Cactus V6ii tests

All my current Cactus V6ii tests with two TTL-flash units are available in the this presentation.

Using two TTL-flash units – for key light and fill light - is not straight forward. Finding the right balance is difficult and is – at the end of the day – a matter of personal preferences. The TTL-flashes are controled by a sensor in the camera, which utilizes advanced light metering. The sensor cuts off the flash light, when it's sufficient for a proper exposure. As opposed to old fashioned A-mode flashes, with one sensor in each flash unit, the TTL-flashes won't cut off each other, but still – if the power of one flash is increased, the other will flash will contribute less to the final exposure. Furthermore, the angle of the light, relative to the subject and the camera, the brightness of - and distance to - the background etc. will eventually play i part in determining the final amount of flash light for the exposure. The two flashes must be balanced, in order to provide a pleasant lighting of the scene.

I have often read, that the power of the fill light, set at –2 stops, which apr. equals a 25% output, is prefered by many photographers. However, my TTL-flash tests seem to indicate that 2 stops probably is too much, when using TTL-flashes. I have a portable strobe outfit - Elinchrom Quadra - that comes with a fixed balance, between the two strobes, at 100% and 33%, which equals 1½ stops.

The best results – in my tests – were achieved by increasing the key light and decreasing the fill light. A difference of 1½ stops seems just about right. Furthermore I found, that using a small negative exposure compensation in the camera, will help avoiding burned out high lights.