contrast

Environmental Report #2

The white “cave.” A similar setup was used for the dark environment.

The white “cave.” A similar setup was used for the dark environment.

What a difference the space makes

In our previous episode I compared various modifiers used in a very dark environment which limited the light being able to bounce off of surroundings to fill in shadows and reduce contrast. Today I am comparing the same modifiers used in a small white space versus used in a small black space. The environment was controlled by building a cave made of foamcore v-flats in the studio. In one “cave” the walls, ceiling, and floor were black. In the other they were white. Too often photographers neglect to take into account the environment they are working in, especially when using studio strobes. We know that the strobes will overpower the ambient light, but the walls, floor, and ceiling will still have an effect on the outcome.

The effect is on the shadow density or the contrast in the image. We know that a larger light source, as seen by the subject, gives a softer light by stretching out the shadow edge transition and filling in the shadows. If the size of the light doesn’t change, the environment has an additional effect on the shadows without affecting the shadow edge transition. This gets confusing. As you will see, the photos made in the white surroundings could be described as softer, even though the shadow transitions are the same. Just as we shouldn’t confuse harshness with brightness, we shouldn’t confuse quality with contrast. We can have a small hard light that is diffused (spread wider) or more focused. We can have a large light that is more focused or spread out more. Diffused doesn’t equal soft. Diffusion spreads the light to cover a wider area. And in doing so it might bounce off of walls to lower contrast. And that might look softer, but in a dark environment we can see that this isn’t true. The size determines the quality (hard/soft) and the diffusion and environment control the contrast.

Let’s look at some of the comparisons.

Same modifier, same distance, totally different look due to the environment. With the white surroundings the light bounces all around and fills in the shadows. The shadow edge, though, is the same quality due to the size being the same.

Same modifier, same distance, totally different look due to the environment. With the white surroundings the light bounces all around and fills in the shadows. The shadow edge, though, is the same quality due to the size being the same.

Here is a 36-inch deep parabolic softbox (16 ribs). Again, a totally different look by changing the environment.

Here is a 36-inch deep parabolic softbox (16 ribs). Again, a totally different look by changing the environment.

Here with a smaller, harder light source, an 11-inch deep metal dish reflector it is easier to see the shadow edge quality remaining the same while the density of the shadows (contrast) changes depending on the environment.

Here with a smaller, harder light source, an 11-inch deep metal dish reflector it is easier to see the shadow edge quality remaining the same while the density of the shadows (contrast) changes depending on the environment.

The same modifier as above (11-inch deep zoom) with a diffusion sock on it. Little difference between the open face and the diffused face in the black surroundings. But when in a white room the shadows open up much more with the diffuser spreading the light to bounce off the walls. But the edge transition range is still the same.

The same modifier as above (11-inch deep zoom) with a diffusion sock on it. Little difference between the open face and the diffused face in the black surroundings. But when in a white room the shadows open up much more with the diffuser spreading the light to bounce off the walls. But the edge transition range is still the same.

With a narrow, controlled light, such as from a snoot, there is less difference between the two environments. The light isn’t allowed to spread out to bounce off the walls, so contrast is similar.

With a narrow, controlled light, such as from a snoot, there is less difference between the two environments. The light isn’t allowed to spread out to bounce off the walls, so contrast is similar.

OK, so much for light vs dark environments. What difference does diffusion make vs. undiffused in the same environment? Let’s take a look at the 60-inch Photek Softlighter with and without its diffusion panel in both environments.

Here in the white cave we see the Softlighter with its diffusion panel on the left and without the diffusion panel on the right.

Here in the white cave we see the Softlighter with its diffusion panel on the left and without the diffusion panel on the right.

And now the same comparison in the black cave.

And now the same comparison in the black cave.

I will leave it up to you to decide how much of an effect the diffusion panel has with the Softlighter. Tell me what you think in the comments below.


Thanks!
John

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


Don't confuse contrast with quality of light

One more time with feeling!

We are coming to the end of my 10-week intro to studio lighting class and I still see confusion between light quality (determined by the size of the light) and contrast (determined by the environment).

Basically, contrast is the depth/darkness/density of the shadows. It is controlled by the environment. If there is a lot of light bouncing around off of the walls, ceiling, floor, or other nearby surfaces the shadows open up. Adding a diffuser to your light spreads the light out to bounce off all those objects to lower the contrast. The bigger and darker the environment you are photographing in, the more contrast you will have. Narrow beam reflectors and grids can be used to control spill (the opposite of adding diffusion) and maintain or increase contrast when working in smaller spaces with light color walls, ceiling, etc. Please, do not add diffusion material in front of your grids!

Quality of light is the transition from highlight to shadow. It is controlled by the size of the light. The larger the light is as seen by the subject, the softer the light is as the light hits the subject from many angles and provides its own fill light. Yes, it lightens the shadows, but the main thing is that it does away with the abrupt edge that you get from a smaller/harder light. 

Adding a diffuser such as a scrim or a shower curtain some distance in front of a small light source turns it into a larger source, making the light softer. But diffusion right on the light (which doesn't change the size of the light) will not change the quality of the light. While the shadow is less dark, it still maintains a hard edge if the light source is small.

Some pictures to help explain…

Diffusion yet again

I just can’t stop…

In my last post I mentioned that adding diffusion at the same size as the light source will not soften the light (change the shadow edge transition), but will change the contrast. Adding an additional layer (or more) will still maintain the same light quality, but spread it out a little bit more and also lose a lot of power.

That got me to wondering just how much light is bouncing around the room to add to lower the contrast and fill in those shadows. Obviously in a very large studio with black floor, walls, and ceilings there will be nothing to bounce off of. Similarly if working out doors in an open field there will be no extra fill. But I am working in a modestly sized room with an 8-foot white ceiling, a light natural wood floor, and white walls.

Time for another test!

The Interfit Deep Zoom Reflector

The Interfit Deep Zoom Reflector

Here are three images made with the Interfit Deep Zoom reflector. The first image is with the “bare” reflector. Next is with the included diffusion “sock” and the third image has a sheet of diffusion material added to the front of the modifier for “double-diffusion.” I kept the camera settings at ISO 100, SS 1/160 sec., and F/9 so that the ambient light effect on the image would remain the same. I raised the power of the flash in each image to compensate for the diffusers and to maintain the same flash exposure.

Click to enlarge

Here you can see that the shadow edge changes slightly from bare reflector to diffused reflector as the light is homogenized from multiple sources (flash tube, glass dome, reflector) all contributing their own shadows to one source (the diffusion material). And you can see that the shadows open up a little bit and the background gets a little bit brighter. Comparing the second image (single diffuser) to the third (double-diffuser) note that the shadow edge that determines the light quality is exactly the same. The diffusion is the same size as the light. If the light size doesn’t change the quality of light doesn’t change. What changes here is how much power you need from your lights to compensate for the light loss from the multiple diffusers. Again, don’t confuse contrast with quality (hard or soft) of light.

Now go out and light up your world!

John



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

DANGER ZONE!

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!
John