Studio strobes power demands

Hello,

I'm planning to equip small photo studio. It will be used mostly for portrait photography. Available room dimensions are 18x12x8 feets (5.5x3.5x2.5 meters).

The choice of studio strobes will be probably Bowens Gemini kit + some additional modifiers like softbox and beauty dish, however, I don't know if 200rx or 400rx will be better suited for this small space? I'm afraid of possibility that 400W/s strobes could be too powerful on minimum power setting for shooting at ISO 200 and apertures around f/4-f/8? What do you think? Then again if I choose 200W/s strobes could they be too weak for using with big softbox as key light and closed down aperture to f/11 or little bit more?

What would you recommend?

Many thanks!

with indoor studio... why shoot at ISO 200 if you think your strobes are too powerful?

fashionrider wrote in post #16897545
with indoor studio... why shoot at ISO 200 if you think your strobes are too powerful?

Because I want my Nikon bodies also be usable

coldplug wrote in post #16897589
Because I want my Nikon bodies also be usable

I'm still confused. Why can't you shoot at ISO 100?

Native ISO of Nikon starts at 200 if I'm not mistaken. Same with the Fuji X series.

coldplug wrote in post #16897420
I don't know if 200rx or 400rx will be better suited for this small space? I'm afraid of possibility that 400W/s strobes could be too powerful on minimum power setting for shooting at ISO 200 and apertures around f/4-f/8? What do you think? Then again if I choose 200W/s strobes could they be too weak for using with big softbox as key light and closed down aperture to f/11 or little bit more?!

"It depends!!!"

• What light modifier you choose will influence the degree of light attenuation compared to a standard reflector.
  
• What angle of coverage is provided by the reflector will influence the brightness of coverage.

• My Dynalite M500 power pack dialed down to 62 w-s for a single head in a 24"x36" softbox at 4', it reads f/5.6 at ISO 100 or GN56.
  
• Two heads on a single channel (net 31 w-s each) would result in f/4 from each head in a softbox at 4'!(1/8 power), with two heads on a single channel (net 31 w-s each head) would result in f/4 from each head in a 24"x36" softbox at 4' distance (GN16)!
  
• In comparison, my own measurement with Minolta Autometer Vf shows that my Dynalite M500 (500 w-s) into 140 degree coverage reflector head (no softbox) when dialed down to 1/8 power the same head would result in f/12 at 4' or GN47

Wilt, from your experience it seems that better idea would be 200W strobes! This is what I expected also. Let's see if there are different opinions?

Many thanks all!

And yes, some Nikon bodies won't go below ISO 200, that's another reason to use less powered strobes.

coldplug wrote in post #16898385
Wilt, from your experience it seems that better idea would be 200W strobes! This is what I expected also. Let's see if there are different opinions?.

A significant factor in a choice is how many levels of power you can dial down the light! If you start with 500 w-s,

• 500-250-125-62-31 is 5 levels of power
  
• 500-250-125-62-31-15-7 is 7 levels of power

• start with 500 w-s and use 6 levels of adjustment, or I
  
• start with 250 w-s and use 5 levels of adjustment,

You could always throw on a Circular polarizer to knock the power down a stop.

Wilt wrote in post #16898958
A significant factor in a choice is how many levels of power you can dial down the light! If you start with 500 w-s,

• 500-250-125-62-31 is 5 levels of power
  
• 500-250-125-62-31-15-7 is 7 levels of power

So if I needed very low level of power, I could

• start with 500 w-s and use 6 levels of adjustment, or I
  
• start with 250 w-s and use 5 levels of adjustment,

...and both have the same final ouput on the scene.

we are back to "It depends!"

Also. 'pro' equipment often only comes as low as 400-500 w-s, and have powerful enough modelling lamps (>150 wwatt) to be able to use them in bright ambient conditions,
while 'hobbyist' equipment (and 250 w-s) comes with somewhat anemic modelling lamps (<150 watt) that are washed out and useless for seeing light placement effects in bright ambient conditions (living rooms with big bay windows)

Sure, I know. Bowens Gemini has 5-stop difference between max and lowest output. Unfortunatelly professional equipment is for now out of budget reach. Modelling lamps inside those monolights are 250W, it seems enough for that job.

Gonzogolf, that also seems like good idea. So, I'm again far from decision, 200 or 400

I rarely use modeling lamps unless, for some reason, I am shooting in a place that absurdly dark...


Many people shoot with MUCH more power than you are indicating you are worried about. I would focus on the craft.

MORE POWER! You modifiers will cut down the output of your lights and you can always knock down power with an ND filter. I would recommend having grids or eggcrates for your modifiers, as well as internal baffles.