Umbrellas andSoftboxes and Dishes, oh my!

Choosing the lighting modifier to use for portraits

You have probably grown as tired of looking at me as I have. So this morning I hired my friend, Ny, to come over to help with more comparisons of light modifiers. For this series I used an Interfit S1 battery powered studio light and a variety of modifiers in different shapes and sizes. I photographed Ny with each modifier and with and without a white fill card on the shadow side of her face. The camera (Canon EOS 6D) was set to the Daylight color balance preset. You can see that some of the modifiers are very different in color temperature than others. The flash power output was adjusted for each modifier to give the same f/5.6 meter reading. Ny was seated about 4-feet in front of a white seamless paper backdrop. The lens was the Canon 85mm f.1.8 set to f/5.6 and ISO 100.

And without further ado, here are the test results.

Comparing the look of the 46-inch Photek Softlighter II with no diffusion (umbrella only), with a single diffusion panel, and with two diffusion panels attached. The softlighter is mounted on an Interfit S1 studio flash.

And for good measure, some full-length photos on the white seamless paper with the light at camera-left and no fill light or bounce cards.

Not the most exciting hour of photography for myself or for Ny. But very useful. If you find these comparisons helpful please consider helping to support this blog by purchasing my book Anatomy of a Studio Portrait or by purchasing lighting gear directly from Interfit Photographic where you get a 10% discount and I get a small commission if you use the code CORNICELLO10 (in all caps) during the checkout process.

Umbrella Lit Portraits

As noted previously, I will be talking about keeping things simple in the Interfit Photographic booth at WPPI 2018. Most of it will be about working with umbrellas. Below is a gallery of images made in the studio and on location using an umbrella as my main (usually only) light source. 


Battle of the Round Modifiers

Does the shape really matter? Does diffusion help?

When you think of modifiers for your photo studio lights, what comes to mind first? Softboxes? Octaboxes? What about umbrellas? I will be at WPPI 2018 next week presenting about keeping it simple in the Interfit Photographic booth. I will be there on Monday afternoon at 1:30 and will primarily be talking about working with umbrellas. Think simple and inexpensive.

Yes, softboxes and octaboxes are everybody's favorites. But back in the "good old days" when I got started umbrellas were the go-to modifier. Some photographers were starting to build their own softboxes out of wood or foamcore, but there weren't any commercially mass produced boxes. Over the years it seems that umbrellas have fallen out of favor or have become 2nd class or even 3rd class options for modifying lights.

Like most everyone else, I've been using rectangular and roundish boxes for the past few years. But I have also maintained my relationship with one set of umbrellas, the Photek Softlighters in three sizes, 36-inch, 46-inch, and 60-inch. If I could only have one modifier, it would be the 60-inch Photek Softlighter. But having only one modifier is a scary fantasy notion, so let's not think of that any more.

How different are they from each other?

While preparing for my presentation I started thinking of the differences between the various modifiers. Do they really make that big a difference in comparison to their prices and their ease of set up and use? So I set up my tripod, and a remote shutter release this morning then started a series of selfies with a variety of round(ish) light modifiers. I grabbed these seven items and got to work: Westcott Apollo Orb, 36-inch Photek Softlighter, 41-inch silver metallic umbrella, 46-inch Photek Softlighter, 41-inch white satin umbrella, a 43-inch white shoot-through umbrella, and a 36-inch Paul C. Buff folding octabox (modified with a Bowens S-mount speedring). I mounted each of these in succession on an Interfit Honey Badger and you can see the results below. Use the slider over on the right side of the photos to drag left to reveal which modifier was used for each image. Each row is different modifier or different arrangement of the modifier with the full frame on the left and a close in crop on the face on the right to better see the catchlights in the eyes. Can you identify each modifier before dragging the slider?

I metered each modifier setup to read f/7.1 and kept the camera (Canon EOS 6D with Canon 100mm f/2 lens) on the "Daylight" white balance. As you can see, some of the modifiers have a strong influence on the color. The shoot-through umbrella was quite blue--maybe it doesn't have a UV coating? The Buff 36-inch octa was quite warm. The rest of the modifiers were much closer in color to each other.

Comparing the Photek Softlighter with and without diffusion

I was especially interested in seeing the comparison between the 46-inch Photek Softlighter on its own (without the diffusion panel), with the diffusion panel, and with 2 layers of diffusion panel. So here is that comparison. What do you think?

The image on the left below is the Softlighter with one layer of diffusion. The image on the right has two diffusion panels layered over each other.

So, how did you do on identifying each of the modifiers? Let me know in the comments here or join my lighting group on Facebook.



Size and Distance

Photography is a balancing act


Yes, a balancing act in many ways. Shutter speed vs aperture vs ISO vs amount of light is what most people probably think of. But it also plays a big role in the character of the light we use on our subjects. Today is a tale of two umbrellas. The first is a 84-inch reflective and the other is a 36-inch reflective. As you can see, the larger umbrella surface is a bit more diffuse than the smaller, satin-finish umbrella. But I am not concerned with that today. For now, I want to talk about size vs distance.

Inverse Square

Let's start with a refresher on the Inverse Square law. "the intensity of an effect (in our case, light0 changes in inverse proportion to the square of the distance from the source." For example, if we have a point source light at 2 feet from a subject and we back the light up to 4 feet away (doubling the distance), we end up with 1/4 the amount of light on the subject, a loss of 2 stops. Double the distance equals one quarter the light. 4 is the square of 2. 

Have I lost you yet? 

In practice you don't have to remember any of the math. For one thing, we rarely work with a point source of light in our photography. Our lights are either larger on their own or are modified with softboxes, umbrellas, diffusion screens, etc. So moving these larger lights closer or farther from the subject has less effect than the law would suggest. I think that photographers can narrow and simplify the meaning of inverse square down to saying that the closer your light is to your subject, the darker the background will be. Or you can turn it around and say that the farther your light is from the subject the brighter the background will be.  Is the glass half full or half empty?

Here is a set of images photographed against a white background. The subject (yours truly) is 24 inches away from a white seamless paper backdrop. The photos labeled 1 are lit with the 84-inch umbrella and the photos labeled 2 are lit with the 36-inch umbrella. The A images are with the light at 84 inches from the subject and the B images have the light at 36 inches away.

There are a few things that I want you to take notice of in these photographs. Starting with 1A and 1B you can see that with the big umbrella backed up away from the subject (1A) the face is lit flat and the catch lights (the reflection of the lights in the eyes) are small and bright. When the light is brought in closer (1B) the face start to have more contouring as the light falls of quickly in intensity and the left side (camera right) of my face is darker. At the same time, the catch light became larger and much less bright. Because the umbrella is so large the changes are a bit on the subtle side. In the closeup crops you can see that the background on 1B is a tiny bit darker than in 1A.

Now take a look at the bottom row. With the small umbrella backed up (2A) again the face is lit flat with small bright catch lights. In 2B with the light in closer the face again has more shadow area and a more defined transition from the properly exposed parts of the face to the shadows. 2A has a distinct shadow on the white background because the 36-inch umbrella 7 feet away is a relatively small light source. When moved in closer for 2B it becomes larger in relation to the subject and helps fill in the shadow, but not as much as the larger umbrella fills in on 1B.

Let's go back to the catch lights. Catch lights are specular reflections. That is, they act like a mirror of the light that creates them. They are the same brightness, no matter the distance from the light. Does this counter the inverse square law? No! Specular reflections follow the inverse square law in a different manner. While their brightness stays the same, their size varies in relation to the distance. When the light is farther away (1A and 2A) the light is small and bright. In closer (1B and 2B) the light is larger and dimmer. 

But wait! I just said that the brightness remains the same, how could it be dimmer? That is because when we bring the light in closer the overall exposure (the diffuse reflection--the skin, hair, etc.) gets brighter. The face got brighter while the catchlights stayed the same. To compensate for that and not overexpose the skin we have to lower the overall exposure. In this case with electronic flash, I turned down the power on the flash to bring the overall exposure back to normal. Turning down the power reduced both the diffuse reflection and the specular reflection, bringing them more in line with each other. Moving the light in closer also helps with other hot spots, such as highlights on the tip of the nose or a shiny forehead. Instead of lowering the flash power I could have  stopped down the lens more. But that would have changed depth of field, which I usually do not want to do. If this was lit with continuous light I could have changed the shutter speed, as well, to control the exposure.

Bright vs Harsh

At first it may seem counter-intuitive. Bringing the light in closer makes it brighter, but it also makes it softer (unless it is a inherently small light, such as a speed light (camera flash). Bringing the light in closer makes it larger in relation to the subject and allows the light to come in from more angles, filling in its own shadows. Don't equate brightness with harshness. We control the brightness via our exposure settings. We control quality (hard vs soft) with the size of the light. We control the depth of the light with the distance. This is why modifiers come in so many sizes. That lets you decide on your aperture first for the depth of field that you want. Then you set your light to subject to background distances for the depth of light that you want. Then you select the modifier size for the character of light you want. And finally set your exposure via the power of the lights. It is all a balancing act.

Questions or comments? Please use the comment box below or join my Facebook studio lighting group.





How white is white?

No need to blow it out!

Photographers are often called on to provide a portrait or a product photo against a clean white background. It is a nice clean look. But it can go bad quickly if you aren't careful. You can go from a clean, crisp, and sharp image to one with muddy edges, lowered contrast, and lots of flare.

So, just how white do you need to make the backdrop? Let's start with the backdrop. My choice is Savage Universal seamless paper. Savage offers three different white papers. White, Pure White, and Super White. Of these, I prefer Pure White. "Regular" white is a bit on the warm side. Super White has extra brighteners and might go a bit to the blue side in some situations. Pure White tends to stay neutral in various lighting setups.

Now that we have the backdrop selected we have to decide if we need to light it separately from the subject, and if so, how to light it. In many situations we are going to want to light the backdrop to keep it white and not turn gray. For individual subjects we can often get by using one light on the background. For groups we will probably need two lights, one from each side.

With that choice out of the way, we need to figure out how to expose the background. I've seen online discussions where the "experts" say to make the background 2 stops brighter than the subject to make sure the background goes white. Please don't do that!! The paper is already white, so in theory it could get the same amount of light as the subject and be white. For a little bit of insurance, you can overexpose the white background by 1/3 to 1/2 stop brighter than the light on the subject. Once you go past that you can easily have too much light bouncing back off the background and washing out the edges of the subject, especially their hair. A little bit more exposure and there is an overall haze and loss of contrast. If this is the look you want, then go for it! But in many situations this is a recipe for failure. Let's look at this series of images. All are photographed on white seamless with a 2x3-foot softbox on the subject (yours truly) and a separate light with a 7-inch metal dish reflector on the backdrop.

For each image I took a meter reading at the subject and at another reading at the backdrop. In the first image both read f/10. I added a white border on each side of the photos and you can see that in the first image the background is close to but not pure white. And yes, I let the backdrop fall off from left side to right. I could have pulled the background light farther away from the paper to make it more even, but I was more interested in showing the effects of exposure. The second image has the background reading f/13, which is 2/3 of a stop brighter than the subject. Here you can see that the background on the left side of the image is now almost as white as the border, but there is still good contrast in the image. Strands of flyaway hair can still be seen. If you had to, you could easily brighten the background a touch in Lightroom or Photoshop to be as white as the border.

Foreground and background metered to the same exposure

Background metered 2/3 of a stop brighter than the foreground

For the third image I bumped up the background exposure another 2/3 stop to f/16, so now a full stop and a third brighter than the subject's reading. Still okay, but starting to lose the few remaining hairs on the top of my head. Image four has the exposure up another stop to f/22 and overall contrast really starts to suffer.

Background 1-1/3 stops brighter than the subject, approaching the troublesome area of overexposure

Background 2-1/3 stops brighter than the subject, starting to flare out and lose contrast


Finally, another 2/3 stops extra exposure to f/29 and you can really see the damage from the blowback from the overexposed white paper backdrop. And for good measure, an image where I turned off the background light and let the paper fall off to gray so absolutely no effect from the background on the subject.

A full 3 stops overexposure really shows the problem of flare and blowback.

Here is what it looks like with no light on the background

If I were to move farther away from the background and bring the light on the subject in closer I could make the white background go darker, possibly even to full black. Or I could change out from Pure White to a dark gray. Here I switched to Charcoal paper with no light on the background. And in the final image I kept the Charcoal paper, but put a light on it and overexposed it 3 stops at f/29 almost turning the Charcoal to white, but nowhere near as bad as overexposing the white paper background. 

Charcoal seamless paper with no light on it

Charcoal seamless paper overexposed 3 stops

There you have it. No need to wildly overexpose your backdrop to get white paper to look white. That means you can use a less powerful light, and you can have faster recycle time on your flash, and if using battery power, get more flashes. All while maintaining edge detail and good contrast in your photographs. 

I hope this helps you get clean white backgrounds without degrading the subject in front of it. You can find more information about how lighting works in my book Anatomy of a Studio Portrait and/or you can join in discussions about working in a small or home studio in my Facebook Group

Go out and light up the world!

Perspective (AGAIN!)

Here we go again!

First thing. Distortion and perspective are not the same. In lenses "distortion" is defined as an aberration where the corners of an image projected by the lens pull outward (pincushion) or the corners pull inwards (barrel). Distortion is independent of focal length. It is controlled in the design of the lens and is affected by the placement of lens elements and the placement of the aperture diaphragm inside the lens. It cannot be corrected by anything you do with your camera. It is built into the lens. Post-processing software often provides tools to help correct distortion. Most lenses are corrected as much as they can be for distortion. Rectilinear lenses attempt to keep straight lines straight across the image plane. Wide angle rectilinear lenses do have a characteristic of stretching objects at the edges of the frame. this comes from trying to fit a very wide almost unlimited view onto a fixed size image sensor (or film). This is usually most noticeable when the camera is in very close to the subject. The cure for this stretching is to use a fisheye lens! But that introduces a whole set of other issues for another discussion.

An interesting point about this "wide angle distortion" is that it only affects 3-dimensional subjects. Let's take an example of a tennis ball photographed with a wide angle rectilinear lens. If the tennis ball is in the middle of the frame it appears perfectly round. If it is move off to a corner of the frame you can see that it gets stretched out into an oblong shape. However, if you make a print of the centered ball and put the print in the corner of the frame in place of the actual tennis ball the ball in the print remains round. 


But enough of that, it is just a distraction from what I want to talk about. If you want more information about lens distortion I invite you to take a look at this article from Zeiss

On to Perspective!

I seem to be on a perpetual quest to help photographers understand the affect on perspective caused by camera to subject distance and how it is not related to focal length. Perspective here is defined as the relationship between objects in the scene. Objects closer to the camera appear larger than objects farther away. Objects closer to the camera also appear farther apart from each other than do the object farther away. It doesn't matter what focal length lens you use. All lenses show the same perspective from the same camera position.

So, you ask, what about telephoto compression? Isn't that caused by using a long lens? No! Go back to the previous paragraph. Looking at it from the other direction, it says that objects further away from the camera appear to be closer to each other than objects closer to the camera. Focal length doesn't affect that. Focal length affects magnification and the field of view (how much of the scene fits into the frame). You don't even need a camera to see how this works. Go someplace that has a series of similar items spaced out evenly in front of you. Maybe a long stretch of road with street lamps or something like that. Stand a foot or two from the first object and notice the distance to the second object. Pretty far apart. Now concentrate on the 8th and 9th objects. They look closer together and more similar in size. There is your compression. Of course, you took your camera with you anyway. So put the camera on a tripod and take a photo with a short lens and another photo with a longer lens.

Take those two photos into your favorite photo editor and crop the photo taken with the short lens to match the image taken with the long lens. You will see that for the area of the photo that is common to both focal lengths the perspective (and compression) are the same. When we want to show this compression we, of course, will pick a longer focal length lens as cropping optically maintains image quality as opposed to digital cropping or making an extreme enlargement from film. Changing the lens just changed the magnification, though, not the perspective.

Here is a set of images from a train station in Kyoto, Japan. All were made from the same camera position at various focal lengths rom 18mm to 400mm.  Notice that perspective in the area outlined in purple, which is common to all of the photos, remains the same.

People, too!

The same thing happens in our portrait work. From the same camera position your subject will look the same (except for size) if photographed with a 10mm lens or a 100mm lens. Take a look at the following image. It shows a studio scene made with a 10mm lens on a full frame (35mm) digital camera. The camera is fixed on a tripod at 58 inches from the mannequin. If you drag the slider from the right side to the left you will reveal an image taken with a 100mm lens and resized down to match the size from the 10mm lens. Notice that the perspective on the face is exactly the same from both lenses, despite the vast difference in focal length.

Here we see the same setup photographed with an 85mm lens next to the setup photographed with the 10mm lens. Again, the perspective is the same.

 85mm lens, not cropped

85mm lens, not cropped

 10mm lens, cropped 

10mm lens, cropped 

Here is a set of photos made with the following lenses: 100mm, 85mm, 50mm, 35mm, 24mm, 20mm, 16mm, 15mm fisheye, and 10mm. Despite the extreme barrel distortion bending everything but the center of the image, even the 15mm fisheye shows the same perspective on the face (see below).

100mm, 85mm, 50mm, 35mm, 24mm, 20mm, 15mm, and 10mm from the same camera position 58 inches from the subject

Here are the 85mm and the 15mm fisheye cropped to the same framing...

 85mm full frame

85mm full frame

 15mm fisheye cropped

15mm fisheye cropped

For another take on this, please visit my previous post about the Incredible Shrinking Space Needle that is an excerpted from my book, Anatomy of a Studio Portrait, which is available on Amazon

And a quiz of sorts... 

This is also from Anatomy of a Studio Portrait.Can you tell what focal length lens was used for each of the above images?

From left to right, top to bottom: 200mm, 135mm, 105mm, 100mm, 70mm, 57mm, 38mm, and 24mm.



To round things out, all of the photos in this set were made with the same 24mm lens, but the camera to subject distance was changed attempting to maintain the same size head in each image. Distances are 20 inches, 24 inchces, 28 inches, 39 inches, 51 inches, and 60 inches.

What about full frame vs crop frame?

Easy enough. Same setup with two cameras. Full frame (Canon 5Diii) with a 50mm lens and a 1.6 APS-C (crop) frame (Canon EOS M5) with a 35mm lens. Camera to subject distance is the same (36 inches) in both photos. The facial features are the same.

 50mm lens on full frame camera

50mm lens on full frame camera

 35mm lens on APS-C "crop frame" camera

35mm lens on APS-C "crop frame" camera

Let's take it further and compare the 50mm lens on full frame with a 10mm lens on crop frame...

 50mm on full frame again

50mm on full frame again

 10mm on APS-C cropped to match

10mm on APS-C cropped to match

I hope this helps explain how distance affects perspective. Yes, you can get very widely different perspectives by using different focal lengths, but that is when and because you move the camera. Telephoto (long) lenses tend to make us back up away from our subjects making the scene look more compressed. Wide angle (short) lenses invite us to move in closer to our subjects making the scene feel more wide open. It is our moving in and out, though, that changes the perspective. The focal length of the lens then determines how much of the scene will be captured.

For even more on this topic, please visit the Understanding Camera Lenses article at Cambridge In Colour. And take a look at the other tutorials there. Sean McHugh does a great job at explaining photographic concepts with text, illustrations, and calculators.



Diffusing on-camera flash

What does diffusion on a speed light do?

I keep seeing photographers talk about diffusing their on-camera flash. Whether it be with a handkerchief, a Stofen diffuser, the built-in pop-out diffuser panel, or some other form of diffusion taped over the light, I am not quite sure what they are trying to accomplish. These various diffusers are used to spread out the light coming out of the flash, basically to allow the flash to be used with a wider angle (shorter) lens. The light spreads out to cover more of the scene at the cost of loss of power. 

Quality or character of light?
Some that I talk to say that they use the diffusion to soften the light--to make it look better. I question this. We are talking about diffusion methods that pretty much keep the flash the same size as it is without the diffuser. We should all know that to make a light softer you have to make it larger in relation to the subject it is lighting. A larger light source provides light from more angles allowing it to become its own fill light to soften the edges of shadows. There are devices like the Gary Fong diffusers or the Roque Flash Benders that do make the light larger. I am not talking about those here. Just diffusers like those shown here...

 Straight flash, diffusion material taped over flash, and Stofen Diffuser on flash

Straight flash, diffusion material taped over flash, and Stofen Diffuser on flash

Here are two photos of my favorite mannequin (models are hard to come by in the middle of the night when I get inspired to write these blog posts). One photo was made with the straight flash and the other was made with the 1-stop diffusion material taped over the light. Can you easily tell which is which? All of the photos were made in TTL mode at +/- 0 stops with no post-processin except for white balance. 

Two more examples, with a longer lens...

I am not seeing it
My argument is that diffusion right on the speed light, which doesn't make the light source significantly larger, does not soften the light. The only slight exception might be if the wider distribution of the light allows it to bounce off a low ceiling or close by light color walls. But even that will be extremely subtle. To me, these methods of diffusion only do a few things, none of them beneficial. They make the flash have to work harder, putting out twice as much light (1 stop), while increasing recycle time and draining battery power. 

Look closely at the shadows in each of the photos. A softer light creates a softer, more gradual transition from the true value of the subject to the underexposed shadow areas. In these photos the shadow edges look the same. There is no softening of the light. 

What is your experience with diffusion and speed lights? In the above examples, photos labeled B (on the left) have the diffusion in place. Photos labeled A (on the right) are straight flash. Is there enough difference between A and B to justify the loss of light power and the extra drain on batteries? 

 Index card diffuser

Index card diffuser

But, but, but...
OK, you say. These are close in portraits. What about something more like at an event or reception. Here are six photos taken with an on-camera flash with a 28mm lens about 11 feet from camera to the subject (me!). Straight on flash, diffusion material over the flash, the built-in diffusion panel, a Stofen pointed straight ahead, the Stofen with the flash pointed up at the ceiling, and with a white index card taped to the pointing up flash. This time I did not correct the white balance, these are all "out of camera." All TTL exposures at ISO 400 and f/5.0.

This post is not anti-speed light. I think you can get some very nice light from speed lights--even when mounted on the camera's hot shoe. The following photos were all made using an on-camera flash that was pointed off to the left to bounce off a wall, effectively making the light much larger and thereby softer. 


Feathering your light

For my fine feathered friends!


Back again to help clarify studio lighting terms. This time I am taking on the concept of feathering. Feathering is pointing the light ahead of your subject instead of straight on to your subject. Feathering usually produces a nicer looking image. People often say a "softer" light on the image, but that isn't quite correct. Remember that the quality or character of light is determined by the size of the light in relation to the subject. You see this in the shadow edge transition. The larger the light source is the smoother the diffuse highlight to shadow transition is and the softer the light is.

Let's take a look at what happens when you feather the light. Here are photos of a 2x2-foot softbox straight on and the same softbox feathered off to one side. What do you notice first? I hope you see that the feathered light is SMALLER than the direct light. So, if the light remains the same distance from the subject, it is potentially slightly harder when feathered. But at the same time, it spreads out more across the face of your subject, giving a more pleasing look. 

 Straight on the softbox is larger than when feathered

Straight on the softbox is larger than when feathered

Hard Light

Working with a softer (larger) light source it isn't so easy to see what is happening. Let's start with a harder light. This time a 7-inch standard metal dish reflector. 

7-inch reflector straight on and feathered 

Take a look at the 3 points labeled in the photo. A (the nose), B (the lower lip), and C (the ear).  A is the same brightness direct and feathered. Why? Because it is a specular reflection and is the same brightness as the light source, no matter the distance. If the light was moved in closer the brightness would stay the same but the reflection would get bigger. If the light source was moved back the brightness would again be the same, but the reflection would get smaller. The feathering doesn't have much of an effect here.

B is somewhat similar with the small hard light source. Basically the same straight on or feathered. At point C we can see that pointing the light more in front of and across the subject a little bit of light catches the ear. I would probably retouch out that little highlight on the ear. 

Go back to point A and the nose. This time look on the shadow side of the nose. The edge of the main dark shadow is about the same. With the feathered light the shadow is not as dense, but the edge transition line is pretty much the same. The feathering lowered the contrast, but didn't make a softer transition. It didn't soften the light.

Soft Light

Now let's work with a softer light. This time a 2x2-foot softbox. 

24x24-inch softbox straight on and feathered

The differences are more subtle, but they are there. Look at the same three points as before. The brightness of the specular highlight on the tip of the nose is the same brightness straight on and feathered. But this time there is a difference in point B on the lower lip. Feathering the light changed the shape of the wide highlight on the lip, but the brightness is still the same. The larger light also allowed more  light to reach the ear than with the 7-inch dish above. 

Again, I invite you to look at the shadow side of the nose. There is very little difference in the shadow edge transition. Feathering did not make it softer.

Comparison sliders drag to the left to see the feathered light, drag to the right to see the direct light

Hard vs Soft

Below are the feathered light images with the small and the larger light sources

Comparing the 7-inch and the 24-inch light sources

Look at the same points again. A is pretty close in brightness, but the shadow edge on the shadow side of the nose is very different. That comes from the difference in the size of the light sources, not from the feathering. The larger light makes for a nicer looking highlight on the lower lip (B). If I had move the softbox back further away from the face it would have been smaller and brighter. Brighter because the rest of the face would have received less light and I would have to have compensated by turning up the power of the light (strobe) or used a longer shutter speed (constant light, which is what I used for these demonstrations). As noted above the specular highlight remains the same brightness, but I would have had to brighten up the entire image, including the specular highlight to maintain proper exposure on the face. I know that  this can be confusing. So let's look at another illustration.

Controlling the size and brightness of specular highlights

Again I am using a constant light, so I am controlling my exposure via my shutter speed. If I was using flash here I would vary the power of the flash to maintain the same exposure on the subject of the photo. With the light 40-inches from the can the highlight is thin and bright--too bright to read the text on the label. As the light is brought in closer a couple of things happen. 1. The highlight gets wider because the light is closer and therefore larger in relation to the subject. 2. I have to lower the overall exposure so the diffuse reflection of the can is properly exposed. This brings down both the overall exposure and the specular highlight brightness, bringing them closer in line with each other. In the third image the light is very close and its reflection is even less noticeable because it is spread out over a larger area and the brightness of the rest of the can has been brought up closer to the brightness of the highlight (and then the overall exposure was lowered to bring it all back to give the proper exposure of the overall subject). I know this can sound counter-intutive. Bringing the light in closer reduces the mirror-like specular reflections.

We see the Inverse Square Law doing its thing here. As the light is moved closer to the subject it falls off faster and the background gets darker. As the light is moved in closer the specular highlight remains the same brightness, but gets larger. As the light is moved in closer the overall diffuse reflection exposure gets brighter and we have to lower the intensity of the light.


Feathering your light can change the size and shape of specular highlights, but the brightness will stay the same. Feathering your light will help even out the exposure across your subject, but won't have much effect on the shadow edge transition (softness). Feathering your light is the right thing to do. If you want to tone down a hotspot you need to move your lights in closer. But that also affects the depth and spread of the light. So many tradeoffs in photography. More details about the tradeoffs are in my book, Anatomy of a Studio Portrait.

Thanks again for stopping by!
John Cornicello