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I'm interested about buying an entry level studio lighting kit. I read very good reviews about Bowens Gemini 200 and 400.

When I do studio photography I normally shoot about 3-5 meters apart from the subject. Would the 200 model be sufficient or do I need the 400 (they both come with two monolight)?

mattdm
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zzzbbx
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1 Answers1

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The guide number of the Gemini 200 is 54m at ISO 100 for full power, so at f/8, you would need the strobe to be 6.75 meters away. The formula for this is:

GN = distance x f-number

So, from that you can work out your distances for the lights. Bear in mind that modifiers, such as umbrellas or softboxes, will reduce the light by some amount. You'll have to check the documentation that comes with them in order to be sure of the amount as there is no rule of thumb for that. However, lets say though, that it costs you a stop to have a bounce umbrella and you still want to shoot f/8. Then the a full stop lost from f/8 is f/11 (in other words, shooting with the umbrella is like stopping down to f/11 in light loss) and you would have formula:

distance = 54/11 = 4.9m

At any rate, I suspect you're fine with Gemini 200 as I'd be surprised if you got them up to full power in a close studio setting. You'll probably also do what I did eventually and buy yourself an incident light meter to get more accurate measurements.

Joanne C
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  • +1 - Just want to add that going to IS0 400 to double the ISO 100 guide number when needed on a modern DSLR/MILC is nothing like using ASA 400 "emergency" film in the 35mm cameras of my day. You still need a boatload of power to get the best out of medium format (smaller apertures are needed & ISOs from 35-50 are normal), but there's a lot of wiggle room in the small-format arena. –  Jun 09 '13 at 17:53
  • Great answer! Sometimes, I do not necessarily need two lights. Do you think one would be sufficient if I wanted to take a few shots with one light only (indoor)? – zzzbbx Jun 09 '13 at 18:34
  • @Bob - Absolutely, though shadows may be harsh. I think you'll probably have a lot of fun experimenting with combinations, modifiers, and reflectors. Lots of good information on that kind of thing here and on other sites. – Joanne C Jun 09 '13 at 18:36