (at its largest, its wide enough to fly a 747 through for several hundred meters:

Hope you can help.

Thanks!

Answer 1

There are few ways to achieve good results.

Most obvious one is to take few flashes with GN 58 or 60 (depending on a size of the cave you might need over 5 units). You put them around cave and make sample shot, see if it's fine, if not - re-adjust and shoot again. (don't be afraid to move your light sources around to get a best results, but be careful where you put them and where you step!)

If there's not enough light from a flash you take one unit, switch it to test mode, turn off flash control in camera body, fire the bulb exposition, then press test trigger two or three times releasing all flashes wirelessly at the same time. This way you'll get few full-power bursts what should be more than good enough to light up even largest caves. For this technique a flashes with Quick Shift Bounce are extremely helpful because you can direct them behind the obstacles without ever loosing connection to the master flash.

Another idea is light painting with powerful flashlight. Specialized units can go over 10 000 lumens. So you basically set your camera at long exposition (Bulb mode + remote control) and walk around the cave highlighting everything around. You just need to be careful about pattern and avoid pointing your flashlight towards camera. (note that if you expose frame for longer then several seconds everyone moving in the frame will be invisible, so you are free to walk around the scene moving your flashlight to cover all of the walls

Finally - A very long exposition can be used in most of the caves. As long as you can see something with your eyes after turning the torch off - you should be fine. Just set camera on tripod, and expose shot for required time (might be as long as few minutes! So come prepared). Though keep in might that you don't want to try this with low-end cameras (dark current can be a pain)

Of course - all of these assume you have a DSLR or a proper camera with bulb timer and can release flashes wirelessly (some of pro-oriented compacts can do that, or ILCs, still the DSLR is highly recommended, especially because of weather-sealing).

Answer 2

You can light paint with a flashgun much more effectively than with a torch (flashlight):

1. Get a cheap old manual zoom hotshoe flash, such as the Vivitar 285
2. Set the camera on a tripod, with a 30s shutter (you'll have to experiment to determine ISO/aperture).
3. Locate the furthest point in the scene from the camera (using a headtorch or similar) and aim the flashgun, zoomed right in and on full power.
4. Fire the camera and pop the flash a couple of times.
5. Zoom to the widest setting, lower the power and pop the flash in a couple of directions to light up the foreground.

With some experimentation you should be able to light up quite large areas with this technique. And you might get some interesting effects during the times when you don't get it quite right!

Answer 3

There is the "open-flash" technique, where the camera shutter is kept open while an external flash unit is fired in several directions or multiple locations, though moving the flash has to be done in darkness. This worked better with film than with digital cameras that accumulate noise.

The modern approach is to take mulitple photos from a tripod and overlay them with Photoshop afterward.

Also, flashbulbs are still being manufactured and large flashbulbs can produce more light than any portable electronic flashgun.