Using the Built-in Flash of your D-SLR ( Part III)
In Part II ( SP, March2012) of this series you saw how you can build a multi-flash setup using dedicated strobes. This article will guide you on how to do a similar set up using non-dedicated strobes. The main advantage of non-dedicated strobes is that they are very inexpensive. If you compare two strobes, one dedicated and one non-dedicated, with same guide number, the cost of the latter will be only about 20 percent of the former. This is quite a compelling reason. Plus, since they are non-dedicated they will work even if you change your camera brand!
Here is one precaution that you must take. Never connect (either on a hot shoe or through a PC cord) a nondedicated strobe on your precious D-SLR as it may fry the electronics of your camera due to incompatible trigger voltages. If you have to connect a non-dedicated flash, use a device called Safe-sync which will reduce the trigger voltage to acceptable levels and thus prevents any damage to your camera. However, a non-dedicated strobe can be used perfectly safely with your D-SLR, if your camera’s builtin flash is used to trigger it remotely. In principle, this is how a non-dedicated multi-flash setup operates. Your D-SLRS built-in flash sends out a pulse of light when you press the shutter release. This light pulse will be detected by the optical sensors of the slave strobes and they will in turn fire. However, there are many other variables that come into play. As you read through the rest of the article, you will learn how to build a nondedicated multi-flash setup and trigger it using your D-SLRS built-in flash. Due to the non-dedicated nature of the strobes you will not have the following features:
No TTL or any other type of automation. Only manual operation is possible. No modelling function. Susceptible to false triggering (that is, your strobes may get triggered by someone else’s flash and you may similarly, but unintentionally trigger someone else’s strobes).
No remote operation. You need to go near the slave strobes to adjust the output level. Let us look at some of the features your D-SLR built-in flash and strobes must have inorder to use it in such a setup.
First and foremost, your camera’s built-in flash should operate in manual mode. Cameras that have this feature are – Canon 7D, 60D and 600D and all Nikon DSLRS with built in flash.
It will also help if your camera’s builtin flash has variable power in manual mode as you can adjust the output level to what you want, to fit in the overall lighting scheme apart from just triggering the slave units. Variable power will also help to set the built-in flash to minimum output level in case you are using it to just to trigger the slave units but not as a part of the overall illumination.
Your slave strobes themselves should also have variable power output. You will also need a tripod adapter in case you want to mount the slave on a tripod for easy positioning of the slave ( Picture 1).
The slave strobe must have an optical sensor to sense the light pulse from your built-in flash and fire. If it does not, then you need to buy an external optical sensor and mount the strobe on it. ( Picture 2)
The slave strobe should have a tilt swivel head. The optical sensor of the slave strobe should face and have a line of sight view with the built-in flash of your D-SLR for proper triggering. Hence, having a tilt swivel head on the slave strobe will greatly simplify the positioning of the slave.