Tag Archive for: inverse square law

Same background, totally different results

Maximize your results with this simple technique

When you shoot for a client, delivering different options is always interesting and smart.
But different options take time, right? In this blog the same background and totally different results

Well not exactly.

Be smart with your setups.

For this example, I’m using a white background.
In the front, I’m using the Rogue black umbrella with a sleeve aimed straight at our model.
The backdrop is white seamless.

You probably already know about the inverse square law, meaning light falls off over the distance.
A great way to use this is to control your background.

I’m using the white background for my first shot in this setup.
This one was shot with one Rogue umbrella in the background and one Rogue umbrella on the front.

white background but different results You can already see a very slight light fall-off in the background, which can be solved by using a second umbrella on the other side of course as explained in the previous blog posts.

But what if you just take away the umbrella(s)

again the same white background but different result

As you can see the background now turns grey and you can add some extreme vignetting in Lightroom or Photoshop (or your favorite editor) for a completely different look.

Change the distance for total control (different results)

Using the inverse square law you can change the luminance of the background very easily.
You actually have 2 options.

  1. you can change the distance from the main light to your model.
    Move it closer to the model and the background will become darker.
    Move it further away from your model and the background will become lighter.
  2. Move your model forward to get the background darker
    Move your model towards the background and the background will become lighter.

Of course, you have to re-meter the light when you change the distance between your model and your background.

Explained wrong

I just wanted to add an extra note to this blog post.
I’ve seen several videos and articles that claim that the light halves when doubling the distance, this is however wrong.
The name already gives you the answer in fact.

The intensity of the light is inversely proportional to the square of the distance
meaning in simple turns that for every doubling you lose about 75% of your light.

In usable terms.
Place your light really close to your model and the light will fall off incredibly fast. Place it further away from your model and more of the set and model will be lit and the light fall-off will be smoother.

 

Conclusion using the same background and getting different results

When you have to shoot with certain setups always check if you can also get usable results by turning off/on certain strobes.
You might surprise yourself when you start testing this, it can be done in much more situations than you might think.

Read the post about poses and the white background 

Read more about making the background and floor totally white 

see more pictures Frank made with the Umbrella on the RogueFlash website 

check out the Digital Classroom about Umbrellas

That easy lightbulb again

Every once in a while I will take it out of the closet… my favorite light source to play with… that simple 100W light bulb in the cheapest enclosure I could find. It’s always fun to see the reaction of the attendees of the workshops when they see the possibilities they can have while shooting with a light source most would label as “unusable for some cool shots”.

 

One of the things you always have to remember when shooting with light is “distance” or in other words “the inverse square law”.
In very simple terms, if you use a light source really close to your model the light will fall off very rapidly, meaning you will get a lot of contrast in your shot, if you move the light further away the light will fall off less rapidly. So if you want to light a group it’s often wiser to move the lights a but further away, and if you want a striking high contrast portrait you can move it closer (although many other factors play a role of course, but let’s keep it simple).

With the lightbulb the power, for me, lies when you use it really close to the model and the background. The outcome is always something that surprises people and often they ask me “How many strobes did you use next to the lightbulb” 😀

 

So if you have a lightbulb in your house, don’t be afraid to use it in your next shoot, it might surprise you.

 

For much more in-depth techniques, tips etc. get my book “Mastering the Model shoot” or download one of my videos from this website.

Manon Juni 13 2015 0594

Manon Juni 13 2015 0865