Learn How to Setup Studio Lighting in 15 Minutes


Do you find studio lighting daunting? Understandable. When I got my first set of lights I played with it for half an hour. Intimidated and confused, I shoved it back in the box where it stayed for six months.

Don’t worry though, mastering exposure with studio strobes is easy; in fact it’s probably one of the easiest of the photographic skill sets. By following this tutorial, you can go from no experience with studio lighting, to getting a correct exposure on your first frame, without the aid of expensive and unnecessary light meters. This isn’t a crash course in complicated theories and physics; our goal is to get you using strobes and creating photographs as quickly as possible. You can return to the theories at your convenience. I am a firm believer in the idea that it’s easier to learn the why, when you’ve already figured out the how.

Warpaint john mcintire photography 0754 2

Getting Ready

Before we start, you’ll need to do a few things in preparation:

  1. Setup your studio strobe on its stand, set it to full power and make sure it works.
  2. You should know how to connect your strobe to the camera and make it fire by way of remote trigger, pc sync cable, slaved to your on-camera flash, or by way of an in-camera system. Refer to your manuals if you need help.
  3. Have your strobe’s instruction manual at hand.
  4. Settings: Set your camera to manual mode, your shutter speed to 1/125th of a second, and your ISO to 100. (If you have an older model, or a film camera, then default to 1/60th of a second.)
  5. Have a calculator at hand will make things easier.
  6. Finally, I recommend that you start to think in full stops, which I’ll cover in the next section.

Thinking in Full Stops

Most of our modern cameras are capable of setting the aperture in increments of 1/3 or 1/2 of a stop. This is extremely useful for fine tuning the exposure in most situations; however, for the purpose of this exercise, it is much easier to ignore them for now and concentrate on the full stop values as indicated in the chart below.


Finding Your Guide Number

The next step is to flip through your strobe’s manual and find where it lists the Guide Number (also check whether the guide number is listed in feet or meters; this is vital). This magic number is a rather complicated thing and steeped in the brain-wracking Inverse Square Law. As promised, you don’t yet need to know why it works; you only need to know how to use it at this point.

There are two main ways to use the guide number, that will be useful to you. You can choose your aperture based on the desired outcome of your photo and calculate where to put your strobe, or you can place your strobe for a desired lighting effect and calculate the correct aperture.

Calculating Aperture

Some lighting effects require strobes to be in certain positions, and distances from your subject and other strobes. In other circumstances, your strobe might be in a fixed position and it cannot be moved.

In these events, to calculate the aperture for a correct exposure all you have to do is measure the distance between the light source and your subject in feet or meters (whichever your guide number is listed as). Now divide your guide number by that distance. For example a guide number of 66 with a distance of 6 feet between your subject and the light source would result in: 66 divided by 6 for a result of 11. Your answer is your aperture for a correct exposure: f/11.

Most guide numbers never divide so evenly into full stops. For example, if you get a result along the lines of f/9.2, just round it off to the nearest full-stop for the moment and we’ll learn how to fine-tune the exposure shortly.

Calculating Strobe Distance

Conversely, if you know what aperture you want to use, for a creative effect perhaps, simply divide the guide number by your desired aperture. My tendency for studio portraits is f/8, so if you divide our previous example of 66 by 8 (66/8) you get 8.25. To get a correct exposure for this setup, you would just place your light source 8.25 feet away from your subject. It really is that easy.

One caveat: if you have a high powered strobe in a small place, you’re not going to be able to set your camera to something ridiculous like f/64. If your power output is too high, just turn your strobe down to half power and divide the guide number by two.

Fine Tuning Exposure without Changing Your Settings

As you learned, there are instances where you want your aperture to remain constant. You also don’t want to mess with the power settings on your strobe so much that they completely change your guide number and negate your ability to calculate your exposure with ease. Yet subjects move, or you might want to over or underexpose your image for creative effect. The way to do this is simple.

To underexpose or reduce the amount of light falling on your subject, you would move your strobe further away. If your light source is really close to the subject and you move it back about a foot, you will lose 1-2 stops of light (smaller f/number). If your source is farther away from the  subject and you move it back one foot, you will lose less light. This is caused by the Inverse Square Law which states:  In physics, an inverse-square law is any physical law stating that a specified physical quantity or intensity is inversely proportional to the square of the distance from the source of that physical quantity.  (and link to the wiki definition). Just know that closer in you lose more light as you back it away, than if the light is situated farther from the subject to begin.

This is also why I asked you to consider thinking in full stops rather than fractional increments. Moving a strobe or a model one or two feet is much easier to judge on the fly than the four inches (10cm) a third of a stop increment would require.

Notes on Modifiers

The most common modifiers in studio photography will affect the output of the strobe in terms of exposure. You may need to increase or decrease your aperture, or the distance of your light source, depending on which modifier you choose.

Soft boxes and white or translucent umbrellas, which all produce a softer, more diffused light, will decrease the amount of light falling on your subject. To combat this, choose a larger aperture (smaller f/number) or move your light source closer to your subject.

Beauty dishes, silver umbrellas and reflectors, which all produce a harder, more defined light, will increase the amount of light falling on your subject requiring you to choose a smaller aperture (larger f/number) or to move your light source further from your subject.

Modifierexamples john mcintire photography

If you choose to alter your aperture in these situations, feel free to revert to your 1/3 stop increments. A modifier will rarely alter the output of a strobe by a full stop.

You will quickly learn how your modifiers affect the output of your strobes and within a few sessions you should find yourself automatically compensating for them without thinking about it.

Putting it into Practice

I set up a quick portrait session to help demonstrate how to employ these techniques. Gemma graciously volunteered for the task.

The only preparation was the setup of a paper background and fitting the strobe with a beauty dish. After she arrived, I asked Gemma to stand two feet from the background and I placed the light source straight in front of her and as high possible with the beauty dish pointed downward at her face.

All that was required to start shooting was the correct aperture. The Bowens GM400 I used has a guide number of 76. I measured how far away the light source was; which was 7.5 feet. Dividing 76 by 7.5 gives a result 10.133. Because I was using a silver beauty dish, we know that I need to stop down the aperture to get a precise exposure so I set the camera to f/11 and took a test shot. As you can see from the histogram, these simple calculations gave me the correct exposure and it took less than a minute to get there.


In this image you can see that from the first frame to the last, the exposure remained constant leaving me free to concentrate on other aspects of the images.


Finally, here you can see the end result.

Gemma john mcintire photography 1692

I hope you’re still with me, and that I’ve convinced you that studio strobes are nothing to be afraid of. With a little practice, the techniques outlined in this article will quickly become second nature, allowing you to concentrate less on the technicalities of exposure, and more on aesthetic variables such as composition and establishing rapport with a client or model. As with most things, the key is practice. Snag a friend, a pet or even a bowl of fruit and run through the whole process again and again, until calculating the correct exposure becomes reflex, and you’ll find yourself spending more time and energy on the creative processes rather than the technical ones.

Read more from our Tips & Tutorials category

John McIntire is a portrait photographer currently living in the UK. He studied commercial photography at Leeds Metropolitan University. He is obsessive with photography and is always trying to learn something new. You can find him on Instagram as @johnwhitneyphoto for portraits and @macjw2 for landscapes and travel.

  • Michael

    Hi John! Thank you very much for the studio lightening tutorial. I read about it couple times in the past. However, it’s a little more than just dividing GNo either by distance to get the right aperture or dividing by aperture value to get the distance between the flash head and a subject. First you have missed the relationship between the guide number and the flash zooming setting. Second when I use modifiers and I always use them in my home studio, it takes more than 2 stops (between 2 and 3) to compensate the light lost comparing to unmodified flashes. I use small softbox for the key light and DIY bouncing panel for the fill light on my flash bracket. You mentioned that you set your ISO to 100 and your shutter speed to 1/125, didn’t it make your ambient very underexposed? I usually set my ISO at least 400 or more often to 800 so my background is not going too dark. I am trying to keep my ambient exposure between 1 to 2 stops underexposed and based on that I calculate my flash exposure. I am not a professional photographer but a passionate hobbyist. Thanks!

  • Jim Wells

    Hi Michael. Your right, the GN on speed lights does change with the zoom settings. First, John is talking about a single studio strobes that doesn’t zoom. Second, under the heading, “Notes on modifiers” John talks about the loss of light they produce. I’ll add that if using a modifier with speed lights the zoom should be set wide to fill the modifier.
    I don’t know your studio setup. I’ll assuming were talking about portraits. Studio portrait photographers control ALL light in the work space as John did above and shoot on a simple background or elaborate set. That means that ambient isn’t generally in play as it is with your situation. Is it possible to light your background and still achieve the 1-2 stop ratio you prefer and shoot at ISO 100? Or lower your shutter speed which will increase ambient without changes to lighting.

  • John McIntire

    Hi Michael, you’re quite welcome.

    Thank you for pointing out the zoom setting. You’re right that it comes into play when using speedlights and flashguns, but please be aware I was concentrating more on dedicated studio strobes rather than portable flashes as Jim pointed out.

    All modifiers are different. None I’ve encountered alter the output by more than a stop but as you pointed out there will be some that do. If you thoroughly test any new modifiers you get and measure and memorise the difference in output you’ll know where to and how much to compensate for your own equipment. Thanks for bringing that up.

    As far as the ambient, yes the settings I used do make it very underexposed. For a beginning tutorial, I felt it best not to involve mixing light sources so killing the ambient light with a high powered flash ensures that all of the light in the scene is controlled and created by the photographer. But if you wanted to use the calculations above combined with an ambient light source, you would meter for your background first and calculate your flash output to match those settings just like you said.

    Thanks for the feedback and I hope the article has helped in some way.

  • Yasir Mehmood

    Thank you very much for this informative tutorial, I will try to follow the instructions of this tutorial to enhance my photography skills and will also ask my fellow photographers to do the same.

    I have created many wallpapers by using the photographic skill but after this blog I am feeling improved.


  • Paul A. Bing

    Regarding turning your strobe to half power, given the inverse square law,
    shouldn’t you divide the GN by 1.4 to get the new GN?

  • Gracia Cardeal

    It couldn’t be more perfect. Can I follow you on Instagram? Thanx for sharing.

  • thanks for sharing!


  • John McIntire

    Hi Paul, you’re absolutely right. It should have said 1.4. Apologies for not catching that mistake in revision.

  • John McIntire

    Thank you Gracia. Please, follow away.

  • EXACTLY what I was looking for!

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  • John McIntire

    You’re welcome Megan. Glad it helps.


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  • Fantastic article!! Thanks for the help!!

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  • Rick Halbert

    That was awesome for simplifying the total confusion of studio strobes! It has dropped my set up times and can concentrate on the model way more! Thank you

  • Friend2303

    DPS has some great articles which have been a large part of my learning curve and this is one of the best articles for me in terms of simplifying something that intimidates me greatly. BTW how does this work for outdoor portrait. I am assuming I need to use the guide number once I determine the aperture (which would be based on background) right? Also I know you mentioned it – but would it still not be easier to use “Flash Compensation” instead of moving the strobe back and forth. Thanks much anyways – excited to try this!!

  • Marissa dela Cruz

    Thanks for sharing.
    I am confused of where i can get a guide number? How can i get that guide number in terms of what? You just mentioned an example of a guide number 66 but you didn’t say where did you get that guide number.
    Can i know or can you please tell me,us ?
    Thank you very much

  • John McIntire

    Hi Marissa,

    The guide number for your flash can be found in your manual. Here’s an example from a Bowens manual.

    Hope that helps.

  • Tim Ueltzen

    Thank you for this. If I’m using two strobes do I need to turn them down to half power or double my distance from subject?

  • John McIntire

    Hi Tim,

    Unfortunately, it’s more complicated. If your two strobes are in the same position (and of equal power), it doesn’t double the amount light. This is the inverse square law that was briefly mentioned.

    If you add a second light, you have to square both guides numbers, add them together. Your new guide number is the square root of that sum.

    So, if you start with two equal guide numbers of 64, then your formula is:


    This equation gives you a new Guide Number of 90.5

    However, if you are using strobes in different positions, for example, filling in the shadows, it’s not a problem. You just need to calculate how much of an exposure difference you want between your main light and fill and set the power accordingly.

    Say your main light you have calculated to f/11. If you want to fill in your shadows a stop lower, then you’ll position your fill light so that it measure f/8.

    I hope that helps and answers your question. If not, feel free to ask more.


  • Marco Bollaart

    Hello John, good article. But I don’ t understand why the guide number in the manual say Meters and you calculate in feet. Do I miss something ? Hope you can explain this to me. Kind regards. Marco

  • Sean Reese

    John, I have a question. I have Impact VC-500WL strobes they are reporting a guide number of 255′ (78m) @ ISO 100. I am assuming that I use the 78m and not the 255′? I don’t think I have seen a lens that can hit f/68 😀

  • Jacomina

    Hi John! Love your tutorials! I have relatively cheap but decent Visico lights. Living in South Africa and obviously working in meters. On my Visico model it states the GN as: GN (2m, ISO 100). I have two of these strobes but the number seems awfully small compared tot the number you are mentioning. Am I missing something? Please help.

  • John McIntire

    Hiya. Yes, that GN sounds a bit low. Do you have a model number for your strobe?

  • Wow John you really know how to write a blog to get some substantive comments, kudos! I enjoyed this read. Really though I would like to study deeper into this concept of using math to figure out exposures is there a reference that I can use to study this further for myself?

  • Jacques du Toit

    It works out to the same thing roughly, f/8 for 255 feet = 31.875 feet which = 9.7155m where f/8 for 78 meters = 9.75m

  • Sean Reese

    Thank you for that answer! I have since purchased new strobes but the information is still helpful!

  • Brian

    Awesome Job! Here is what I am going to be getting this coming week: Flashpoint Explor 600 (strobe), 36″ Octabox, Neewer Pro metal C Stand, and Calumet backdrop stand. So what else should I get to complete my small studio? I know I need some constant lights, but which ones? I have my EX580 II speed light if I need to use it. I’m new at studio work. Thank you for your help.

  • JR

    This is absolute sorcery! (in a good way). I had no idea of the relationship between GN, aperture and distance. Always wondered if there was any use for the GN other than “this is stronger than that”. Your article made it all practical. Can’t wait to try it! Thank you! Following you asap.

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