Bowens 1000Pro, only 1 stop more than 400W ?

[luis_modesti]

<p> I just purchased a Bowens Gemini 1000Pro watts, (my first light with this much power). However, when testing against my Bowen Gemini 400, I only get between 1 to 1-1/2 stops more than what I get from the 400Watts light. Is this normal ?, is this what I am supposed to expect ? I was expecting much more than that in stops..... for such price...<br>

My test was performed with the same bowens reflector on both , at same distance of 10ft. (no light modifiers), only the standard reflector. I mettered with Sekonik 758 light meter (dome pointing directly at flash).</p>

<p>thanks for any insight.</p>

<p> </p>

[Charles_Webster]

<p>One stop up from 400 WS is 800 WS. To go to the next stop you need to double the power again to 1600 WS.</p>

<p>So yes, the 1000 WS strobe is only about 1-1/2 stops brighter than the 400 WS strobe.</p>

<p><Chas></p>

[luis_modesti]

<p>So Watts work in the same way as ISO and every thing else. ? interesting. I did not know that.... very expensive way of getting 1 more stop.... :-(</p>

<p> </p>

[Charles_Webster]

<p>I'm basing my assumption that a strobe having 800 WS of stored charge will actually produce twice as much light as one having 400 WS. But that is a widely-held assumption that most strobe power comparisons are based upon.<br>

<Chas><br /><br /></p>

[craig_shearman1]

<p>Charles is correct, assuming all else being equal. If two flash units of the same watt seconds have different reflectors, one could be out more light (if it's a tighter, more spotlight type of beam) or less (if it's a broader, more floodlight beam) than the other. If they are from different manufacturers, the flashtube in one might be more or less efficent than the other one. But generally speaking, you need to double the watt seconds to double the light, and each doubling euqals one f-stop.</p>

[rodeo_joe1]

<p>In theory a 1000 Joule flash ought to deliver just under 1 and one-third stops more light than a 400 joule unit of the same design. In practise it's probably closer to 1.5 stops because a more powerful flash is generally more electrically efficient. Not all of the charge in the storage capacitor(s) can get used - like not being able to get the last dregs from a soup tin, but a bigger "tin" tends to waste less soup or flash power.</p>

<p>BTW, Joules are the same as watt-seconds. Time was when flash makers commonly used joules to describe the energy capacity of their flashes. I'm not sure why it's been dropped in favour of the far more confusing watt-seconds or W/s designation. Watt-seconds are <em>not</em> the same as plain watts.</p>

<p> </p>

[luis_modesti]

<p>Just for the heck of continuing a conversation and not exactly out of ignorance, since I understand the principles, but why exactly would I want to spend close to a thousand $$ for one more stop of light. Isn't it more monetarily efficient to bump the ISO by one stop ?</p>

<p>remind me why I did spend that money ?</p>

<p>thx</p>

 

[Charles_Webster]

<p>I spent the money so I could shoot at lower ISO for less noise and smaller apertures for more depth of field. That said, I seldom need full power on my strobes and could often get by with the next size down.</p>

<p><Chas><br /><br /></p>

[ellis_vener_photography]

"Just for the heck of continuing a conversation and not exactly out of ignorance, since I understand the principles, but why

exactly would I want to spend close to a thousand $$ for one more stop of light. Isn't it more monetarily efficient to bump

the ISO by one stop ?

 

remind me why I did spend that money ?

 

thx"

 

Depending on what you do You may have wasted money. For what I do I find it is better to have power that I don't use

rather than not have it when I need it.

 

Generally I'd agree with you about the simply increasing the gain applied to your sensor's sensitivity but here's an

example when having that extra stop might make the difference:

 

You are working outside and to make sweeter looking light you have your light diffused in a soft box and for various

reasons you can't move it closer to the subject (inverse square rule in play). You also want a certain ratio between the

sunlit portion and the flash lit portion and because its a group portrait you need to shoot with decent depth of field.

 

Simply upping the sensitivity of the camera affects not just the brightness of flash lit portion but also of the sunlit portion

as well.