If you're looking to make photos with good light and you're using a point and shoot, your options are limited. If your point and shoot has a flash hot shoe then you have something to work with, but if not then you're sunk. Right? Maybe not. If, like me, you're a fan of David Hobby's site but you don't have a dSLR then read on.
Being creative with off-camera flash is easy enough if you have a dSLR with tons of functions and a commander mode etc., but not so easy if you're using a point and shoot. However by choosing your settings correctly and picking the right flash you may have some luck.
First a little background. Triggering external flashes can be accomplished by several different methods:
Electrical connection with a wire:
This won't work with most point and shoots because they don't have the required hot shoe or pc connector.
Preflash communication between camera and flash:
(Nikon CLS for example) This won't work with a point and shoot because they don't have the required electronics to perform this communication.
Simple optical slave triggered flash:
This is when an external flash is triggered by the burst of light it sees from another flash, and this is what you can use with your point and shoot, but only under certain circumstances. Here's why:
In most modes when your point and shoot fires its flash it actually fires it twice. The first flash is called a preflash and allows the camera to take some measurements before opening the shutter and firing the "real" flash to make the exposure. The problem with using your P&S flash with a slave trigger is that optical triggers trip the external flash when they see another flash pop, usually with no logic other than that. This means that the remote flash will be triggered by your camera's PREFLASH, and probably not by the main flash occurring a brief time later. This means your off-camera flash will fire, but only before the shutter is open. It will not contribute to the exposure.
There are of course, ways around this. The first is to buy a programmable or smart optical trigger, which has the built-in logic required to ignore the preflash and fire the slave at the correct time. That's not what this article is about though, this article is about using simple equipment - in this case the equipment I already had.
The first setup:
The first thing I tried was a Vivitar 2800 and an old Braun optical trigger. I triggered it with a Canon Powershot A70 in manual mode with the on-camera flash set to its lowest power level. Manual mode cancels the preflash, and lowering the power limits the amount of light from the on-camera flash. This setup worked fine - the external flash triggered at the right time.
Next I tried triggering it with the Canon SD430 which doesn't have a manual setting and doesn't allow you to turn the preflash off. My experience with this setup was that the Braun trigger would fire the Vivitar on the preflash but not the main flash, and the 2800 would never contribute to the exposure. This means that this setup will only work with a camera on which the preflash can be turned off. The fact that this combination wouldn't fire again a split second later with the main flash could have been a limitation of the external flash or of the optical trigger, I couldn't say from this test.
The other option I tried was just a Nikon SB-800. Happily, the Nikon SB-800 includes its own optical trigger activated by putting the flash in SU-4 mode. The good thing about the SB-800 is that in my testing its response is so quick that it flashes on both the preflash and the main flash of a point and shoot, therefore contributing to the exposure. If the SB-800 dumps out a lot of power however, I would expect that it wouldn't be able to recycle in time to pop along with the main flash, so this is probably only appropriate for low power settings. This is probably the best method to choose if you have a point and shoot which doesn't allow you to turn off the preflash.
Here you can see both flashes shot with the SD430. The SB-800 is firing for the second time and synching with the on-camera flash, but the Vivitar only fired once with the preflash and not during the exposure:
Here are both flashes shot with the A70 in manual mode (no preflash). Each flash fires once, in synch with the on-camera flash and the shutter.
Whichever method you choose, one thing to keep in mind is that you want to be able to control the amount of light coming from the on-camera flash. If you can control the output level of the P&S flash this may help. If you can't control the flash level or if you can't turn it down enough, then you might want to deflect or diffuse the builtin flash somewhat with a piece of paper. I used a small piece of white paper taped to the front of the camera at about a 45 degree angle. It effectively bounced the flash up to the ceiling and kept it out of the picture. (but still allowed triggering of the remote flash)
How to do it:
With an SB-800 (SB-900 probably similar)
-Put the SB-800 in SU-4 mode and position it.
-Turn on the flash on your P&S, set it to manual low power if you can.
-Tape a piece of paper over your on-camera flash to keep its light out of the picture.
-Vary the manual level of the SB-800 until your exposure looks good.
With an other flash and optical trigger:
-Attach the optical trigger to the flash and position it.
-Set the camera in manual mode and set the flash to its lowest output. (or cancel the preflash by whatever other method your camera offers.)
-Vary the level of the flash if it offers manual control, if it's an automatic flash you might need to adjust its position to get the correct exposure. Placing filters (polarizing or coloured) over the flash's return light detector will cause it to increase exposure. Play around with it.
All this still left me with the question of whether the Vivitar's failure to fire twice in quick succession was the fault of the flash itself or of the optical trigger. So I hooked up the trigger to the SB-800 (in manual mode this time, not SU-4 mode) and tried that with the SD-430 including preflash. It fired twice, fast enough to be caught by the shutter, proving that the trigger responds fast enough, and the problem was with the Vivitar flash. I suspect this means you could use a simple optical trigger with a more modern flash like the SB-600 which doesn't have SU-4 mode.
The SB-800 firing with the Braun trigger:
For me, the right flash is the Nikon SB-800. This will give you the best results, but any flash unit may work as well as long as you pair it with an optical slave AND your camera has a manual setting or allows you to otherwise turn off the preflash.
So what do you do with this? Well with an off-camera flash (and an umbrella) you can turn this:
Canon A70 using built-in flash
Canon A70 with off-camera Vivitar 2800 and optical trigger
In fact you can do much better than this. The point is that you can get creative with what you have, you just need to experiment a little. You don't necessarily need to spend a ton of money to get fun results. In this case the camera that worked better was an older model that most people would probably be trying to upgrade. Oh - and it syncs at higher shutter speeds than most pro SLRs do.