You Light Up My Life Friday: Controlling The Contrast Of The Scene

Good Morning Everybody,

Whew! One more day and we are on our way to San Diego for a week.  I'll tell you, LaDawn and I are both looking forward to the break.  I've still have several projects to complete, a family portrait this evening, but that should make it “clear sailing” for next week.

A few things happening around here - I got an email from a blogger who runs a fairly large photo blog.  No names yet please.  He asked me to be a contributor to a new wedding blog he is in the process of putting together - can't tell you that name either yet.  OK, now I've got you guessing, you will have to wait till we get back from San Diego for the rest of the story - all good, so stay tuned.

Just a quick reminder, The Zumbrella Special that I've got running on the blog - 1 Zumbrella (the best shoot thru umbrella on the planet;~) together with last month's 97 minute Location, Lighting, Lenses, and Composition webinar presentation and my Shooting at the Speed of Light DVD has been extended until we return from San Diego. The entire bundle - Zumbrella and 2 1/2 hours of training is priced at only $59.95 ($123 value), at least for one more week.  Here is the link to all the info.

The new "Let My Light Shine On" webinar is quickly filling. We are covering lots of outdoor lighting techniques so it will be a great presentation packed with a ton of information. And, hey worldwide listeners, you even get a free download of the webinar too so you can listen to it any time you want.  Here is the link to register.

Hey gang, I've got a winner of a post today so how about we get on with Light Up My Life Friday.  Here we go.

Light Up My Life Friday: Controlling The Contrast Of The Scene

My little Z-Ray light, just a Brinkmann high intensity flashlight [link], is one of my favorite lighting sources to "play" with.  I love the small cone of light it throws on the subject giving me that "George Hurrell" look to my wedding portraits.  Here is a link to about 21,000 "George Hurrell" images right here - kind of a nice browse.  It gives you an idea as to what I mean by George's lighting look.

Anyway, the Brinkmann cost me about $29 on-line but others have told me they have picked one up for $19 at Wal-Mart - what a deal.  I think any bright flashlight would work, I just like the Brinkmann.

Figure 1.

Here is the deal though.  Some people have commented that they tend to over expose the highlights with the Brinkmann.  That means that they are getting too much contrast in the scene when shooting with the Brinkmann light. That got me thinking - what's happening?.  How can we control the contrast of the scene when using continuous light sources, or any light sources for that matter when making our shots? Well, it’s a pretty simple fix.

Hit the "Read More..." link below for the rest of the story.

Remember, the Brinkmann is a continuous output light source.  The Inverse Square Law  tells us that the the brightness of the light on the subject is inversely related to the distance that the light source is to the subject. 

OK, what am I talking about ?  At ten feet away, the Brinkmann will give me an exposure of F4 at 1/6 second at ISO 800.  Check out the first image in Figure 1 - those were the settings for image above.  Notice how dark the shadows are in the shot.  That's because the ambient light was not bright enough to fill the shadows much.  No problem, in my opinion – I find it still to be an exciting shot.

Now look at the image below - Figure 2 – which I posted two days ago entitled, "Cityscape". It was taken at F5.6 @ 1/8 at ISO 1600.  It too has little detail in the shadows - again not much light to fill the shadows  because of the late night shoot.  In both of these images, my assistant was holding my Z-Ray about 10 feet from the subject.

Figure 2.

Now let's take a look at the last image. It's exposure was made at F5.6 @1/10 second at ISO 800. My Z-Ray was only about 5-6 feet away from the subject, hence the substantially increased exposure on this shot. 

In fact if you do the calculations - F5.6 allows half the light to the sensor as F4.0.  That coupled the fact that the shutter speed was 1/10 second in this third image instead of 1/6 second, as shown in the first image, means that the third image was made with my Z-Ray 4x brighter than it was when making the first image. Why? Because it was closer.

That follows the Inverse Square Law exactly - halving the distance of the light source to the subject increases the brightness of the light 4x.  Or said another way, doubling the distance of the light source to the subject reduces the light brightness to 1/4 its original brightness.

In our third image - Figure 3 - though, notice the shadows have some detail in them.  The reason for this is because the ambient light at the hotel where the image were created was quite a bit brighter than the ambient light in the late night outdoor shoots.

Figure 3.

So you ask, "Can the contrast - the brightness of the highlights to the shadows - be reduced any more? Can I get even more detail into the shadow areas of the shot?"  The answer can be made in two ways.  The first would be to increase the amount of ambient light in the scene.  That may not be an easy solution in a hotel if all the lights are at full brightness already.

So what is the next possibility? Folks, this next sentence will change your lives;~).  Here we go.

Back up the Z-Ray to 10 feet away!  What happens? Well, now with the Z-Ray light intensity reduced on the subject by - how much? Remember the Inverse Square Law - the intensity of the light would be decreased to 1/4 it's original intensity.  That would necessitate an increase in exposure to say F4.0 at 1/5 second to get the proper exposure on the bride - better grab the tripod.  Check out Figure 4 below.

Figure 4.

Since the ambient light doesn't change at all, the increased exposure would do two things:

1. Bring a lot more detail into the shadow areas of the scene.

2. Reduce the contrast of the portrait because the shadow areas are much brighter now and closer to the brightness of the highlights.  Check out the Figure 4 to see an example of this effect.

Z-Note:  I used Lightroom to give me the image you see in the forth example.  I'm not cheating,  I'm "dramatizing" the effect of the exposure change.  Still you get the idea.

So the bottom line is this.  If you are over-exposing the highlights and getting a way too contrasty look in your images when using your Z-Ray (or any other light source for that matter), simply increase it's distance to the subject (or reduce it's output). 

If you want a more dramatic result - read that as a more contrasty image, then move your light source closer to the subject.  The ambient light will remain the same, but the highlights will now need a faster exposure so as to not be over-exposed but the shadows will now go much darker thus increasing the contrast of the scene. 

The bottom line is this - just use the working distance along with your exposure adjustments to control the contrast of the image when using any continuous light source to illuminate the subject.

Hey gang, I hope that gave you a pretty good idea on how you can control the contrast of the scene with a continuous light source or any light source for that matter.  Remember, it's always about the ratio of the main light source with the ambient that controls your contrast in these situations.  Hope this explanation has helped.

Hey gang, that's it for today. We got bags to pack, planes to catch, and places to go.  See ya' next week in beautiful San Diego! You know, I hear the pixels are even happier in San Diego because of that famed great weather they have along the beaches - can't wait.  Adios everybody, -David