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Elinchrom D-Lite RX 4 or Bowens 400Rx
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<blockquote data-quote="WayneF" data-source="post: 383724" data-attributes="member: 12496"><p>I read the Bowens 400RX spec as saying GN 262 (feet), GN 80 (meters). However, this would be true of maximum power with the furnished bare reflector, not likely how it will be used. If you put an umbrella or softbox on it, it would be a very new situation (lower output). And hard to measure distance than, so normally, light meters are used to determine exposure instead of GN.</p><p></p><p>Guide Number is distance * fstop. So GN 60 (meters) means at 1m, the proper aperture would be 60m / 1m = f/60. Or 60m / 6 m = f/10, or 60m / 10 m = f/6, etc.</p><p></p><p>If full power GN were 60, then at 5 stops down (1/32 power), new GN would be 60 / (1.414^5) = GN 10.6 (meters). This would mean at 1 m, then GN 10.6 / 1m = f/10.6. But the spec I see seems to say GN 80 (meters), GN 14 at 1/32 power, which is only true if using the furnished bare reflector.</p><p></p><p>Again, umbrellas or softbox will discard the GN for some new lower one.</p><p></p><p></p><p>You said very small space, and you said 400 watt seconds. I think you will find that to be excessive power. These turn down to 1/32 power, but in a small space, you will always be running them near minimum, 1/16 anyway, or maybe less. Such lights are their slowest longest duration at low power, and also their reddest white balance. I think there is advantage of a smaller light operated higher on its range. A normal speedlght is near 75 watt seconds, for example (which is quite a bit of light, esp in small space).</p><p></p><p>I use a 160 watt second Alienbees in a Large (40 inch) softbox, not more than three feet from the portrait subject (for maximum softness), turned down to about 1/8 power, and shoot at f/8 to f/10 at ISO 100. </p><p>A double power unit would simply have to be turned down to 1/16 power (which I find excessive). I wish I could buy a 80 watt second light (like a speedlight), but built like the studio light (AC, recycle, cooling, open flash tube, modifiers, etc).</p><p></p><p>High power is used for greater distances, large spaces.</p></blockquote><p></p>
[QUOTE="WayneF, post: 383724, member: 12496"] I read the Bowens 400RX spec as saying GN 262 (feet), GN 80 (meters). However, this would be true of maximum power with the furnished bare reflector, not likely how it will be used. If you put an umbrella or softbox on it, it would be a very new situation (lower output). And hard to measure distance than, so normally, light meters are used to determine exposure instead of GN. Guide Number is distance * fstop. So GN 60 (meters) means at 1m, the proper aperture would be 60m / 1m = f/60. Or 60m / 6 m = f/10, or 60m / 10 m = f/6, etc. If full power GN were 60, then at 5 stops down (1/32 power), new GN would be 60 / (1.414^5) = GN 10.6 (meters). This would mean at 1 m, then GN 10.6 / 1m = f/10.6. But the spec I see seems to say GN 80 (meters), GN 14 at 1/32 power, which is only true if using the furnished bare reflector. Again, umbrellas or softbox will discard the GN for some new lower one. You said very small space, and you said 400 watt seconds. I think you will find that to be excessive power. These turn down to 1/32 power, but in a small space, you will always be running them near minimum, 1/16 anyway, or maybe less. Such lights are their slowest longest duration at low power, and also their reddest white balance. I think there is advantage of a smaller light operated higher on its range. A normal speedlght is near 75 watt seconds, for example (which is quite a bit of light, esp in small space). I use a 160 watt second Alienbees in a Large (40 inch) softbox, not more than three feet from the portrait subject (for maximum softness), turned down to about 1/8 power, and shoot at f/8 to f/10 at ISO 100. A double power unit would simply have to be turned down to 1/16 power (which I find excessive). I wish I could buy a 80 watt second light (like a speedlight), but built like the studio light (AC, recycle, cooling, open flash tube, modifiers, etc). High power is used for greater distances, large spaces. [/QUOTE]
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