I Won!

From the Portland Metro Photographic News...

"Congratulations to Seattle-based photographer and PMPN member John Cornicello on your winning SCARY photo.  The judges agree that your image was the best interpretation of PMPN's Halloween theme.

"One judge commented: "Actually made me jump when the picture opened up full size! Excellent photo-illustration.""

My thanks also go to Lara Paxton for modeling, hair, and makeup. Thanks!!

My "Friends" project on Facebook

For the past few weeks I've been inviting friends over to take some photographs. I usually say "portraits," but that isn't quite descriptive enough for some of them. I encourage costumes and makeup. A chance to let go and have a really fun photo session. Here are a few samples. You can see all of them on Facebook.

Thanks for taking a look. And call me when you're in the neighborhood. We'll get you into the project!

Light to subject distance

Its not just about the size.

Yes, quality of light is often determined by the size of the light. But size alone isn't enough, you also need to consider distance. A 24" square softbox about 18" from the subject is beautiful. The same 24" softbox move back to 8 feet from the subject isn't so beautiful. Let's look at some of the reasons why.

When setting up your lights, you have two creative decisions and one technical. Aperture and light-to-subject distance are your creative choices. How much (or little) depth of field do you want? Select the Aperture for that. What quality of light do you want? Select your light size and distance for that. That leaves you with one more setting. You have to match the power output of the flash to give the proper exposure at your selected aperture. If you want to take the photograph at f/5.6 and your flash meter reads f/8 you have to lower the output of your flash by 1/2 (1 stop). If you move the light back you change the quality of the light. Unacceptable. If you leave the light and stop down, you have a different look and feel to the image. Also not acceptable. So you have to change the power on the flash.

At 18" away, the light is large relative to the portrait subject's head. Its light wraps around the subject and gives a nice smooth gradient falloff around the contours of the subject. The light/shadow edge (shadow edge transfer) is soft and smooth. When moved back a few feet from the subject the light is relatively small, it needs to be more powerful, and its light no longer falls off quickly. The light in close is soft and contrasty, with soft shadows. The light far away is hard and flat, with harsh shadows. At first this sounds contradictory. Contrasty with soft shadows? Flat with harsh shadows? In close the light wraps around the subject and falls of smoothly from the highlight to the shadows, providing lights and darks. Yet there is little shadow from the nose or eyebrow ridge. The smaller light, further away, gives a more even (flat) light across the subjet (less contrast), but is not close/large enough to wrap around contours like the nose, giving dark shadows on the opposite side from the light.

Now that the size/distance is coming clear we need to think about how much light there is. What do you set the power level to on your flash? This is something I don't think a lot of photographers take into consideration. Its main effect will be in specular highlights, such as oils on the skin or the catchlights in the eyes.

Specular highlights are not subject to the inverse square law, which says that when you double the distance between the light and subject the subject receives 1/4 the light (the light has to cover an area 4 times the original, not 2). But we're not talking about overall area here (the diffuse reflection). We're talking about the mirror-like reflection of the light source. Those stay the same no matter the light to subject distance. In an extreme example, we can look at a mirror and a light. Photograph the reflection of the light in the mirror with the light 12" away. Then photograph the same light reflection in the mirror, but from 10 feet away. The bright specular reflection of the light will be the same brightness. The rest of the scene will be much darker. But the light in the mirror remains the same.

So, you ask, why do we bring the light in close? Because in close we can lower the power to get the same exposure. Lowering the power lowers the light output. So up close that catchlight in the eye or the highlights on the skin are lessened. Additionally, because the light is in close and large, these reflections get spread out and even out. Instead of a bright hotspot on the tip of the nose, there is a nice even glow across the entire face.

In the above samples the light to subject distance was changed, the power on the flash remained constant, and the aperture was changed* to maintain the same exposure. Pay particular attention to the mannequin's right cheek, the tip of its nose, and the lips. In the first image, with the light further away (smaller) you see bright highlights in these spots. As you move to images b, c, and d, the light was moved closer, becoming larger. In doing so you will notice that the highlights spread out more and the overall look is softer.

This is something to consider when purchasing studio strobes. Too often the first thing a new photographer asks is "how powerful is the light?" Should I get 600 watt seconds? 1200? 2400? More? In some situations, a lot of power is necessary. So it is a good question. But the question I usually find myself asking when shopping for lights is "how low can I set the power?" and "what affect on color and flash duration does this have?" The more expensive flash units will usually offer better consistency (the flash color doesn't change when power levels change) and will offer a wider range of power settings. Some less expensive units may just offer a 2- or 3-position rocker switch (full, 1/2, 1/4). While more expensive units may have a variable slider or dial so you have more control to get just the power level you want.

Bringing the light in close also helps pop the subject out from the background. It also lets you light the background independently of the subject. Being in close, the light falls of quickly (go back to inverse square). The light falling on the subject doesn't have enough power to reach the background. The background stays dark so you can light it separately to give the scene contrast that you desire. You can also use other controls on the background (color gels, a spot light, grids, etc.).

Going back to the example image above, you see how the background is lit by the single light source in example A. But when moved in close, as in example C, the background has gone completely black. If you want, you can light the background completely separately now with a spot, color gels, etc.

As you move the light further away from the subject you have to raise the power to maintain the desired aperture and the light spreads out more. Where in close the light only fell on the subjects head and shoulders, moved back it covers their entire body and also spills onto the floor and background giving a flatter, blander image. For this reason, a larger light further away is not the same, even though the size relationship to the subject might be the same. A 24" square light at 24" away from the subject may have a similar light quality to a 48" square light 48" away on the subject, but the rest of the scene will be noticeably different. The light further away will produce an overall "flatter" image with the light spilling onto the background and periphery of the subject.

*Earlier, I mentioned maintaining aperture for creative control over depth of field. The two examples below are taken at the same aperture, but this time the lamp power was increased when it was moved further away to maintain the exposure. Note the same issues listed above. When far away, there are hightlights and shadows on the face and the background is lit up. In close the surface is smoothed and the background has gone to black.

Continuing on focal length

Just a quick demo/test/quiz. Here are two photos of a mannequin. The camera was placed on a firm tripod and did not move between the shots. Photo A was taken with a 300mm lens. Photo C was taken with a 16mm lens. Again, the only difference between the two is the focal length. The camera and mannequin remained stationary between the shots.

Now for the quiz. Photo B...

Which lens?

Answer, 16mm. But cropped in to show the same angle of view as the 300mm. Determination? The 16mm and the 300mm show the exact same perspective.

Photographs taken with different focal length lenses, but from the same camera position, show exactly the same perspective in the section of the scene that is common to all the different angles of view of the various lenses. Perspective is not affected by focal length, but by camera to subject distance. Short lenses appear to stretch perspective because we tend to use them from in closer. Long lenses appear to compress images because we almost exclusively use them from further away. We don't use long lenses in close because their field of view is too narrow and they often cannot focus as close as we would want. So we move back to get the framing we want, and thereby affect the perspective.

What would happen if we used the 16mm lens but moved in closer to fill the frame the same as the 300mm? Then we see the drastic perspective change...

Again, the perspective change is from moving the camera. The wide angle lens allows us to get in this close and be able to capture the full scene. But it doesn't cause the effect.

Considering Focal Length

Here is a piece that I wrote for the Seattle Photographic Society's Cable Releases newsletter this month:

The focal length of a lens determines the size of the image projected onto the film/sensor. It also determines the angle of view, the area of the scene which will be recorded. Different focal length lenses are given descriptions like normal, wide, ultra-wide, long, telephoto, etc. These are not absolute designations. For example, a 50mm lens would be considered "normal" for a 35mm camera, but would be a wide angle lens on a 6x6cm (medium format) camera. And 50mm would be considered a moderate telephoto on most (non full-frame) digital SLRs that have a sensor that is smaller than a 35mm fill frame.

The shorter the focal length of a lens, the smaller an object will appear on film (I will use the word film to describe actual film or a digital sensor in this article) when the subject remains at a set distance from the camera. Similarly, a longer lens will make the subject larger without moving the camera position. Focal length and image size are directly proportional. Double the focal length and everything in the image doubles in size.

Different focal lengths present different challenges to the photographer. Short lenses have a wide field of view and often include more of a scene than we really want unless we move in closer (which changes the perspective). Long lenses magnify more than just the subject. They magnify any camera movement causing blurs, leading to the necessity of using a tripod or other stabilization device.

Choosing a lens focal length is pretty easy when you are forced into the selection. If you cannot back up, use a shorter (wider angle) lens. If you cannot get closer, use a longer, narrower angle lens. There! The decision is made. Go take your picture.

But what about the creative side? When you do have options, which lens do you use? Sometimes you have all the room in the world to back up. But you might still want to use a wider lens because you want to get closer to your main subject, yet take in a field of view that shows the surroundings. Examples of this would be coming in close on a rock or plant in the foreground of a landscape scene. By coming in close you alter the perspective of the scene to make the foreground object appear much larger in relationship to the background (or the background much smaller in relationship to the subject). The use of the wide angle lens allows you to capture this. If you used a longer lens from further away you could get the same size for the subject, but the background would show less of the environment, helping isolate the subject. Both are viable treatments, but the looks are very different.

Conversely, you might be in a situation where you are able to walk right up to within inches of your subject. But instead you might select a longer lens to force yourself to move back from your subject, thereby giving you a more normal perspective on the scene. Most of the time we think of this in relationship to pictures of people (portraits). We want to stay a minimum of about 5 or 6 feet back from the subject of the photo so that their facial features are not distorted. We can keep our distance and take the photograph with any lens (the distortion comes from the camera to subject distance, not the lens). Here, the selection of lens focal length here will determine the framing. With a short lens at 6 feet we might get the entire person in the photo. If we want just their head and shoulders we have to crop in and lose quality due to the cropping and enlargement. We cannot move in closer, or things will distort. But if we select a longer lens (maybe 2 times the focal length for the "normal" lens for our film format (35mm, APSc, 6x6cm, etc.) we can maintain the working distance and fill the frame better. As noted above, moving back and narrowing the field of view also helps isolate the subject and make them stand out from the background.

What is not always so obvious is that the same thing applies to landscape photography. In my opinion, too many times a photographer puts on a short lens for a landscape image and is disappointed with the results. There is too much foreground or too much sky, or both. The image can often be improved by using a longer lens and moving back. This is not the same as cropping in. If the photographer kept the camera in the same position and switched to a longer lens it would have the same visual effect as cropping. But what I'm suggesting is moving back so that the perspective changes.

Here is an example. Take a field with a tree in the foreground and a house in the distant background. With a 50mm lens we stand 20 feet from the tree to render it a nice size in the image. But we find the house to be too small in the background. By moving back to 40 feet away and changing to a 100mm lens we find that the tree remains the same size because we balanced the the doubling of the distance with the doubling of the focal length. But the house is now noticeably larger in relation to the tree because the distance to the house has been changed a smaller amount. If the tree was originally 20 feet away and the house was 50 feet away, moving back 20 feet to 40 feet doubled the distance to the tree, but only changed the distance to the house from 50 feet to 70 feet. This is sometimes referred to as "telephoto compression," but is really based on the camera to subject distance, not the lens.

To zoom or not to zoom?
That is the question. While it is nobler in the eyes of some photographers to use prime lenses (fixed focal length, non-zoom lenses), I offer the contradiction that a zoom lens gives you much better control over the final image. Years ago zoom lenses were often of inferior optical quality, so prime lenses were required for the best image. But many of today's zoom lenses offer quality rivaling that of prime lenses.

We've all probably heard the saying, "zoom with your feet, not with your lens." I have to disagree. You cannot zoom with your feet. Zooming implies maintaining the relationship between objects in the frame. Once you start moving the camera, the relationship between objects changes. You set the camera to subject distance to give the overall look of a scene and set that relationship. You then select the focal length lens to fill the frame. With prime lenses you often cannot frame the scene exactly as you want it and have to later crop in post processing (digital or dark room) or move and change the photo. With a zoom lens you have the ability to keep the camera stationary and alter the focal length to get the cropping done in camera. If you zoom with your feet (move in closer or move back) you change the relationship between the objects in the photo (not necessarily a bad thing, but it is a different picture).

Photographic Seeing
Many book chapters have been written about the differences in seeing between eye and lens. I strongly recommend picking up one of the many books by Andreas Feininger written in the late 60s or early 70s for detailed discussions of this. I will offer here some of his observations:

1. While a lens mechanically reproduces everything within its field of view, the eye/brain combination consciously perceives only those aspects that you are momentarily interested in. It disregards and doesn't notice the rest of the scene. The lens is objective, the eye/brain is subjective. The photographer has to learn to pay close attention to everything within the image, no matter how insignificant or dull it might seem. It is always those "unimportant" parts of the image that ruin the photograph.

2. The visual impression is only a part of what we take in. There are sounds, smells, vibrations, and possibly other people around us that all contribute to what the eye/brain sees. The lens only captures the visual part. The photographer must learn to mute senses other than sight and then be satisfied that the visual aspect of the subject is enough to reflect its essence.

3. A photograph presents a subject taken out of context. There is a frame around it. Peripheral vision is cut off by the boundaries. No matter how important those peripheral influences are in real life, they are not in the photo. The beautiful blue sky doesn't help when you come in tight on a clump of flowers, though it might have been part of what drew you in to take the close up photo. The photographer must learn to evaluate his subjects on their own merits and disregard everything outside the scene.

4. Because our eye/brain works so quickly, we sometimes think that we see everything sharp simultaneously, no matter its distance. But the camera lens can only be focused on one specific plane at a time, showing objects in front of or beyond this plane increasingly blurred the further they are from that plane. And at the same time, the eye/brain can be very selective and let you concentrate on just a part of the scene, whereas the camera lens, when stopped down, will give equal sharpness to the entire scene and remove the concentration. The photographer has to learn how and when to control the sharpness.

5. The eye/brain can adjust automatically to brightness levels in a scene as we look around the scene. The lens diaphragm stays the same throughout the exposure, and can lead to both over- and under-exposure in the same scene. The sky blows out white, the trees turn to black and only a little of the mid-tones appear as we expected. The photographer has to learn to recognize excessive subject contrast and control it (fill light, reflectors, or just move on without taking that picture). Similarly, the eye/brain adjusts to changes in the color of light. Whether in daylight, tungsten light, etc. a sheet of white paper appears white to our eyes. Not so to film. The photographer has to learn to control white balance with camera settings, filters, or post processing.

Theory to practice
Of course a lot of this photographic theory goes out the window in the real world. But I think it is important to have the theory buried someplace in the back of your mind. I'm the first person to admit that I often don't see the photo until after I take it--sometimes seconds later, sometimes a month later when looking at a set of images again. Much of the process, for me, is subconscious. Something catches my eye and I react. Other photographers are very methodical and go through pre-visualization processes, knowing everything about the image and its final print before clicking the shutter. As in most things artistic, there isn't a right or wrong way. Find the way that works for you and have fun with it!