How Much Power?
The amount of flashpower needed depends on the nature of what you will be shooting
. In evaluating this, the important considerations are:
- the distance from the light(s) to the subject(s)
- the size of the subject and shooting environment
- the desired aperture range and the ISO speeds involved
For small studio portraiture, these parameters are fairly known. You should always shoot at the lowest ISO settings available from your camera (typically ISO100, but some cameras limit you to a minimum ISO of 200). If you are limited to ISO200, you will need half as much power as ISO100 cameras, but your results will not be quite as good in terms of noise and general quality.
In most small portrait studios, the photographer will want to be able to shoot from one to three or four people at apertures ranging from f4 to f16, using umbrellas and softboxes at distances of two feet to eight feet or so. Studio flash units rated from 150 Ws to 300 Ws each (or more) provide ample output for this purpose. It is extremely important that your flash units have a wide adjustability of power levels. A 5 f-stop adjustment range (from Full Power to 1/32 power) is ideal. Of course, it is very important to have flash units with accurate modeling lamps so that you can compose your pictures and avoid excessive trial and error.
>> Click Here for more info on Studio Flash Basics
If you are limited to ISO200, 300 Ws may be too much power because you may have difficulty in lowering the power enough to capture those f4 shots with close placement of the lights - particularly if you have a limited power adjustment range on your lights. If this is the case, you will be forced to move the lights further from the subject than you might prefer, or forced to use other methods such as Neutral Density filters to reduce the light levels.
>> Click Here for more info on Neutral Density Filters
Some users prefer to use lights with different power levels in such studios (i.e. a 320 Ws light for main and 160 Ws lights for fill, etc.), but many find this problematical and prefer to use three or four lights of the same power for easier interchangeability.
Our experience is that far more users end up wishing they had bought lower power lights
(i.e. the AlienBees B400
) rather than higher power.
>> Click Here for more info on the AlienBees B400 Flash Unit
The situation changes dramatically when you take your lights on location to shoot larger subjects such as wedding groups, location fashion work, architecture, etc. Here, you may need considerably more power
and may often be striving for higher aperture numbers. Most of these applications suggest flash units in the 600 Ws range. If your work regularly spans both small studio and location shots, the White Lightning X-Series X1600
units may be your best option as they are switchable from 660 Ws to 165 Ws and maintain a 5 f-stop adjustment range at either power setting, thus affording an overall range of from Full Power to 1/128 power.
>> Click Here for more info on the White Lightning X-Series X1600 Flash Unit
Beyond this, when even higher amounts of flashpower are needed
, combined with very fast flash durations and recycle times, the Zeus series
>> Click Here for more info on Monolights Vs. Power Packs
>> Click Here for more info on the ZEUS