Missing Pages - Using a Camera Tutorial

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How to pages not found in any cameras | 1 | Photography

Missing Pages: ISO Setting

Tips for Using Your Camera Creatively by Jon Sienkiewicz

The Missing Pages column is a collection of all of the information that should have been included in your cameras Owners Manualbut somehow got left out. This is a hybrid assortment of short

articles that delivers the know-how you need to derive the maximum enjoymentand creative

expressionfrom your equipment. Its sort of a juiced-up User Guide for creative people who are

not necessarily technical. Each part will teach you how to use one of the camera features or

functions that you previously ignored or left set on Auto. And each will include a Creative Project so

that you can try some scripted experimentation.

We will explain complex technical subject matter a way that everyone can understand. And if you

happen to be a technical expert yourself, were including Nerds Only sidebars just for you. That

way you can dig in deepor just straddle the edgesof the technological stuff. Its your decision.

Installment I: ISO Setting

[also known as Sensitivity Setting or ISO Sensitivity]

Imaging sensors are designed to perform their best when light is at a

certain level. For the convenience of photographers who are accustomed

to understanding the different sensitivity levels of film, manufacturers

(for the most part) build sensors that have roughly the same sensitivity

as a roll of ISO 100 film. In an attempt to keep everything familiar and

understandable, camera makers use a numbering system thats closely

equivalent to the old ISO ratings from film photography. Some even refer

to the relative speeds as ISO, but thats technically not correct.

Nonetheless, for the sake of simplicity well do the same.

This sensitivity can be adjusted to accommodate lower light levels.

Increasing the sensitivity setting to ISO 200, for example, makes the sensor twice as sensitive.

Changing to ISO 400 makes it 4X as sensitive as 100. Increasing the ISO will allow you to shoot in

low light at a shutter speed thats fast enough to prevent camera shake. Thats the primary reason

why one would want to increase the ISO: to make it possible to shoot at a more desirable

combination of f/stop and shutter speed.

Cameras that offer image stabilization lower the shake threshold, so you might be able to shoot at,

say, 1/15th of a second instead of 1/60th. Thats a difference of two stops and the same as increasing

the ISO from 100 to 400. This gives you an idea of how important image stabilization is.

Increasing the ISO and keeping the shutter speed the same will allow you to shoot at a smaller lens

opening (f/stop). That will increase the depth-of-field and increase the zone of sharpness that

extends behind and in front of the point of focus.

Then why not always shoot at ISO 1600?

Adjusting the ISO changes how the camera responds to a given quantity of light. These increases

come at a price, however. As sensitivity increases, so does noise. Noise is the mottled, grainy-

looking texture that appears when you shoot at a high ISO.


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Nobody likes how noise looks, so camera makers use a countermeasure. They process the noisy

digital image signals with noise filters and noise suppression algorithms. This operation occurs in

the signal processing engine. Canon calls their engine DIGIC IV. Panasonic calls theirs VENUS.

Camera makers brand their engines for marketing purposes, and also to track generational

differences (DIGIC IV vs. DIGIC III, for example).

All camera makers handle noise suppression in their own way, so even if two brands of cameras use

the same sensor (which is very common) the results can be quite different because the engines are

different. The noise suppression process often reduces the image sharpness. This bears repeating:

noise suppression is the enemy of sharpness. So we can say that every low-light image is a

compromise between noise and sharpness.

But signal noise is only part of the equation (albeit the biggest part). Light level is also an important

variable. Many folks dont realize this, but shooting at a high ISO like 800 in bright light will yield

better results than shooting at a high ISO in near darkness. Dont misunderstandits always better

to use the lowest ISO that conditions allow. But its important to understand that noise is a product

of high ISO and low light. In some cases its better to shoot at ISO 400 in bright light than ISO 100

in the dark. Thats because noise can increase as a function of time, also. And lower ISO settings

require longer shutter speeds.

What about ISO 50?

Some camerasearly Canon PowerShots, for instancehave ISO 50 settings. Others have ISO 64 or

ISO 80. Settings lower than ISO 100 generally produce the best images a camera can makeat least

as far as noise is concerned.

Leaving your cameras ISO setting on Auto is a mistake. The camera could use a higher setting than

necessary and cause your image to appear grainy or noisy. You dont want that. Besides, you cannot

accurately control the aperture setting or shutter speed setting unless you also control the ISO

sensitivity.

Digital SLR cameras generally perform better than compact cameras at high ISO settings. This is

not always the case, and some compactsthe old Fujifilm Finepix F31 is a notable examplecan

hold their own even when photographing the legendary black cat in a coal bin at midnight. You

can read more about the technical reasons behind this in the Nerd section below.

Creative Project

You dont need any special equipment for this one, just your digital camera. If you happen to have a

lightweight tripod you can expand the project, but thats up to you.

Heres the drill. In normal daylight, photograph a colorful subject at every ISO setting your camera

offers starting at the lowest and working your way up to the highest. Shoot only one shot at each ISO

so that it will be easier to compare the results.

Repeat the same exercise indoors under ambient light that is just sufficient for reading. Dont worry

if the images shot at the lower ISO settings are blurrythats normal. If you want to do the indoor

portion on a tripod, thats fine.


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Depending on your camera, the actual light levels and the subject, you should find that noise

increases as ISO increases. In the outdoor shots, the effect will be less pronounced because there is

more light to saturate the photo sites. The indoor the images may get as shaggy looking as coconut

pancakesor look like a bad example of pointillism.

How does this help you creatively? You must learn to judge light levels and use the ISO setting that

will produce acceptable results. Different camera brand behave differently so its important to

understand how yours performs. Once youve mastered this sense for light levels youll know when

to use flash or a tripod.

Well say this now and doubtlessly repeat it throughout the Missing Pages series: creative

photography is about getting exactly what you wantits not about wanting whatever you get.

Nerds Only

ISO is an abbreviation for International Organization for Standardization. Yes, I know that should

make it IOS instead of ISO (but one must admire a standards organization thats willing to be abit unorthodox). Old timers may refer to the same specification as ASA, the more ethnocentric

American Standards Association. And our European cousins still recall the German counterpart:

DIN (Deutsches Institut fr Normung).

The digital noise that appears when a high ISO sensitivity setting is used is partly the result of

physical measurement between photo sites (pixels) that engineers call pitch. Pixels that are

packed very densely together have a very small pitch and are noisier.

At a given megapixel level, small imagers have greater density, smaller pitch and therefore more

noise. The image sensor (usually a CCD but sometimes CMOS) is measured diagonally and the

dimension is expressed as a fraction. To confuse you, the fraction contains a decimal in the

denominator. A CCD that is 1/2.5 inches is actually equal to 1 divided by 2.5 inches, or 0.40 inches. A CCD thats 1/1.6 (which may seem smaller) is 0.625 andall else being equalwill produce

images with less noise.

To really confuse the issue, many people refer to the ISO setting as the speed. This is another

throwback to 35mm photography where we often talked about film speed. Its best to avoid this

nomenclature since speed is already overused to describe large f/stops (fast, high-speed f1.2

lenses) and shutter speed. A better term for sensitivity adjustment, scientifically speaking, would

be gain. Audiophiles and people who dig shortwave radios are already familiar with this

expression as the technical term for an amplifiers output/input magnitude ratio.

You can remove most of the noise from a digital image during post processing by using NIK

Softwares Dfine or other product. Adobe Photoshop CS4 also has some potent noise-busting tools.But like poison ivy and hangovers, its always better to avoid noise than to cure it.


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Installment II: Program AE

[slightly more extensive than the auto/green mode]

Definition: an auto exposure system in which the camera achieves correct exposure by selecting the shutter

speed and aperture (f/stop) from a predetermined table.

To understand Program AE you must understand the fundamentals of exposure. The amount of light that

reaches the imaging sensor is determined by two physical factors: the size of the lens opening (aperture, or

f/stop) and the length of time the light is allowed to travel through that opening (the shutter speed). The

sensor doesnt care whether you use a small aperture for a long time or a large aperture for a short time, just

so long as the net result is that the same amount of light reaches it.

In other words, its possible to achieve exactly the same precisely correct exposure using different

combinations of apertures and shutter speeds. For example, you can shoot at f/2 at 1/500 second, or f/8 at

1/60 and either combination will yield correct exposure. However, which combination you choose can have a

profound effect on your image.

Please take a look at the accompanying graph. The red line shows Equivalent Exposure. Shooting at f/16 for

1/8 second is equivalent to f/5.6 at 1/60. The green line is called a Program Slope. It shows how a typical

Program AE system might automatically adjust shutter speed and f/stop settings in reaction to differing light

levels. With most cameras, the steps are seamless and infinitely variable but follow the same slopewhich

means you may shoot at 1/131 of a second at f/4, for instance. In this example, Program AE forces the camera

to use a high shutter speed as much as possible, and never drops below 1/60 of a second.


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Program AE makes rational choices for you. In general, Program AE tries to shoot at a relatively fast shutter speed

because it operates under the normally correct theory that most people have a hard time holding cameras still at

slower speeds. Program AE delivers correct exposure and good results most of the time. But when you use this

mode the camera is making two critical decisions for you, and whenever the camera is doing the decision making,

you are losing creative control.

Remember, your creative ambition is to get what you want, not merely want what you get.

Look at the image of the young girl holding a snail. The hand is in focus but the

girls face is blurred. The image was not shot in Program AE. It was shot at wide

open at f/2.8 to obscure the human and emphasize the creature.

If you want to control depth-of-field you must control the aperture. Small

apertures produce greater depth-of-field than large ones (all else

being equal). If you want to control subject motion (e.g., freeze action at a

sporting event) you must have control over the shutter speed. Slow speeds allow

subject blur whereas fast shutter speeds do not.

Camera manufacturers are aware that not every program setting meets the needs of the shooting

environment, photographers creative impulse and subjects special requirements. So they have provided two

effective ways to provide photographers with creative control. The first is called Program Shift.


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Installment III: Aperture & Shutter Priority

Definition: exposure modes that provide more control than Program AE but less

than Manual mode.

Shutter Priority is an auto exposure system in which the camera achieves correct exposure by selecting the

aperture after the user has selected the shutter speed.

Conversely, Aperture Priority is an auto exposure system in which the camera achieves correct exposure by

selecting the shutter speed after the user has selected the aperture.

Each system has its own set of distinct advantages and disadvantages. But to fully understand Aperture

Priority and Shutter Priority you must understand the fundamentals of exposure. Please refer to the preceding

segment (Program AE) if you need a quick review.

Todays digital SLR cameras (and a few high-end compact models like the Canon PowerShot G10) offer both

Aperture Priority and Shutter Priority automatic modes in addition to Program AE. There was a time,

however, back during the era of Canon AE-1 popularity, that 35mm film cameras offered one autoexposure

system or the other. And each method had its own passionate group of proponentsand detractors.

The Canon (Shutter Priority) crowd argued that it was better to set the cameras shutter speed and allow the

camera to respond by setting the appropriate f/stop. They claimedand rightfully sothat by choosing a fast

shutter speed it was easier to control camera shake and to stop subject movement. Minolta, Nikon and Pentax

(Aperture Priority) followers insisted that setting the aperture was the preferred procedure because it gave the

user full control over the depth-of-field and allowed the user to preselect the optimum aperture for any lens.

Both sides were correct, of course, each in their own way. In retrospect, this issue was one of the most

polarizing disputes among camera enthusiasts, no pun intended. One might have expected a different

outcome to this hotly debated argument, but the final result was the development of Program cameras that set

BOTH the shutter speed and aperture, essentially leaving the user out of the equation almost entirely. Better

cameras offered all three: A mode, S mode and Program AE. The Minolta XD-11, which debuted in 1977, was

the first camera that could claim Dual Mode by offering both A and S modes.

Aperture Priority

Sometimes called Aperture Preferred because that term more accurately

describes whats in the users mind when they make decisions about the

camera settings; and labeled Av (Aperture Value) by Canon and others;

Aperture Priority allows the user to control depth-of-field (that zone of

sharpness that extends in front of and behind the actual point of focus).

Because its often indicated by an A on the control dial, some people

mistake the setting for Automatic.


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Having control over the DOF is very important in more situations than not. When shooting portraits, for

example, its desirable to force the background to blur by using a large aperture. This effect separates the

subject from whats behind them and gives the appearance of accentuated sharpness. It also allows you to

deemphasize distracting backgrounds by making them fuzzy and indistinguishable. Controlling DOF is

similarly important when you want a larger zone in focus (greater DOF), such as when shooting close-ups or

certain landscape scenes.

Controlling the aperture allows you to select the sweet f/stop that delivers the sharpest images. There are

rare exceptions, but most lenses perform better when stopped down two or three f/stops. A 50mm f/1.4

Nikkor, for example, will yield better results at f/4 than it will at f/1.4. And contrary to intuitive logic, using an

f/stop like f/22 thats quite small introduces diffraction, which robs the image of sharpness, despite the

extended depth-of-field.

Shutter Priority

Known as Tv to Canon (for Time Value), theres a lot to be said about

the efficacy of this systemparticularly in light of the fact that all camera

makers recognize the detrimental effects of camera shake and are moving

toward some sort of Image Stabilization to reduce it.

In S Mode, you set the shutter speed and the camera does the rest. Well,

not quite. The argument that the Aperture Preferred crowd often made

was this: if you set a shutter speed thats too high (1/250s indoors, for example) youre likely to get no picture

at all. As a countermeasure, many cameras will warn you and then shift to a slower speed when its impossible

to achieve correct exposure at the speed you selected. And some will even adjust ISO (although thats really a

case of relinquishing control over the final outcome to the camera and hoping for the best).

Controlling the shutter speed means you can help prevent camera shake and more importantly, freeze subject

movement. If youre shooting a track and field event, for example, or a little league game, you can use a very

fast shutter speed to stop motion.

This theory works well indoors, too. For any given lens you should know the minimum shutter speed you can

successfully handhold without shake. I call this the SBA or Shake Begins At

shutter speed (ungrammatical but easy to remember). With a 50mm lens

equivalent, for example, most people can shoot at 1/60 of a sec or so. General rule

of thumb is 1 over the focal length as in the fraction 1/focal length. So the

equivalent to a 135mm lens would require a shutter speed of about 1/125 or higher

for safe, jiggle-free results. (Remember that this old rule came to be before digital,

so you must account for the lens multiplier when calculating.) In Shutter Priority

you can set the camera at your SBA and blaze away with little fear of camera


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shake.

Creative Project

Do you have a favorite lens? One that always seems to yield the sharpest images? With that go-to lens in mind,

what range of apertures delivers the absolute best performance? You really need to know. For the sake of

having an example, lets say youre a Nikon D90 shooter and your favorite lens is the 50mm f/1.4. (Not a bad

choice, by the way, in that it translates to a 75mm f/1.4 on your DSLR, which gives you a nearly perfect

portrait lens).

Exercise 1

Get out the tripod, find a subject with detailed texture, and set up ten to fifteen feet away. If you cant think of

anything better, aim your camera at a painting thats hanging on a neutral wall. Shift your camera into

Aperture Priority mode and begin shooting at the largest f/stop, working your way down to the smallest. How

do the images in the series compare in terms of sharpness?

You may find that your results resemble these: Wide open at f/1.4 you get good results, but stopped down to

f/4 or f/4.5 (the half stop between f/4 and f/5.6) the lens really shines. Sharpness remains until around f/16

where diffraction takes over and the resultswhile still acceptableare not as biting-sharp as at f/5.6 or f/8.

Exercise 2

For the second exercise, position a human subject five feet from the painting and ten feet from the camera.

Repeat the exercise above, keeping the camera focused on the human. This time when you examine the

results, closely look at how the subject becomes more separated from the background as depth-of-field

decreases.

Exercise 3

Dont freeze the action all of the time. Movement can add dramatic emphasis to the dynamic flow of a river,

for example. Youll need the tripod again. If you dont have a gushing waterfall handy, moving traffic

(especially at night), frenetic musicians (especially during the wee hours) or typical preschoolers (after a

sugary snack) will provide enough subject movement to make this test worthwhile. In S mode, select a very

slow shutter speedone-half second or longer, unless its so bright that youll overexpose. Make sequential

exposures at progressively faster speeds until you reach the speed that completely stops all subject movement.

Then compare the results in your favorite image editor.

What about M mode? M stands for Manual, of course. Thats a great Creative Project but thats for another

episode!

For Nerds Only

Whats Pi got to do with f/stops? And why is f/2 twice as big as f/2.8 and four times larger than f/4? Shouldnt

bigger numbers mean bigger apertures?


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Shutter speeds are pretty easy to understand. 1/100 of a second is obviously half as long as 1/50 of a second.

But when it comes to f/stops nothing seems to make sense. Thats because an f/stop is a fraction. Its the ratio

between the lenss focal length and the diameter of the active aperture. For example, a 50mm lens that is set at

f/2 has an aperture that is 25mm in diameter. Similarly, a 50mm lens that is set at an aperture that is 8.9mm

in diameter is said to be set at f/5.6 (i.e., 50/8.9 = 5.6).

Remember high school algebra? Im sure many photo.net readers will want to jump in here and untangle my

amateur math, but heres what I remember. To calculate the area of a circle one multiplies the radius times the

radius times pi. Or in other words, the radius squared multiplied by the constant 3.14159.

If youre still with me, look at the following table.

For a 50mm lens:

So, its (fairly) easy to see why f/2 is about twice as large as f/2.8. The area is about twice as large. As we go

down the scale, each increment of one f/stop equals a 2X change in exposure because the area becomes half as

large. That is to say, each subsequent f/stop is one-half as large as the preceding f/stop. Half of a half is a

quarter, so the difference between f/4 and f/8 is two stops, or 4X.

Why use such a goofy system? Because it can be applied to a lens of any focal length. For the purposes of

calculating exposure, a 135mm lens set at f/5.6 delivers exactly the same amount of light as a 300mm lens at

f/5.6. Were it not so, it would be virtually impossible to base camera exposure settings on an external

handheld light meter.


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Installment IV: White Balance

Definition: Determination of the exact color adjustment necessary for a digitalcamera to render a pure white object so that it appears pure white in the

captured image.The assumption is that if white is rendered correctly, all of the other colors will be also. Conversely, if white

has a color cast, it doesnt matter if the other colors are rightthe picture will look wrong.

Lo, the human brain! Among its many wonderful talents, your brain has the ability to restore proper

coloration to most of the physical objects your eyes see. If youve ever shot daylight-balanced 35mm film

under normal tungsten incandescent light you doubtlessly produced images that were brownish-reddish

even though the scene looked normal when you viewed it firsthand. Psychologists have told me the brain

makes corrections to the signals it receives from the eyes because thats way the brain copes with altered

reality. Your brain replaced the blue coloration that was missing from the scene because it needed to keep

things normal-looking.

This ability may be rooted in our evolution from animals that needed to be able to detect subtle color

differences in plants so that they could determine which were edible, ripe or spoiled regardless of the time of

day or lighting conditions. Thats just my guess, but Im sticking with it since most human characteristics are

one way or another related to survival.

Cameras need help to make these adjustments. Yes, many have Auto White Balance settings. But like many of

the other Auto settings, the results are usually pretty close but rarely dead-on accurate. Cameras also offer

Preset and Custom settings. More on those later.

First, lets dispel the misconception that you can easily correct for White Balance miscalculations by using

Photoshop. Experts can salvage some poorly balanced images and many people can make the images look

better, but theres no substitute for getting the white balance set correctly in the first place.

White Balance is not difficult to do or hard to understand. In fact, at the most basic level, all you really need to

consider are three colors: our old friends R, G and B.

The spectrum of visible light ranges from R (red) to B (blue), or more correctly, from near-infrared to near-

ultraviolet. Light color is determined by its wavelength, so it can be objectively measured, filtered and altered.

White is a mixture of all colors (even though that may sound counterintuitive). Pure white objects reflect all

incident light in the 400-700nm (nanometer) range.

Color is objectively identified by its temperature, which is expressed in degrees Kelvin. A color temperature

meter will tell you that noon daylight is around 5,500 degrees and that normal room light generate by a GE

Softwhite tungsten light bulb is closer to 2,900 degrees. On a cloudy day, the color temp might be in the 6,600

to 8,800 range. We call reddish light in the 3,000 degree range warm and bluish light in the higher 7,000

degree area cool even though the numerical value of the cooler temperature is higher. Remember it this way:


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Creative Project

Sunsets and sunrises are dramatically influenced by shifts in white balance.

Remember that when the sun sets, we still see its red, glowing orb even after it

has physically slipped below the horizon. Thats because the long red wavelengths

are diffractingessentially bending over the horizon linelong after the star

itself has disappeared. All of that light is red. A dissimilar thing happens at

sunrise. For creative exercise, set your camera on a tripod, face the sunrise, and

make exposures using every available White Balance option. Work quickly,

because the color temperature of the light will change as you watch. If your

camera allows Custom (Manual Preset) use that setting first to establish a

baseline. Wait until sunset and repeat. This will usually require turning to face the opposite direction.

Try to use the settings in the order that they appear on the menu or dial, or write down the order that you usethem. Lacking that, use the browser software that came with your camera to review the images. It will allow

you to read the Metadata where youll find a record of the White Balance setting associated with each image.

For Nerds Only

If you feel mired down the in the details, theres good reason for it. When were talking color temperature and

white balance, we use the word mired as the contracted form of the expression micro reciprocal degree.

Changes in color temp have a much stronger effect at the lower temperature ranges than they do at the higher.

For example, a 1,000 degree shift from 2,900 has substantially more impact than a similar adjustment at

10,000 degrees. So color scientists devised a system to balance things out. The system is based on this

formula: multiply the inverse of the color temperature by 10 to the exponent 6 (10 6). You get the same result

by dividing 1,000,000 by the color temperature as measured in degrees Kelvin. Special color balancing filters

called decamired filters are used to make adjustments to white balance based on these calculations.


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Installment V: Depth of Field

Definition: The area in front of and behind the point of focus that also appears to besharp.

Youve seen the classic portrait that depicts a smiling face in sharp focus floating over a blurred and obscured

background, as in the photo below. The subject appears to pop right off the page. And youve seen hundreds of

shots of landscapes where the animals in the foreground are as sharp and clear as the mountains behind them.

How can you control exactly whats in focus and whats notparticularly with an autofocus camera?

The phenomenon at work here is called Depth of Field (DOF). Because its

predictable, reproducible and measurable we can use it to our best

advantage. And since its been studied by scientists and optical engineers

for centuries, we know a lot about it.

DOF increases as the diameter of the aperture decreases; in

other words, a smaller f/stop (like f/16) generates greater DOF

than a larger f/stop (like f/2.8). Sometimes people confuse this with sharpness but the two

are quite different. In fact, using a very small aperture can rob you of sharpness. You can learn more about

that by reading the Nerds Onlysection below.

One way to control DOF is by using the right aperture, the aperture that delivers the amount of DOF

that youre after. Shooting in Program or Auto Exposure mode surrenders control over the f/stop, so your

camera must be set on Aperture Priority or Manual if you wish to control DOF. Some lenses have a Depth of

Field scale printed on the barrel. It looks like a symmetrical set of hash marks that delineate the range of focus

when aligned with the aperture thats being used and the distance from the subject.

This is a very reliable way of determining DOF. Unfortunately, it is

accurate without being precise. The increments are simply too inexact. As

you can see in the image above, this particular scale skips from 1 meter to

1.5 meters to 3 meters to infinity. And you wont find a scale on a zoom

lens since the focal length is literally a moving target.

Optical engineers have created DOF charts for many different lenses.

Many high quality lenses include these charts in the owners manual. DOF can be calculated mathematically

using the circle of confusion for a given lens as one of the variables. The term circle of confusion describes a

spot of light that is slightly out of focus when a lens is focused on a given point. You do not need to know

anything about circle of confusion to control DOF.

Some digital SLR cameras have a DOF preview button. Even if your camera does have one, dont trust it 100%.

The DOF that your eye perceives when looking through the viewfinder differs from what the camera sees, even


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when the lens is stopped-down to the shooting aperture. Its a close approximation, but not identical. Use a

DOF chart or the scale described above.

Constants

Wide angle lenses produce more DOF than telephoto lenses (assuming that film format or sensor

size is the same). Some will argue that if you crop a WA image to match the field-of-view of a telephoto lens

the DOF will commensurately diminish. So what? The point remains: put a wide-angle lens on your camera

and youll enjoy more Depth of Field.

Depth of Field always extends 1/3 in front of and 2/3s behind the point of focus. No matter

whether the DOF is deep or shallow, it always follows this formula. This fact becomes more valuable when you

do macro photography.

Depth of Field decreases as the distance between the subject and film

plane decreases. You have VERY little DOF to work with when doing

macro photography and are focused just a couple centimeters away, but

you have extreme DOF when focused at a point near infinity.

All lenses have a Hyperfocal Distance for a given f/stop. If, for example, the Hyperfocal Distance happens to

be 16 feet for a particular lens/aperture combination, everything from one-half that distance (8 feet) to

infinity appears to be in focus. If your lens has a DOF scale as described above, line up the infinity symbol

with the f/stop you are using and you have just set your lens to its Hyperfocal Distance for that f/stop.

Depth of Field sounds like a good thing and usually it isbut not always. If you want to produce dramatic

portraits youll want to limit DOF, as in the image at the top of this story. By limiting DOF you can make a lens

appear sharper. Can you guess why?

Creative Project

Boke (sometimes spelled bokeh) is pronounced bow as in beau plus keh rhyming with the first e in

edible. In Japanese is means fuzzy and in photography its used to describe the parts of a photograph that

are not in focus. Boke can also be used to describe people with fuzzy behavior, but thats another story.

Anyway, some lenses are optimized to produce attractive boke. Your assignment is to explore boke and how it

relates to DOF.

Youll need a lens with a fairly fast aperture: f/3.5 or faster. Position a human subject at least two meters from

a background thats filled with bright colors and small detail (for example, the wall of snazzy-looking cereal

boxes one sees at a grocery store).

Focus on your subject from a distance that allows their shape to occupy about 50% of the frame and shoot

with your lens wide open (largest aperture) in Manual or Aperture Priority. Repeat these steps, but this time

stop the lens down three full stops. Now compare how the out-of-focus backgrounds are rendered.


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How to pages not found in any cameras | 17| Photography

Try the same experiment outdoors using a background of flowers or trees, preferably with a bit of backlight

filtering through (so that you can blur a few point sources and highlights).

For Nerds Only

Nearly every aspect of photography involves achieving a balance between competing forces. DOF competes

with sharpness and diffraction is the culprit.

Diffraction occurs when light encounters an obstacle that it cannot penetrate. Light travels in waves that are

parallel when unobstructed. When light waves pass through an aperture they begin to diverge and interfere

with one another. The smaller the opening, the greater the interference. Light waves that are traveling

divergent paths are, by definition, traveling different distances and becoming out-of-phase overall. So at some

point, an aperture that is too small will cause the photo to be unsharp, even though it will have tremendous

Depth of Field. To get the most from your lenses you should know the sweet aperture, the f/stop that

delivers the best image with the fewest aberrations. And you should know at what point diffraction begins to

rob your lens of sharpness.


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how your camera handles exposure bracketing. Some cameras randomly change the f/stop or shutter speed

and you lose control over those critical settings.

The Nikon D5000, for example, adjusts the exposure depending on the exposure mode you select. If you

bracket while shooting in Aperture Priority, it changes the shutter speed. Likewise, in Shutter Priority it varies

the aperture setting. In Program mode it slides up and down the program slope and changes either or both.

And if you have ISO sensitivity set to Auto, the D5000 will automatically adjust that too for optimum

exposure when the limits of the camera exposure system are exceeded (page 103 of the Nikon D5000 Users

Manual).

The second most popular parameter to bracket is White Balance. If youve ever been disappointed by an

otherwise perfect shot thats too green (under fluorescent light) or too blue (outdoors) you can easily

understand why. Its true that in many cases you can correct the color in Photoshop, but its valuable to have a

good clean white to start with and bracketing the White Balance setting is one way to secure that. The better

solution, of course, is to shoot RAW and make your white balance adjustments when you decode the file. But

not every camera records in RAW file format and not every photographer uses RAW every time. That explains

why even high-end RAW capture machines like the Canon EOS 5D Mark II allow you to Autobracket White

Balance.

In reality, the camera is simply adding a finite amount of color bias in one of four directions: amber, blue,

green or magenta. Some cameras offer only amber/blue options. Varying amber and blue allow you to

improve images captured under regular old tungsten house lights as well as daylight. The green and magenta

settings are primarily for certain types of fluorescent tubes. With most cameras that offer Autobracketing of

White Balance, you can set the amount of color bias thats applied. When set on White Balance Autobracket,

the Nikon D5000 captures one image and processes it three ways to alter the color. You can add one, two or

three units of blue and amber plus the normal color rendition.

White Balance Autobracketingalone or in conjunction with manually

applied variationsis a powerful tool and a great, creative way to explore a

scene. And your camera may have another unique feature that can be

bracketed. For example, the Nikon D90 and D5000 cameras allow you to

bracket Active D-Lighting effect. Active D-Lighting is a feature that

essentially extends dynamic range by preserving details in highlight areas and in shadows. Dig out that

Owners Manual and check it out.

One word of caution: make sure the subject doesnt move between shots when youre doing any sort of

bracketing. That seems like common sense, but youd be surprised how many people try to bracket a street

scene, flower thats blowing in the wind or rapidly changing sunset and wonder why the sequence appears

abnormal. If your camera can capture three or four frames per second, the results should be finejust make


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sure you have the drive mode set accordingly. If you are slowly or manually bracketing, be wary of changes in

the scene.


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Creative Project

Bracketing exposureeither automatically or manuallyis too easy to be a Creative Project, but you should

run through the steps enough times that youre comfortable shifting into bracket mode when necessary. And

you might be surprised by the difference a 1/3 or 1/2 stop makes, particularly in scenes that are High Key

(tones ranging from middle gray to white) and Low Key (tones ranging from middle gray to black). Most

important, study the metadata of bracketed images to learn how your camera adjusted itself. As mentioned

above, the ideal way is to keep either the f/stop or shutter speed constant while varying the other.

If your camera offers automatic White Balance bracketing, select a scene

or subject that contains something thats pure white. Purists will want to

experiment with scenes that have two or all three of the primary colors as well. I find that commercial signs,

the sort that hang above business storefronts, often fill the bill perfectly. If you live near an area that has a

carnival-type atmospherea boardwalk on the Jersey shore, for example, or something akin to the equallyflush (although temporary) Taste of Milwaukee celebrationyoull have no trouble finding white signs with

colorful lettering. The assignment is to explore the White Balance Autobracket feature at different times of

day: (ideally) dawn, midday and dusk. Short of that, midday and either dawn or dusk.

For Nerds Only

On May 23, 2001, Minolta Corporation officially introduced the worlds first 5-megapixel digital camera, the

Minolta DiMAGE 7. This model had been exhibitedunder glassat the Photo Marketing Association trade

show the previous February, and in fact won a prestigious DIMA Award from that organization. One of the

unique features of this marvel was Autobracketing of four different parameters.

The DiMAGE 7, fondly remembered by many because of its insatiable

appetite for double-A batteries, featured Autobracketing of Auto

Exposure, Subject Contrast, Color Saturation and Filter Effect. The Filter

Effect option was especially cool. In the right hands, the DiMAGE 7 was a

powerful tool that offered high resolution, outstanding image quality, a

sharp 7X manual zoom, 28mm wide angle coverage and other leading

features. In many ways it was ahead of its time. It also had another unique

featureone that may incite you to buy one secondhand.

The DiMAGE 7 lacks an IR-cutoff filter. That means IR (Infrared Light) passes freely to the CCD. Used with a

deep red IR filter, you can capture some extraordinary IR images. To the right is an image captured with a

DiMAGE 7 by noted photographer and infrared expert Steve Rosenbaum. Well learn more about IR in future

segments of Missing Pages.


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Installment VII: Megapixels

Definition: Citing megapixels (MP) is a popular shorthand way to expressthe resolution of a digital camera in terms of how many millions of

individual pixels (picture elements) are present in the image at time ofcapture.

Note the significance of the phrase ...at time of capture in the definition above. Resolution can be occultly

increased through interpolation, a process that analyzes actual data and makes intelligent guesses to increase

the quantity of information. The number of physical pixels doesnt change. The cameras signal processing

engine fills in the blanks based on complex mathematical algorithms.

After an image is captured you can change the number of pixels that it contains, sometimes without even

realizing it. When we Resample an image we change its pixel dimensions. Upsampling involves adding pixels,

while Downsampling requires discarding pixels. Both procedures degrade image quality, sometime

significantly. People often do this indiscriminately when resizing images to print them. Below is an extreme

example of an image thats been degraded by Upsampling.

Resolution has a horizontal

component and a vertical

component. An image that is 1200

pixels tall by 1800 pixels wide

contains 12001800 or 2,160,000

pixels. Thats about 2-megapixel.

One megapixel is not actually one million, although its close. 1MP = 10241024 = 1,048,576, so we accept

with nearly 5% inaccuracy because, well, it really doesnt matter just as long as everyone counts them and

labels them the same way.

Incidentally, an image that measures 12001800 is said to have an Aspect Ratio of 2:3, which is the same as a

46 inch print.

Many camera specifications show one number for Total Pixels and a lower number for Effective Pixels. The

first, larger number indicates how many pixels can be counted on the entire surface area of the CCD or CMOS

imager, including the edges that are not used. The second number is the only one thats meaningful, as it

indicates how many are actually recording data.

How many megapixels do you need?

How many megapixels do you really need? It all depends on what you

want to do with the image. Unfortunately, digital cameras are lumped into

categories based on the number of megapixels they can capture, and

uninformed consumers make erroneous conclusions about image quality


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based on that single label. Having more pixels does not always mean better images. These images were shot

with a humble 3-megapixel camera.

Having more megapixels can offer some distinct advantages, however.

Higher resolution images produce larger prints without loss of quality.

If you make 1319 inch prints, for example, you need all the resolution

you can get. The second advantage, one thats all too often overlooked,

is that you can crop smaller portions of a high-res image and still retain

high quality.

On the other hand, if you are producing images for a website, or mostly

print 810 or smaller, a nice 6-to-10 megapixel camera will serve you fine. Like many photographers,

however, you may cling to the notion that someday youll want to turn

your images into gigantic poster-sized prints. In that case, shoot large

RAW images now and you wont regret it later that is, unless you runout of hard drive space. Read on.

High resolution comes at a high price. More megapixels mean larger files.

Large files make for longer download times and can really fill up a

memory card fast. Ditto your hard drive and backup externals. Its not

unmanageable, but you should be prepared. Think in terms of terabyte

drives in your RAID configuration and youll be okay.

Do not confuse Resolution with Compression.

The Compression variable is often shown on the cameras menu under the heading Quality. Camera makers

essentially hide the squeeze factor by giving the various compression ratio levels clever aliases like Fine,

Standard or Extra Fine. In truth, the compression ratio varies from as much as 20:1 to as little as 2:1 (plus, of

course, uncompressed). It should be easy to understand that the more you squeeze the more you lose in terms

of data. Some folks turn up the compression while keeping the resolution at the max setting to save file space.

Not good. Its far better to keep the compression as the lowest setting and reduce the number of megapixels.

More megapixels can in fact be a very bad thing if the additional pixels are crowded onto the same size CCD.

In other words, some 6-megapixel image sensors can outperform 10-megapixel image sensors with the same

physical dimensions because the 10MP sensor obviously has less space between the pixels. This space is called

pitch and as it decreases the noise level increases. Increasing the number of pixels means increasing the

pixel density, which in turn almost always means noisier images.

There are notable exceptions, and some camera makers have devised ingenious ways to diminish (if not

entirely neutralize) noise. But there is a downside to aggressive noise reduction, too: less sharpness. Few


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DSLR cameras and darn few compacts achieve an acceptable compromise. Thats another reason why its

important for the creative photographer to understand how the Resolution, Compression and Noise

Reduction settings interrelate on their particular camera.

Its very encouraging that the latest crop of popular compact cameras that are aimed at enthusiasts (Canon

PowerShotS90, Panasonic Lumix DMC-LX3, Fujifilm F70-EXR for example) have put the emphasis on image

quality and noise reduction instead of sheer marketable megapixel power. Camera manufacturers do listen to

their customers who demand high quality images, not inflated numerical specifications.

Creative Assignment

Every digital camera Ive ever seen allows the user to dial down the resolution. The Canon EOS 5D Mk II, for

example, offers setting of 21.0, 11.1 and 5.2 megapixels when shooting JPEG and similar settings for

RAW+JPEG. The Creative Assignment for this installment has three parts.

First, with your camera on a tripod, set the highest resolution and lowest compression ratio that your camera

offers and shoot a colorful but stationary subject. Do this in bright light so that image noise does not become

an issue. Repeat this process for every resolution setting your camera offers, but keep the compression ratio

the same throughout. Since different cameras use different nomenclature for Resolution and Compression

youll have to check the Owners Manual. If youre shooting a Nikon D5000, for instance, youll set Image Size

sequentially at Large (42882848), Medium (32162136) and Small (21441424) to get 12.2, 6.8 and 3.0

megapixel images.

Next, repeat the above, but set the compression ratio to the highest level (i.e., most compression). Again using

the Nikon D5000 as an example, you have the option to set the Image Quality JPEG Fine for 1:4 compression,

JPEG Normal for 1:8 and JPEG Basic for 1:16. For this exercise, use the 1:16 setting.

The third step is done with Photoshop (or Aperture, Lightroom or even the browser that came with your

camera). Open two images that were shot at the same resolution setting but at the extremely different

compression settings. Then, with both images open, zoom 100% (Actual Pixels) and critically examine the

differences. If you fail to see any difference, make an appointment with a qualified ophthalmologist. At the

very least you can expect to see the high resolution/low compression appear much better than the low

resolution/high compression. How much better depends on your camera and, to some extent, the subject. A

shaggy dog looks pretty good no matter what setting you use, but a persons facefull of details and skin

texturewill change dramatically based on how you have these two parameters set.

Bonus Assignment: borrow (or buy secondhand) a digital camera that

has a VGA (640480) resolution option. Many current compact cameras,

including the Canon PowerShot SD1200 IS, offer VGA resolution as an

option. Confirm that the camera is set at the low-res setting and carry it


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with you the next time you go out to photograph. You can use your real camera, too, but be sure to shoot

every interesting subject at VGA. When you download and examine the images you will be amazed how good

they can beprovided you dont try to make them bigger than they should be.


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For Nerds Only

The first breakthrough 5-megapixel camera, based on a Sony CCD, was the Minolta DiMAGE 7, shown at the

PMA Show in February of 2001 and introduced to the media at bi-coastal press conferences on May 23, 2001.

Precisely 90 days later, Sony introduced their own 5-megapixel camera, the Cyber-shot DSC-F707. Ironically,

when Minolta abandoned the digital camera market after being acquired by Konica, it was Sony who

purchased all of the Minolta digital camera patents, technology and intellectual property (and hired quite a

few Minolta engineers, as well).

Got film? Dedicated film scanners in the 4000 dpi range can create 40006000 pixel digital images of

extraordinarily high quality. If youre one of us who began taking pictures long before the digital age, consider

a film scanner to resuscitate your collection of negatives and slides. Dont settle for a multi-function flatbed

scanner that also does film part time. If you want the best quality, buy a film scanner that is optimized for

scanning film.


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How to pages not found in any cameras | 27| Photography

Installment VIII: Flash Modes

Definition: Preset combination of exposure settings that determine whether or not a built-in

flash will fire and if it does, how it will synchronize with the cameras shutter mechanism and

other camera parameters.

The little flash thats built into or pops up from your camera is simple, right? When its too dark it fires, and

when its bright it keeps its head down and minds its own business.

Wrong.

The flash itself is a marvelously simple invention. It consists of a flash tube, which is just a bulb thats capable

of becoming very bright for a very brief period of time (as short as 1/50,000th of a second), a battery and a

capacitor to store the energy needed to make the bulb get bright. The term recycle time refers to how long it

takes for the capacitor to form (i.e., accumulate enough energy from the battery so that it can intensely

power the flash again). The flash synch speed is the maximum shutter speed that a camera can set when the

flash is active. This differs widely from camera to camera. Some cameras have a hot shoe, which provides

both a secure attachment point and an electrical contact for synchronization.

An Electronic Flash Unit (as the shoe-mounted version is known in the trade) as well as your cameras built-in

flash is remarkable because in many ways a flash is like a jar full of lighting (the spark, not the beverage).

Correct exposure depends on controlling it, and thats not an easy thing to do. The intensity of the flash is

controlled by adjusting the duration. But its not as easy as is sounds. So camera manufacturers, over the

years, have contrived ways to tame the lighting so that youll get more pleasant results. This collection of

controls is called Flash Modes.

Forced Off

Okay, it may seem logical to presume that when the flash is not on its off but thats a faulty assumption.

The Off or Forced Off (Panasonic calls it Suppressed) Mode means that the flash cannot fire. This is an

important distinction because many (if not most) of todays cameras will turn the flash on automatically when

needed, even if you are not particularly expecting it.

Auto Flash

Ahheres the culprit to blame for the mayhem in the paragraph above. In the Auto

Flash mode the flash remains dormant until the camera decides its time to put a

little light on the subject, at which point it signals the flash to move into position and

commence firing.

Forced On

As the name implies, in this mode the flash will fire whether it wants to or not. I often

tell beginners to think backwards and turn their flash ON outside and OFF indoors.


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That exposes them to the benefits of both Fill-in Flash outdoors and Available Light inside. Forcing the flash

to fire outside, even when theres plenty of light, will brighten colors and wash away shadows, especially those

that make human faces look more like masks. Forced On flash also saves your bacon when shooting a backlit

subject.

Fill-in Flash

Not all (in fact, not many) cameras have this feature as a separate mode; instead its usually incorporated into

the Forced On mode. But its worth mentioning because of the concept behind it. The primary light source is

ambient lightthe flash merely fills in the shadows.

Red-eye Reduction

Aside from zombies, glowing red eyes are never flattering. Light from the flash

reflects directly off the retina at the back of the eyeball, and if the flash source is too

close to the lens axis, the result is a lifeless red blaze. As a countermeasure, cameras

use various techniques to cause the pupil to contract, thus reducing the problem.

Some use a pre-flasha softer flash that fires a millisecond before the real flash.

Some use a bright LED that temporarily blinds your subject. Some cameras have

built-in Red-eye Correction that restores natural color AFTER the image has been

captured. Its not a Flash Mode, but its usually more effective than pre-flash. You can

also remove Red-eye in Photoshop.

Second Curtain (or Rear Curtain) Synch

The shutter is not simply a window that opens and closes. Often its more of a moving slit; that is, the first

curtain opens and is still traveling when the second curtain begins to follow it. Normally, the flash fires as

soon as the shutter opens. When set to Second Curtain (or Rear Curtain) Synch the flash goes off just before

the shutter closes, which affords enough time for ambient light to impact the exposure. Use this mode to

capture mood lighting or to show the natural lights that appear in the background behind your subject.

Flash Bracketing

Flash bracketing is the same as regular exposure bracketing, except that that flash is the illumination source.

This is an underused feature partly because few cameras implement it well except at very close range (despite

what their instruction books claim). For rapid-fire Flash Bracketing the flash must be able to recycle very

quicklyalmost instantaneously. Play with it and use it if you can.

Creative Assignment

Turn your flash OFF indoors and ON outside. Thats rightthe opposite of what youve

thought (or been taught) all these years. Youll see a positive difference in your photos

right away. Some will turn out positively awful, but more will be greatly improved. As


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you practice this exercise you will learn which situations benefit from Flash ON and which from Flash OFF.

Cycle through the various Flash Modes; heres how. Find a suitable subject, indoors in relatively dim light.

Humans work well (zombies are okay too, for the Red-eye portion) as do other mammals. Try your best to

keep the distance the same and, of course, dont change the ISO or zoom. Shoot one or two images using each

of the various Flash Modes. Compare the results and decide which yielded the best image.

Bounce your flashno, no, dont throw it!deflect the light toward the ceiling by taping a business card at a

45-degree angle in front of the flash tube. If youre using an accessory flash that has bounce capability you

probably wont learn anything new from this assignment. Make sure you are shooting where there is a

standard height (8-foot) ceiling so that enough light will be reflected down on your subject. This technique

works great for portraits. Also try rotating the camera 90-degrees and bouncing the flash off of flat, white wall.

(Note that if the ceiling or wall has a strong color it will tint the resultant image.)

For Nerds Only: Strobes and Slaves

Some of the old-timers down at the camera shop may call them strobes but, strictly speaking, theyre not.

Strobes blast a string sequence of psychedelic flashes whereas a Flash emits just one

powerful blast.

Slave Units are self-contained accessory flashes that fire when activated by another

flash. They have a light sensitive sensor that triggers ignition when hit by the sudden

burst of a flash. Since the cameras Flash Synch Speed is typically a slow 1/250 of a

second and the Flash Duration a speedy 1/30,000 or so, there is plenty of time for one flash to fire and set off

a second while the shutter is open. After all, this is happening at the speed of light, and thats as fast as it gets.

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