I Need Power
Just imagine you are considering buying a new car. But which is the right one for me? How much power do I need? Do I need a lot of room, or will a compact model do? While surfing the Internet, the decision is reached: it should have POWER! And of course plenty of storage space for my complete photographic equipment. You quickly find a car model with a power of 200, and a 1200-litre luggage compartment.
But your enjoyment doesn’t last long. When you look more closely, it becomes clear that the figures have almost nothing to do with the real performance, or have been inflated by marketing to make the desired impression. Clearly it is possible to achieve a luggage compartment capacity of 1200 litres, but only when the rear seat is removed. Is this a real value which allows a potential customer to compare different brands and models? The nominal power is correctly stated as 200, but in which units? Are we talking here about kW (kilowatts) or bhp (horse power)? How can the customer decide when he does not even know what the manufacturer is talking about?
Using this as a metaphor for the fundamental problem of flash duration value t0.1 or t0.5, the situation is this:
Should I purchase a flash unit that on paper achieves an unbelievable t0.5 figure, but which has nothing to do with real working conditions (rear seat removed)? Or even worse: an unbelievable figure is quoted but the units t0.1 or t0.5 (kW or bhp) are nowhere to be found. Very clearly not!
For correct exposure the t0.5 value is crucial, but the remaining light (40 per cent) has a big influence too, which may make itself felt in the blurring of motion in a photo.
with t0.5
with t0.1
The solution is obvious…
Comparisons are not worth much as long as we are comparing apples with pears, and, from a photographic point of view, t0.5 is only half the truth. Anyone who needs to know whether a flash unit can provide fast flash durations looks at t0.1 and nothing else! Anyone who compares the various manufacturers with each other will question how the measured times were arrived at. Or even better: you take a test drive to convince yourself of the power and capacity…
Photograph by Lawrence Mak
Lawrence Mak – is Hong Kong base commercial photographer and build up his own professional studio “Lawrence Studio” since year 2003. Lawrence is specializes professional photography in fashion and commercial print ad. Most of print ad. show at MTR, bus and magazine. Also, provide wide range of photography service like pre-wedding photography and photography Course.
