Behind Every Successful Foreground...

...there is a successful background". I believe this was one on Bob Schwalberg's* basic axioms behind the success of any given photograph. He reminded us that the background is important because it helps to establish a context for the photograph, and in this case prevents the subjects from disappearing into inky blackness.

I am a huge fan of Nikon's iTTL (Intelligent Through The Lens) flash metering, part of what they call the Creative Lighting System. The simplicity of operation has saved my skin many times, and once you get the hang of it, it's pretty simple.

The photo was made at the TheatreWorks costume warehouse. I wanted to make a photograph that gave the viewer a sense of how large the collection of costumes was. My three subjects were co-chairs for an upcoming fundraising event, and I wanted a spontaneous, fun photo of them "trying on" outfits. I chose this particular isle because the far wall wasn't cluttered, and there was enough detail to make the photo visually interesting. I promised to start shooting at 1:45 so that everybody could leave by 2:00, so I did as much as I could before my subjects arrived.


Step 1: Evaluate Ambient Light. I set the camera for Aperture Priority, F 5.6, and ISO 200. I decided to leave the ISO at 200 as a starting point.

The camera chose 1/4 second for my chosen ISO and aperture, too slow to handhold. The light, coming from directly overhead, was a mixture of skylight, fluorescent, and hot incandescents, making for an odd match of color.

Step 2: Foreground Light. For my next shot, I added a light stand mounted, shoot-through Zumbrella with a Nikon speed light. The light stand was put the Zumbrella about eight feet off the ground so it would resemble the top lighting in the warehouse. I also set the shutter speed to 1/60, just fast enough to hand hold. With my speed light set for a +2/3 exposure boost, I got this shot.

Because the Zumbrella was used in the shoot-through mode, the speed light couldn't actually see the Commander speed light mounted in the camera's hot shoe. But the sensor eye did face the wall, and my commander was pointed backwards so light could bounce off the wall where the sensor could see it.

Step 3: Background Lighting. The background was now much too dark, so I added three speed lights to brighten things up. The first was perpendicular to the row of clothing in the background, the second pointed toward the back wall, and the third was a edge light aimed at the clothing. There was also enough light from the camera-mounted commander to reach back and trigger the these speed lihgts, but just barely. Here's a quick test, with a helpful dog in the foreground.

If you look into the background, you can see a hot-spot near the back of the photo. The three speed lights were clustered on a desk in the back of the warehouse, all with their sensor eyes pointing toward me.

After some quick re-arrangement of the set, I started shooting. There wasn't much direction here, just putting the tallest person in the center, and pretty much let them enjoy themselves. I had planned for a more "posed look", but they seemed to be having more fun just joking about their choices. Here again is the final shot.

First a warning, and then some advice. I was lucky that the interior, however dark, had enough reflective surfaces for the commander to "communicate" with all of the remote speed lights. To prevent lens flare, it is better if the background lights do not shine directly into the lens. But having them behind the subjects makes it harder for the Commander to communicate with them. I once mounted a commander on its own 9-foot light stand and connected it the camera via a daisy chain of iTTL cables. The elevated position insured that all the remotes could "see" the commander's pre-flash signals.

In a pinch, the speed lights could have been re-configured to SU-4 mode, a photo-sensative alterntative to iTTL. SU-4 sensor sensativity is much better than that of the iTTL mode, but speed lights so configured must be manually "calibrated" to adjust the light output. For more information, check David Hobby's blog on the subject.

*Bob Schwalberg was a writer for Popular Photography. I could not find any biographical references.

Exposure Fundamentals: Shutter Speed and the Sunny Sixteen Rule

Photo Source: Click here.

Shutter Speed: The last post gave two of the three major adjustments that we have control over, at least to the mechanical and electronic limitations of our cameras and lenses. This typical shutter speed dial from a 35mm film camera clearly shows the shutter speeds expressed as whole numbers. Click here to read the original article.
 

Light Theory: Let us assume that light can be quantified. The sun is radiating energy in specific units called photons. Without getting too technical, the photon is a measure of a fixed quantity of light. Think of it as a droplet of liquid energy, something like a raindrop of light energy. For now, this is all we need to know about light and the relationship to proper exposure.

• On a cloudless day than the photons pass through the atmosphere unencumbered. Our photographic subject reflects a "full value", which we'll address later.
• On an hazy day, many of the photons are reflected back towards the sun, their path blocked by interfering clouds. Depending on the density of the cloud cover, the light on our subject may be reduced by a factor of one-half to one-eighth, or even less.

Exposure Length: Imaging that you have a photon source in the form of a faucet. Exposure length can then be likened to the length of time the photon "faucet" is opened. Taking it to the next level, we know how we can control the amount of this liquid light using the faucet, but how do we know when we have enough?

ISO Redeux: Remember ISO? The last post merely stated the relationship to the values, which was purely mathematical. The higher the ISO value, the more sensitive the medium (film or camera CCD/CMOS sensor). In terms of liquid light, the higher the ISO, the more efficient the film/sensor. So far as the liquid analogy, the higher, more efficient ISO requires a smaller "bucket" to achieve that elusive "proper exposure".

The Sunny Sixteen Rule: Enter the must fundamental exposure photographic truth: The Sunny Sixteen Rule. Here is a reproduction of the "instruction sheet" that accompanied every roll of film sold by Kodak for many, many years. In pre-war American, many casual photographers did not own light meters (built-in meters were many years in the future) followed these guidelines and achieved very close approximations of proper exposure, so long as they stayed outdoors and photographed well after sunrise and well before sunset.

In short, you set you lens aperture to F 16, and set the shutter to the inverse of the film's ISO when photographing in Bright or Hazy Sunlight (see columns 1 and 2).

Photo Source: www.photo.nethttp://photo.net/classic-cameras-forum/00TqHW

Let's extract some additional information, based on what we know about apertures. In this table, you will see that the shutter speed is set to 1/250 of a second. If we examine the five separate exposure situations, we can conclude the following:

Situation	Suggested Aperture	Compensation
Bright or Hazy Sunlight on Bright Sand or Snow	16	0 stops
Bright or Hazy Sun (Distinct Shadows)	11	1 stop
Cloudy Bright (No Shadows)	5.6	3 stops
Heavy Overcast	4	4 stops
Open Shade	4	4 stops

Let's translate these recommendations into some actual values.

Column 1 and 2: Bright or Hazy Sunlight
4	5.6	8	11	16	22	32
1/3200	1/1600	1/800	1/400	1/200	1/100	1/50

This second row shows the necessary "exposure offset" (1 stop of additional exposure) necessary when photographing under a Cloudy Bright environment.

Column 3: Cloudy Bright
4	5.6	8	11	16	22	32
1/1600	1/800	1/400	1/200	1/100	1/50	1/25

This last row shows an exposure offset of 4 stops when photographing in open shade.

Column 4 and 5: Heavy Overcast/Open Shade
4	5.6	8	11	16	22	32
1/200	1/100	1/50	1/25	1/15	1/8	1/4

In all of these tables, each column represent identical exposure values. We can then select the aperture/shutter speed pair that best suits our needs. There are four fundamental rules:

• Choose a large aperture (low numeric value) for less depth of field.
• Choose a small aperture (high numeric value) for more depth of field.
• Choose a fast shutter speed (short duration) when you need to stop action.
• Choose a slow shutter speed (long duration) if you want some blur.

That's a lot to think about, since your built in meter already does nearly all of the heavy lifting. There will be exceptions, as we'll discuss in a later post.

Exposure Fundamentals: ISO Values and Aperture Settings

Margaret Bourke-White (1904 - 1971) on the Chrysler Building, New York.

Photographer:  Oscar Graubner, 1934

Photographs aren’t taken, they are made. I say this because every photo requires some degree of planning, selection of proper tools, and a craftsman’s (or woman’s) execution of the project.  Now occasionally every photographer may need to take a “grab shot”, one without much premeditation.  But even these require some small bit of planning, and the conscious effort to capture a specific small slice of time.

Exposure is at the very heart of the entire process. It is the correct assessment of the amount of existing light, followed by the decision on how we want the camera to render the image. This photographic produce is influenced by our initial selection of three exposure settings: ISO, Lens Aperture and the camera's Shutter Speed. All three factors are related, as we shall see.

ISO Values

ISO used to be called ASA, and was the sensitivity rating for  film. A high ISO value meant that the film was more sensitive to light than a film with a low ISO rating. This roll of Kodachrome has an ISO of 64. Low ASA values were associated with fine detail, while high values tended to add “grain”, irregularities at the image edges that reduced the crispness of the image. Executive summery? Low ASA/ISO, fine detail. High ASA/ISO values degrade detail. Photo: Photographyblog

When shooting, I have four "go to" ISO settings:

• ISO 200 for static subjects, or when used with powerful (or multiple) electronic flashes.
• ISO 400 for general shooting outdoors under natural light, or with a Zumbrella used indoors.
• ISO 800 for indoor bounce flash, or a Zumbrella outdoors.
• ISO 1600 for available light shots made indoors, or long-range bounce flash.

Aperture Settings

Aperture values are mathematical relationships based on the amount of light that can pass through a lens. The aperture is a small “hole” in the lens that opens and closes much like the pupil in the human eye dilates and constricts. As our pupils constrict in response to bright light, so must our lens apertures close (or stop down) to prevent overexposure.

When used to describe a lens, the aperture value is preceded by the letter “F”, a hold-over from the days when the F value (or F-Stop) represented the ratio between the focal length of the lens and the actual diameter of the aperture.

In this series of photographs, you can see the the largest aperture setting on this lens is 0.95 (lower right), which is slightly less that a value of 1.0. At the upper left, a small aperture (F 16).

While we seldom see lenses marked F 0.95 or  F 1.0, 1.4 is relatively common in high performance (and high priced!) fixed focal length lenses. Photo: Nuyoka & Co.

Now this is important.

• Each F value represents a ratio between the focal length of the lens and the lens aperture.
• Low F-Stop Values = High light throughput and shallow depth of field.
• High F-Stop Values = Low light throughput and greater depth of field.

Photo Source: John White's AI Conversions for Nikon Lenses

Here we can see the traditional sequence of aperture values. These values were usually printed on the aperture control ring of manually adjusted lenses of the twentieth century. The short list goes as follows:

1     1.4   2     2.8   4     5.6   8     11    16    22    32    45    64

The aperture ring of this Nikon AI lens has the numbers listed in the reverse sequence. While this particular lens has a maximum aperture (widest setting) of 1.4, many lenses will have an intermediate value such as 1.8 or 3.5. These would fall somewhere between the values I have listed.

Each value on the F-Stop scale represents and increase or decrease in the light transmission by a factor or ½,or 2, depending on whether you go to a smaller aperture (larger F-Number) or a larger aperture (smaller value F-Number).

Current production lens have eliminated the aperture ring altogether. Aperture is set using a command dial on the camera's body. Photo: Nikon Rumors.

Next time: Shutter Speed and the Sunny Sixteen Rule.

Singing In The Rain

November 7, 2010: San Mateo City Council member Robert Ross addresses a rally to raise citizen awareness of the negative impact the California High-Speed Rail Authority’s plan will have on peninsula residents. The protest occurred on Sunday, November 7 in Washington Park across from the Burlingame Train Station.

It occurred to me that two issues could be addressed in today's posting. Normally I limit myself to a discussion of the technical aspects of the image, or what went into making the photograph. But there is a second issue, one that addresses the reason for why the photograph exists in the first place. While we may assume that a picture (or photo) is worth 1000 words, a photo presented in a journalistic venue must tell a story. It is the job of the photographer to highlight those visual elements that add to the viewer's understanding of the event, and minimize (or eliminate) those that detract from the message. This post will start wit the technical backstory for this post and will be followed by some opinions about the photo’s success.

Rain, Rain, Rain: Shooting in the rain happens. I don't like doing it, but you can't change your mind once you're committed to take an assignment. This photo was made early in my "career", and at the time I was anxious to prove myself as a "do-anything, go-anywhere photographer" so long as I could stay within my equipment's comfort level.

When using a shoe mounted speed light, you will need to prevent water from shorting out the hot shoe connection. Nikon makes a water guard, a rubber skirt for the D300 / SB-900 combination that discourages water from entering this junction. I had one, and used it. Luckily for me the rain was light and intermittent, and my parka provided sufficient protection for the camera from the elements. Had it been a real downpour, it would have placed the camera in a plastic bag so that the lens hood protruded from the opening. A little gaffer tape and the camera is safely sealed within. Oh, and be sure to use black gaffer tape. Silver "duct tape" looks so Red Green. And be thankful this is the digital age, which means no film changes, focusing, or fussing with any adjustments. If I couldn’t find a bag big enough for an on-camera speed light, I could have installed a Calumet Wireless Transmitter in the hot shoe and the matching receiver on a hand-held speedlight in its own plastic bag.

Simplicity was the word here.  You really can't get too fancy under situations like this. I wasn’t Joe McNally, after all. This meant that I worked alone with nobody to install my lenses, hold my speedlight, or get me a cup of coffee. I might have been able to mount said receiver / speedlight combination on a monopod, covered with a bag, and achieved an off-camera lighting solution. But when working alone in a crowd, you just don’t have the extra arms and hands to experiment with off-camera lighting solutions.

To make this shot, I used an SB-900 mounted on a D300 with a 12-24 Tokina wide angle lens. It was a straight shot without any compensation for exposure. With the Open Shade white balance preset, the speedlight fill would probably appear a bit warm, but since the faces represented a very small portion of the image area, you probably couldn't tell one way or the other. The flash head was angled high and to the left to decrease the amount of direct light on the sign in the foreground.

Critique: I believe the shot works for the following reasons:

The photo is three dimensional, with details from front through the middle and back to the rear.

• The foreground sign is easy to read and gives the reader a clue as to what is going on.
• The subject plane is composed of three figures, all with faces clearly visible. They are close enough to the camera to be recognizable.
• The background audience lets the viewer know this is some sort of protest.
• The umbrellas held by the two assistants help to frame the main subject. There was nothing I could do about the umbrella that appears at the top right edge of the photo, but the two above the main speaker help the viewer understand why it is there. There wasn’t much more I could do, since I was already at my widest setting, and with a crowd behind me, had no place to go.

I believe that this photo met all the criteria to qualify as proper photo for the venue. It's pretty straight forward, and the intent clear. It was the 13th image I submitted to the paper and was made in the first six months of my "internship". I was just starting to grasp the nuances that contribute to a good photo, and I'm still learning.