Good Catch!

Catch light, that is. The life of the portrait.

catchlight.jpg

They say it is all in the eyes. And in portraits the eyes come alive with the presence of a catch light. But before we talk specifically about catch lights, a refresher on reflections. After all, we don’t photograph people, places, or things. We photograph the light that reflects off of those people, places, and things. There are two basic types of reflections. Diffuse reflections define the subject and its texture. We base our exposure on the diffuse reflections, whether that be skin, a tree, a flower, etc. Specular reflections are direct reflections of the light source, like a mirror. We also have shadows, which are areas that don’t get lit.

As you change the distance between your light and your subject the diffuse reflections get brighter or darker. Move them closer together and you have to lower your exposure to maintain the correct exposure. Move them farther apart and you need to provide more exposure. Pretty simple and intuitive. The diffuse reflections loosely follow the Inverse Square Law of physics. I am going to skip the math and science part here, but basically it tells us that changing the distance between the light and the subject will have a bigger effect on the exposure than you might expect. Light falls off rapidly as you move the light farther away.

Then we have the mirror-like specular reflections. Specular reflections are the same brightness as the light source, no matter the distance. You can easily see this by pointing a flashlight (torch) at a mirror and observing the brightness as you move the light closer or farther away. At this point you might start to ask why these highlights don’t follow Inverse Square. The answer is that they do! But in a different way. As you move the light source farther away from your subject the specular reflections get smaller, as you move the light closer the specular reflections get bigger.

Once you have an understanding of this you can start to consciously control the relationship between the various highlights. And that is where we come to discussing the catchlights in the eyes of our subjects. This stems from a question I recently received, “Can I make the catchlights less noticeable by moving the light farther away from my subject?” And the answer is, No. Moving the light farther away will make the catchlights MORE noticeable. They will be smaller, yes, but they will also be brighter in comparison to the diffuse reflections. The followup question was if dimming the light would reduce the brightness of the catchlight. Again, the answer is no. Dimming the light lower both the diffuse and specular reflections and you will need to increase the exposure, leading to the same relationship between them.

Let’s look at what is happening. Start with a light in a softbox at about 36-inches from our subject. We meter the light and find that the proper exposure is at f/8. Now move the light back to 48-inches from the subject. To maintain the same f/8 exposure we have to raise the power of the flash up about 1 stop. Now the face is still at the same exposure level (moving the light back and raising the power level compensated for each other). But the light is 1 stop (2X) brighter and because the catchlight is a mirror reflection, it is now twice as bright than it was before, making it much brighter than the diffuse reflection.

We can also look at this going in the opposite direction, bringing the light in closer to our subject. If we bring our light in 3 times closer, say it was originally at 9 feet away and now we move it in to 3 feet away, what happens? We have to stop down (change aperture or lower the flash power) by 3 stops to maintain the proper exposure. That makes the specular highlights 9 times darker than they were. Let’s see that that looks like in pictures.

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In the top image the lights are set 36-inches away from the subject. In the lower image the lights have been moved back to 48-inches from the subject. In doing so I had to increase the flash power by one stop to maintain the correct exposure on the “skin.” This in turn made the catchlights one stop brighter in the lower image. So even though the catchlights are smaller in the lower image, they are brighter in comparison to the rest of the face.

For this next example I attached a small mirror to the mannequin’s forehead and made two photos lit with a 2x3 softbox being reflected directly back to the camera. The one on the left had the light 9 feet away from the subject. The one on the right had the light 3 feet away. You can see how bright the softbox reflection is on the left, causing a lot of lens flare and haze, compared to on the right. The exposure on the face, though remains approximately the same. The reflection in the mirror on the right is 9x less bright by bringing the light in to 1/3 the distance. You can also see the difference in the highlight on the tip of the nose, small and bright when the light is far away, larger and more translucent when the light is in closer. The catchlight in the eyes on the right gives away one of my little signatures, the black bars of tape across the front of the softbox to simulate a multi-plane window.

mirrors.jpg

Let’s look at a different example, this time a still life/product photo. This shiny can was lit with one 60-inch octabank. On the left the light is about 48-inches (120cm) away from the can. On the right the light was moved in to 12-inches (30cm) away. There are a few things to observe here. On the left there is a strong highlight that you can see in the red cap and behind the text on the label. While you can read the label text, it is a bit washed out by the highlight. On the right, with the light in closer, the highlight looks much nicer on the red cap and the text on the label is much easier to read. You might also note that on the right the overall look of the text and the can is lower in contrast and color saturation. That is one of the downsides of using a large soft light in close. A set of soft grids on the octa might have helped bring back the contrast, but at the cost of seeing the grids in the highlights. Below is another series of photographs of this can. This time lit with a 2x3 softbox. On the left the light is 48-inches from the can and we see the bright highlight making the text hard to read. In the middle the softbox is set 12 inches from the can and the text is more readable. Over on the right I added a soft grid to the softbox. I think I see a bit more contrast and saturation, but you can see the cells of the grid in the highlight, especially in the red cap and at the shoulder of the can (see my post about grids for more info).

can-reflections.jpg

And now for the controversial question about what shape catchlights are preferred. My preference is for rectangular catchlights. That is the shape you get inside from a window, a doorway, or a skylight. It is also what you get from a wide open sky outdoors. So many people talk about, and advertisements for lighting modifiers mention, “natural” round catchlights. I have to assume they are referring to the shape of the sun. But when we photograph people out in the sun we don’t usually get a round catchlight as they are either squinting, or turning away from the sun. Sure, in many animal photos we see small round dot catchlights, but rarely with people. And they remind me of department store family portraits from the 1960s. It comes down to personal taste. It is a rare client who comments on or requests a specific shape to the catchlights in their eyes. Dare I bring up the topic of pupil size? Maybe next time.

round catch lights

Until then, if you have any questions about this or any other lighting questions please comment below or join my studio lighting group on Facebook.

Thanks!
John

Light as a Feather

Feathering the light is using the shadow edge of your light to control your shadows.

Most beginning photographers seem to start out in the studio with their light pointed directly at their subject. And this works in many situations. You can keep doing that and all will be well. But if you want to take things up a notch and gain more control over the light on your scene you will need to learn how to position the light to control its coverage. And that’s what we are here for today. Control the stamp of light on your subject be feathering the light.

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The first thing to learn about feathering your light is that it does NOT make your light softer. We know that the larger the light source as seen by the subject the softer the light. What happens when you feather the light? Take a look at the images on the right where we are looking over the model’s shoulder at the light. On the top the light is pointing directly at the subject. On the bottom the light has been pivoted towards the camera to point more across the face of the subject. In doing so the light has become narrower, which is smaller. If you think back to the post about shadows you will see this is more like a strip light where the shadow edge quality will be the same up and down (the long dimension of the softbox is still the same size), but the shadows from right to left across the face (the nose shadow) will be harder because the width of the light is narrower.

The light across the face is slightly harder, but it is more even. The coverage is wider. But it isn’t any softer.

We can also feather the light away from the camera, towards the background. This will make the light across the face narrower and harder with deeper shadows. It is more akin to a split light when you do this. Let’s look at examples.

Feathering the light using a hard light source (an 11-inch deep zoom reflector)

Here I am using a hard light source to emphasize the shadow edges. On the left the light is pointed directly at the subject. In the middle the light has been pivoted towards the camera to cover a wider area of the face, opening up some of the shadows while at the same time making the shadow edge harder and more defined. Over on the right side I pivoted the light towards the background for another look that is even more shadowed and contrasty. Again notice that the nose shadow to the side has become very hard edged due to the light becoming much narrower.

Feathering becomes an even more powerful tool when working with multiple subjects in the photo. Here I have two subjects and a hard light.

Again, with the light pointed directly at the pair there is a strong falloff in light from left to right with deep shadows on both faces. By pivoting the light towards the camera the light evens out between the two faces as seen in the middle. Pivoting towards the background makes the difference in exposure between the subjects even farther apart.

Now let’s look at it with a softer light, this time a 2x3-foot softbox.

feathering.jpg

This time I changed the order and you will see why in a moment. I started out the same with the softbox pointed directly at the subjects. Turning it towards the background exacerbated the problem of uneven exposure on the two subjects. Feathering the light towards the camera for the third image evened out the exposure. And in the bonus image I turned the light even more towards the camera and you can see that this lit up the subject farther from the light more than the subject closer to the light.

Here is a diagram to help explain.

There is your control via feathering.

Cheers!
John


A Little Help From My Friends?

I have something that I am stumped on. I’ve had a couple of friends tell me they shoot this way and I have seen some “big name” photographers that I have a lot of respect for talk about this. This refers to taking two photos with a slightly longer lens and stitching them together instead of one photo from the same position with a shorter lens.

I am not referring to the “Brenizer Method” of taking a series of photos on location with a long lens and stitching those together to make it look like a wide angle photo with limited depth of field. You can see that in this article from FStoppers. The photos I am referring to are usually made in a studio situation with a plain seamless backdrop.

They talk about the difference in “compression” between the shorter and longer lens. Something about one of these (the longer lens images stitched together) having more impact and intimacy. And this is where I get lost. The “compression” effect comes from the distance between the camera and the subject. All lenses have the same perspective from the same camera position. They just magnify more (longer lens) or magnify less (the shorter lens). If you take the image with each lens without moving the camera and crop them the same the scene will look the same. The perspective is the same in the area of the images that are common to each other. The only difference I can imagine is that when you pan the longer lens side to side for the two photos the camera is at a slightly different angle, but not enough to be all that noticeable.

The top image was made at 70mm with the camera horizontal. The lower images were made at 106mm with the camera vertical.

The top image was made at 70mm with the camera horizontal. The lower images were made at 106mm with the camera vertical.

I’ve tried it myself and don’t see any super noticeable differences between the images to make the process of photographing the scene (usually a portrait) twice and then aligning layers in Photoshop. Here are some images where I tried this.

My camera was firmly locked down on a tripod and I made the first image at 70mm with the camera horizontal. Then, without changing the distance I changed the focal length to 106mm and rotated the camera on axis to vertical and took the next two photos, panning the camera a little bit left and right to capture the width of the single 70mm capture.

I then brought the images into Photoshop. There I had the two 106mm images in one document on two layers. I used Auto Align Layers to merge them together into one wider image, then flattened the image.

Next I brought the 70mm image into the same Photoshop document on its own layer and again used Auto-align layers to size them the same. And here are the two results…


Single capture at 70mm

Single capture at 70mm

Two captures at 106mm stitched to create one composite image.

Two captures at 106mm stitched to create one composite image.

Here are the two photos in a slider. On the left is the photo made with the shorter lens. On the right is the photo created by stitching together the two image from the longer lens. The only difference I see is at the bottom of the image and I think that has something to do with the centering of the lens and the act of rotating the camera from horizontal to vertical. I see no difference in the face of the subject.

 
 

Those of you who use this technique, what am I leaving out or doing wrong? Can you send me a set of images where one was made with the shorter lens and the other is made from longer lens images stitched together where you can clearly see the difference?

Thanks!
John

Watt-What??

What are all those numbers?

“The tremendous number of speedlights in all shapes, sizes and prices exhibited at recent photo shows leaves even the electronic flash engineer confused. With all the claims, counter-claims and partial information. It is no wonder that the dealer is wary. On top of that, think of the poor customer. Confronted with the array of claims, and with no basis for comparison, it is amazing that so many have the courage to buy. What is more sorely needed are a few simple facts that can be used asa a basis of comparison. “

Though it sounds current, the above is a quote from an article by Harry L. Parker, president of the American Speedlight Corp. (ASCOR) in Photographic Trade News, May 1953. And it holds true today.

Let’s look at just one term, watt-seconds. What does that refer to? Is it related to watts that we commonly use to talk about continuous light? Does it tell us how much light a flash unit produces? Here are some quotes from publications by ASCOR, Norman, and Paul C. Bufff:

ASCOR (1950s): “MASS CONFUSION — For too long most people have rated speedlights (not the same thing as what we refer to as speed lights today, these were units that weighed hundreds of pounds and stored thousands of watt-seconds of energy in their capacitors: ED) in watt-seconds. Just what is a watt-second? If you really know, you are one of the unusual photographers. Then again, what photographer really cares? Watt-seconds is not a rating of light output or speedlight equipment. The use of watt-seconds, microfarads, and other terms has so confused the photographer that many are thoroughly baffled about electronic flash.”

Norman (1970s): “HOW MUCH LIGHT — For many years the common term used to describe the output of an electronic flash unit has been watt seconds. Unfortunately this is very misleading in that the term ‘watt seconds’ is used to describe the amount of energy store in the main discharge capacitors and is not directly related to the amount of actual light output.” (You can download a set of Norman flash guide pamphlets here.)

Paul C. Buff (1990s): Wattseconds defines the amount of electrical power supplied to the flashtube(s); not the light energy which the tubes emit. There are several design factors that affect how efficiently the flashtube converts electrical energy into useable light. These same factors also affect the flash duration. The same parameters which tend to decrease system efficiency also work to shorten flash duration, potentially to the point of inviting reciprocity-induced color errors…” (More on the Paul Buff site.) This was obviously written in the film days, whereas with digital we don’t have to worry about reciprocity departure and people are clamoring for short flash durations so they can splash milk on their subjects.

So, how do you compare the output from one flash/strobe to another? You pretty much cannot do it from the specs. You need to have both flashes in hand with the same modifier on each and do your own A/B comparisons. Luckily with digital we aren’t as beholden to super powerful flashes like we were in the film days working with 8x10 cameras at f/64 with a bellows factor added in requiring multiple pops from a 2400 ws box for a still life setup. For portrait photographers 200 ws would be my starting suggestion, and around 500 ws at the top end—and make sure that the strobe has the ability to dial down. I find more situations where I want less power from my strobes than more.

And everyone makes it difficult to tell just how much power you are using. There is a very popular line of flashes that use more speed light-like power descriptions: full, 1/2, 1/4, 1/8, 1/16, etc. This would be all well and good if all of their flashes had the same power. But what happens if you want to compare different models of their flashes on the same set? Flash A is 600ws, so 1/4 power is 150ws. Flash B is 320ws, to 1/4 power on that unit is only 80ws. Very frustrating if someone is trying to describe their lighting to you and says one light was at 1/32 power and the other was at 1/8 power. If the two lights aren’t the same, they could be putting out the same power as each other. Or the 1/8 power flash could be brighter than the 1/32 power flash. You have no way of knowing unless you know exactly which model(s) of flash units that person is using in which position.

Theoretically the number system of power levels should help compare output. As I understand it, when originally proposed it was to be based on a particular reflector and distance that could be replicated between brands. Say, for example a company had flashes ranging from 900ws to 3600ws with the same reflector and distance 10 would be the highest level (3600ws). Their 1800ws unit would only go to power level 9 (1 stop less), and there 900ws unit would top out at power level 8. Then another manufacturer would test their lights with a similar modifier/reflector at the same distance and even if the WS rating was different, say 600ws, if it put out the same amount of light as the original’s 900ws unit its top setting would be 8. Then you would know that any light that went to power level 10 had the same output. Any light set to 9.3 would be the same, etc., etc. However, in practice this has not caught on. Most flashes seem to just use 10 as their top level, no matter the actual output.

Oh, well… Pick a brand of lights (my choice is Interfit*) and enjoy them. Don’t compare them to others. Make the best photos you can. Light is light. Put your energy into the creative side.

*Yes, this is an affiliate link. If you purchase via this link or use the code “cornicello10” at checkout from Interfit you will get a 10% discount on your order (and free shipping on orders over $100) and I will get credit and may be compensated for directing you to them.

Cheers!
John

Breaking the law

Can grids help you break the law?

If you are using soft grids on a softbox in very close to your subject you might be breaking the law. The Inverse Square Law, that is.

inverse-square.jpg

Just about everyone learning how to work with light learns about the Inverse Square Law early on. “The intensity of light falling on a flat surface at right angles to a point source of light is inversely proportional to the square of the distance.” If you double the distance between the light and the subject you get 1/4 the amount of light on the subject. Triple the distance and you get 1/9 the light on the subject.

In practice it isn’t so cut and dried. The law applies to a point source of light—we rarely encounter that in our photography. Simplifying it down, it says that as you increase the distance between a light source and a subject the light spreads out and appears to fall off in intensity very quickly. There isn’t less light, but the light is covering a wider area, so fewer photons are reaching the subject with the balance of them zooming on by past the subject and not contributing to the illumination.

Here you can see me using a light meter to measure the output from a 2x3-foot softbox in close and a bit farther away. Without the grid the light falls off as expected, going from f/6.3 in close to f/5.0 backed away. But when the grid is in place the meter reads the same f/5.0 at both distances. Have I broken the law.

metering-1.jpg
metering-2.jpg

What is going on is that in close the meter sees a small number of very bright grid cells. As you back up a bit, but still in close, the meter sees a greater number of cells, but they are less bright. And this averages out to give the same exposure reading at the different distances. This just happens in close. Once you back away to a point where the meter can see the entire softbox things go back to normal and light falls off as expected.

Let’s take a step back to look at what grids do. Grids are the opposite of diffusion. Grids are baffles that control the spread of light. They increase contrast by blocking the light from hitting walls, floors, ceilings, or anything else in the environment that would become a secondary light source reflecting light into the scene to open up the shadows. They also help control the spill of light onto the backdrop.

So, how does this affect photographs? Normally, without the soft grid, as you move your light in closer to your subject the light gets larger as seen by the subject. We say it gets very soft because it fills in its own shadows and causes the shadow edge transition to spread out. It also leads to a loss in color saturation. With the grid, as you move the light closer to the subject the grid cells occludes light from the edges of the softbox so once the light gets close enough for that to happen it appears smaller as seen by the subject. Then as you move it in even closer its size appears to stay the same and the contrast and saturation remain the same.

You can use the slider on the right to compare the scene with and without the grid to see the change in contrast along with the slight change in color saturation. Both images are lit with a 2x3 softbox positioned 12 inches away from the tip of the mannequin’s nose and both were metered at f/9.0. Although at the same distance, the scene lit with the grids has a harder light quality because the grids made the light appear to be smaller. If the softbox was moved back to a distance where the subject sees the entire box the differences go away.

The grid on the softbox is seen in the catchlight in the eye.

The grid on the softbox is seen in the catchlight in the eye.

The downside of soft grids is that they show up in reflections. That could be in the catchlight in the eyes of a portrait subject, as you can see here, or in shiny objects in a still life photograph.

Don’t be tempted to put some diffusion over the grid, though, to try to hide the pattern. The diffusion will completely counteract the effect of the grid.

Thanks again for following along! Send me your studio lighting questions. Or take a look at my updated book, Anatomy of a Studio Portrait.

Cheers!
John

What does that modifier look like?

I had a few spare minutes yesterday (New Year’s Eve), so invited a friend and her daughter over to make some photographs with a variety of light modifiers. Here are the results of the 28 configurations we tested.

All photos lit with an Interfit Photographic Honey Badger strobe head. All photos metered to f/6.3. Subject seated about 2 feet in front of white seamless paper. All lit with the single light with no reflectors or fill light. Camera was set to “daylight” white balance (yes there is that big a difference in skin tone between them) and the only post-processing on the images was to crop them to a square.

Here is the list of modifiers used and some notes:

  • Interfit 48-inch deep parabolic softbox with both diffusers in place

  • Interfit 48-inch deep parabolic softbox with only the inner diffuser

  • Interfit 48-inch deep parabolic softbox with no diffusers (open face)

  • Interfit 48-inch deep parabolic softbox with 20-inch black foam-core disk blocking the middle of the light (looks like a ring light)*

  • Neewer 36-inch parabolic softbox with CheetahStand focusing rod with the flash head pulled all the way in to the softbox

  • Neewer 36-inch parabolic softbox with CheetahStand focusing rod with the flash extended to the opening of the softbox

  • Neewer 36-inch parabolic softbox with CheetahStand focusing rod with the flash extended to the opening of the softbox and a 20-inch black foamcore disk blocking out the middle of the light*

  • SPSystems 28-inch folding octabox with both diffusers in place Light boomed over camera on axis with lens

  • SPSystems 28-inch folding octabox with only the inner diffuser

  • 22-inch Speedotron beauty dish centered over the camera with diffusion sock

  • 22-inch Speedotron beauty dish without the sock

  • 20-inch metal dish reflector centered over the camera

  • 20-inch metal dish reflector with a diffusion sock on it

  • Interfit Deep Zoom reflector at camera left

  • Interfit Deep Zoom reflector with its diffusion sock

  • Interfit Deep Zoom reflector with 10-degree grid

  • Interfit Deep Zoom reflector with 10-degree grid and diffuser to show that the diffuser negates the effect of the grid

  • 7-inch metal dish reflector

  • 7-inch metal dish reflector with one sheet of #261 diffusion

  • 7-inch metal dish reflector with two sheets of #261 diffusion

  • 7-inch metal dish reflector with 10-degree grid

  • Interfit 2x3-foot softbox pointed directly at the subjects

  • Interfit 2x3-foot softbox feathered in front of the subjects

  • Interfit 2x2-foot collapsible softbox (which comes with the Honey Badger and has a recessed front panel)

  • 2x2 softbox with a flat front (old and apparently yellowed with age)

  • Interfit 65-inch** Silver Parabolic umbrella with the head pushed almost all the way into the umbrella

  • Interfit 65-inch** Silver Parabolic umbrella with the head pushed in (focused) and a 20-inch black foam-core disk blocking the center of the light

  • Interfit 65-inch** Silver Parabolic umbrella with the head mounted on a separate light stand about 5-feet in front of the umbrella

    * see the photo below
    **measured across the opening, other companies call this a 7-foot or an 84-inch as they measure around the back arc of the umbrella

The black foam-core disk was used in an attempt to make the lights act something like a defocused Broncolor Para. The sliding focusing arm in the 36-inch para was for the same reason. But looking at the photos, I think that I like the big 48-inch Interfit Parabolic Softbox in any of its configurations (2 diffusers, inner diffuser, no diffuser).

Some photos for clarification

Strobe head mounted on a separate stand 5 feet in front of the Interfit 65-inch Silver Parabolic Umbrella

Strobe head mounted on a separate stand 5 feet in front of the Interfit 65-inch Silver Parabolic Umbrella

Black foam-core disk blocking the center of the deep parabolic softbox

Black foam-core disk blocking the center of the deep parabolic softbox

Cheetah “Chopstick” lets you position the flash head inside the softbox, sliding it closer to or farther from the back of the softbox to focus the light

Cheetah “Chopstick” lets you position the flash head inside the softbox, sliding it closer to or farther from the back of the softbox to focus the light

What information lurks in the shadows?

Only the Shadow knows.

And he has something to say! Shadows are a very important piece of our photographs. Shadows help define our subject. They help set the mood of the photograph. They can hide things we don’t want to show. They can tell a story about how a scene was lit. And that’s what I am talking about today. What can we see in the shadows?

Here are my descriptions for the 14 images on the right (click on the image for a larger version):

  1. Standard 7-inch metal dish reflector
    Notice slight double-edge to the shadow due to the flash tube being slightly brighter than the surrounding reflector.

  2. Standard 7-inch metal dish reflector with one layer of diffusion material
    Contrast is lower from light bouncing around the room, shadow edge is more homogenized by the diffuser. The shadow edge is the same, no extra softening from the diffusion, just a brighter shadow.

  3. Standard 7-inch metal dish reflector with two layers of diffusion material
    Very similar to #2 but needing more flash power. Extra diffusion did warm up the color. Still has the same edge with no additional softening.

  4. Standard 7-inch metal dish reflector with 10-degree grid
    Narrow beam of light doesn’t hit walls, ceilings, etc. (environment), so more contrast. Still has the same shadow edge quality, just a darker shadow and restricted coverage on the background.

  5. Standard 7-inch metal dish reflector with 10-degree grid plus a layer of diffusion
    Brings us back to what we had in #1 or #2, but required 5 more stops of light power to maintain the same exposure. Don’t put diffusion in front of a grid! It negates the effect of the grid at the cost of a lot of your flash power.

  6. Deep Zoom 11-inch reflector
    Narrower light been from the deep reflector gives a darker shadow, somewhat similar to the grid in #4, but like #1 the shadow edge is doubled because of the difference in efficiency between the light direct from the flash tube and the light bounced off the walls of the reflector. Diffusion would help homogenize the shadow, but will also take away some of the contrast.

  7. Deep Zoom 11-inch reflector with 10-degree grid
    Even less environmental bounce producing a darker shadow.

  8. 1x3 strip box in vertical position
    Narrow modifier produces little shadow along its long dimension (up/down here) with much more shadow along its shorter dimension (left/right here).

  9. 1x3 strip box in horizontal position
    Rotating the narrow box moves the shadows. The left/right shadows are a little bit tighter while we now have up/down shadows. This is especially noticeable on the light stand holding the silhouette. In #8 it casts a wide shadow, while in #9 the wide pattern wraps around the narrow object and there is virtually no shadow.

  10. 2x2-foot square softbox in close at 3-feet
    This softbox has both an inner and outer diffusion panel. Shadow transition is soft

  11. 2x2-foot square softbox backed up to 6 feet
    The box gets smaller in relation to the subject when moved back.The shadow gets a harder and more defined edge. The background brightens up slightly (depth of light, inverse square law). More light bounces around the room picking up some warmth from the wooden floor.

  12. 2x2-foot square softbox at 6 feet with an extra layer of diffusion
    Shadow quality remains the same, but image picked up some warmth from either the wood floor bouncing in or from the diffusion material (or both). Requires more flash power.

  13. 46-inch Photek Softlighter umbrella WITHOUT the diffuser
    Large, round light. Even shadows all around. Background is brighter than #14 due to longer light path and depth. Although the umbrella is 36 inches from the subject, the light path is from the flash to the umbrella (24-inches) and from the umbrella to the wall (36-inches) so the distance of light is like having a forward facing light at 5-feet away instead of 3-feet, as you would get with the front diffuser (see #14).

  14. 46-inch Photek Softlighter umbrella with the diffuser
    Adding the diffusion cover has a slight effect on lightening the shadow density. Background is slightly darker as the light source (the diffusion panel) is closer to the subject. The closer the light is to your subject, the darker the background will be.

All the photos were metered to give the same exposure. In most cases the aperture remained the same (f/4.0) and the flash power was adjusted to maintain correct exposure. The exceptions are the exxamples with the Deep Zoom reflector, as it was very efficient and I could not lower the flash power enough so I had to stop down the lens to f/7.1. 

The main take-aways from this lesson is that the shape of your modifier determines the shape of the shadows and the size of the light as seen by the subject determines the size of the shadow width or the quality of light, that is hard or soft. Diffusion, along with the environment, controls the shadow density or contrast. Adding diffusion directly to a light, where it doesn’t make the light any larger, does not soften the light. It is a very subtle, but important concept. Diffusion does homogenize the light, making it more even across its field. And, depending on the environment, fills in the shadows making them less dark by bouncing off the walls, floor, ceiling, and other surroundings. Don’t confuse contrast with quality.

As I said, the difference can be subtle. Here we have three photos to compare. The first (A) was lit with a standard 7-inch diameter silver metal dish reflector. It casts a hard edged deep shadow. Next, I taped a sheet of diffusion material over the reflector (B) and you can see that the edge shape and transition (quality) has remained the same. What changed was the depth or darkness of the shadow (contrast). The diffusion spread the light around the studio and made the shadows lighter in tone, but the edge didn’t change because the light size didn’t change. For the third photo (C) I switched to a 20-inch diameter light modifier without diffusion and you can see here that the edge got softer and the transition got wider as the light was able to “wrap” around the subject for a softer light quality.

contrast-vs-quality.jpg

Now let’s look at what happens when we keep the same small 7-inch diameter reflector but add single and double diffusion. The first sheet of diffusion material makes the shadow brighter and also homogenizes the shadow edge so there is no longer a double-shadow (from the flash tube and the reflector not being equal in brightness). Adding the second layer of diffusion slightly lightens the shadow, but not appreciably. It does not in any way soften the light.

multi-diffusion.jpg
triple-diffusion

I can anticipate a comment and question. That’s all well and good for diffusing a small light. I am using a Photek Softlighter and want to double (or triple) the diffusion on that. What happens there? Let’s take a look! Here are four examples starting with the Softlighter umbrella on its own without the diffuser. Next is with the diffuser. Then for double diffusion I hung a roll of diffusion material in front of the Softlighter to double-diffuse it. Then I doubled that up to make it triple-diffused (see the photo on the right). Adding the diffusion panel to the bare umbrella actually limits the spread of the light and makes the shadow a bit darker. Adding additional layers of diffusion on top of that brighten the shadows ever so slightly and start to add some warmth to the color. But again, no change in the quality/softness of the light from extra diffusion. The size of the light remained the same.

This environmental bounce can also cause color casts if the room isn’t neutral in color. In a larger studio, or in a studio with black walls, ceiling, and floors, or in an open field the changes in contrast on the subject with or without diffusion and grids will be much less noticeable.

 

 

Well, this brings us to the close of another year. 2018 has been quite a year for me. The biggest event was the passing of my 98-year-old mom, Rose, in August. Thanks for everything you have done for me and for all the support for my taking my own direction in life. I could not have had a better mom. Rest in peace.

So, here is looking to a bright new year with new challenges and accomplishments. I wish you all a Happy New Year! Stay safe and be well.

Cheers!
John














When your big light just ain't so big

Lighting a group

We all know that a large light in close to the subject is a soft light. As we move the light back away from the subject a couple of things happen. First, the light gets deeper. Second, the light gets smaller.

Deeper
When you move your light back the light rays are more parallel and fall-off in intensity slower. At one extreme we have sunlight. The sun is so far away that light rays reaching the earth are almost parallel. The same amount of light reaches you where you are standing as reaches someone else a block or two away from you (or miles away). So we know that if we have to light a group of people with a number of rows we need to move the light back so a similar amount of light reaches the back row as reaches the front row. If the light(s) is too close in the fall off will be rapid and the back row will be dark or the front row will be overexposed.

Smaller
Smaller light equals more defined shadows. A small light cannot “wrap” around the subject to cause a wide shadow edge.

Diminishing Returns

(click to enlarge)

I feel that after a certain distance the size of the light doesn't really matter all that much. A 60-inch umbrella far away is just as hard as a smaller modifier. So, I gathered up the studio staff for a group photo and lit it three ways.

Have you met the staff? An interesting bunch. Over on the left we have our lobotomy patient, next is our exhibitionist, then the lowly photographer, and finally that guy who is just a shadow of his former self. Look for a new post about shadows coming soon to this blog.

The light was set up 9-feet away from the group and flash power was adjusted to give f/7.1 in each photo. The first photo is with the 60-inch umbrella. The second photo is with the 7-inch dish. The third photo is the same 7-inch, but with a sheet of diffusion material taped to the front of the reflector.
Looking at the three photos, the big difference between them is in the shadow density. As I expected, the 60-inch has the lightest tone shadows, followed by the diffused reflector. They each allowed more light to bounce around the room to open up the shadows.
But what about the light on the faces? Surely the big umbrella is going to be the clear winner here. Or is it? I see very little difference in the light on the faces in these three photos. It just took a lot more flash power to light with the umbrella than with the smaller, more efficient reflector. And that can be a big consideration if you are going out on location to make the group photo, especially if using battery-powered flashes. However, the umbrella or the dish with diffuser will cast a wider area of light that you might need for a very large group if you want to stay with a single light source.
Of course, if this was to be a portrait of one or two people, I could have the big light in much closer and could be more creative with lighting patterns, and separating the subject from the background, and on and on, etc., etc. But for groups you need to pull the lights back. And, in doing so, you might find that you don't need as large a light or as much strobe power as you thought you would.

 

 

BONUS MATERIAL

Many aspects of photography are related and many of them deal with distances. Here are some ways you can apply knowledge about one aspect of photography to learning another. First we have depth of field and depth of light. As you move your camera back away from your subject your depth of field (the area of the scene that appears reasonably sharp) gets larger. Taking that to lighting, as you move your light back away from your subject your depth of light gets larger. The closer the light is to your subject, the darker the background will be. The closer your camera/lens/aperture combination is to your subject, the more shallow the depth of field.

Next is perspective. The closer your camera is to your subject, the smaller the background will appear. Conversely, as you move back away from your subject the background gets larger. This is often mis-labled as telephoto compression, but it is the physical act of moving back that causes the change. You just tend to use a longer lens when farther back to magnify the subject to fill the frame, which makes people blame the lens.

Very much related to this is how a face looks in a photograph. The closer your camera is to your subject the more pronounced their features will appear. As you move back away from your subject their features flatten out. In close your subject’s nose looks bigger in relation to their eyes and ears. But as you move back the features flatten out as the nose, eyes, and ears get relatively closer to each other than to the camera. When you move back you can switch to a longer focal length lens again to fill the frame, but like before it is the physical moving back that changes the depth of features of the face. As in the lighting situation above, there is a point of diminishing return. Once you are in the range of 12-15 feet away from your subject I don’t think that moving any farther back will have any more effect.

How do you like to light large groups of people?

How do you apply what you know about one aspect of photography to other aspects?

Thanks again for following along!
John