Normally you need for outdoor photography mostly true portable flash units, the (usually more than 800 Ws) are equipped with their own power supply and a correspondingly high power. Regardless of the crisp cost of such installations is mostly drags around a fairly weighty investment with it, which also presupposes precisely Setplanung, since one such scenarios not even just up and degrades.
However, if you do not want to necessarily expose to the sun, are my experiences with two 580EX II and light shapers of Lumiquest and flash2softbox inspiring. The 580EX II have enough power to illuminate silky smooth with corresponding softboxes half portrait shots. It only pulls out the wide-angle diffuser, is the lightning to the desired soft boxes and thanks to E-TTL2 and the wireless infrared controller are in a very short time very homogeneous exposed photographs the result.
However, I recommend the advanced amateurs, to dispense with the E-TTL exposure control conscious and flashes with a wireless trigger (eg Pocket Wizard or Skyport) trigger in manual mode. On one hand, you then have complete control over the amount of light - on the other hand Zuverlässsigkeit and range of the radio transmitter / receiver for outdoor use is significantly higher than the infrared control of the ST-E2. Last but not least, you can perfectly adjust the shutter speed and aperture of the camera in M mode to the circumstances.
Conclusion:
Positive is the enormous mobility and flexibility, the absence of a separate power supply and the abundance of light modifiers such as softboxes, spots, barndoors, etc., as well as the universal application on-location.
Negative is the available quantity of light - of course it does not come close to a real Porty system and the use is limited to half-portraits. Although whole-body images are quite possible - but only with stripe softboxes and several 580EX II, which then significantly drive the cost up. In addition, the system of course the coveted modeling a real Blitzanlage missing. In order to be well-positioned hair and top lights to try and error game - thanks to digital photography but not a real cost factor.
Indoor there is an almost perfect solution - Outdoor you should think seriously about art Funkauslöser and manual flash control in spite of available E-TTL. The flash is so universal, that the serious amateur to be given every opportunity to flash unleashed in high quality.
I'd almost always prefer a system of 2-3 580EX II portable systems.
