DV Info Net - Lux ratings and on camera lighting question...

The Sony HVL 20 is a 20 or 30 watt selectable filament light. It consumes just that, either 20 or 30 watts from the attached battery. That is not the brightness rating but the power consumption The brightness is usually measured in terms of lux or lumen value and must be specified at what distance form the light source the measurement is made. Your Sony light is rather a strong light BUT if you notice the beam angle on a flat white wall, you will see that it is rather narrow but bright. That is why it seems like a powerful light and if you do indeed measure the center «hot spot« area at 3 feet, you may get upwards of 1500 lux or 75 watt equivalent. The reason it is bright is that it produces a narrowish beam not unlike a flashlight. If the Sony "or whoever designed those 2 reflectors in that light to design the reflectors to spread out the light to a wider beam, then the lux rating at that same distance would drop to half or more. Many video lights today especially leds are notorious to give a high lux rating but NOT specifying the distance it was measured at, It would be easy for a led light to have 4 times the lux value if the distance is halved to 18 inches distance. That is why lux values at specified distance is important to determine an accurate brightness level, that is if they don't overrate the values, as most usually do. Getting back to the question if lux values are important, yes they are but only as a rough guideline and the real test is to try an actual unit on distances you generally use. The beam angle is very important as to not give a brighter center area. In general a led light or filament with 1600 lux or around a 75 watt filament equivalent is the minimum if distances of 15 feet or less are needed. of course, one can always up the gain on the camera but with gain comes the grain as they say. You should do fine with a 75 watt on the FX7.