Showing posts from June, 2011

What Makes a Photograph "Good"

We all take pictures, and we can often recognize that some photographs are "better" than others.  But what makes a photograph good?  There's a lot that goes into this question, and certainly to some extent, beauty is in the eye of the beholder.  But at the same time, there are many things that distinguish photographs as being "good." There are at least three things that photographers should take into account:

Exposureis the amount of light that is recorded by your camera's sensor.  If too much light comes in, the photo will be too bright, and if not enough comes in, it will be too dark.  Proper exposure is the amount of light that gives you the results you want.  Your exposure is controlled by three factors:  the length of time the shutter is open (shutter speed), the size of the opening in your lens (aperture), and the speed of your camera sensor (ISO).  You can change any of these settings manually and balance that change by adjusting one or both of the o…

Getting Started in Photography

People come to a blog like this for many reasons.  But among beginning photographers, I suspect two are more common than all the rest together.  On the one hand, perhaps you're taking lots of pictures with your camera. You take pictures of your kids, the places that you go on vacation, and the great events in your lives.  But perhaps you would like to do more--you would like for photography to become a means of artistic expression.  On the other hand, perhaps you bought your digital SLR because you want to make photography a serious hobby and learn the craft.  You want to use the manual settings on the camera, and not just rely on the automatic shooting modes that do much of the thinking for you.

Of course, these two reasons are not unrelated.  They are intimately connected to each other.  Photography is a nexus of craft and art.  We must engage the right side of our brains to create artistic images, and we must use the left side of our brains to master the techniques of the craf…

White Balance

Unless you've trained your eyes to do so, you may not notice the differences in the color of light in differing situations.  But different light sources actually have different "color temperatues."  Indoor lighting varies in color temperature--tungsten lights are redder than fluorescent.  The above photograph was lit entirely by my daughter's night light--look how red the tungsten light looks on her face. Outdoors, the color of sunlight will change based on the amount of cloud cover and even the time of day.  Most of us go through life blissfully unaware of this unless we're impacted by the beauty of a sunrise or sunset and notice that the colors we see then aren't the same as what we see during the day.

A pure white object will have a different color cast when lit by different kinds of light (like my daughter's pacifier in the above photo lit by a tungsten night light).  "White balance" allows you to correct for light of different color temper…

Should I Shoot RAW or JPEG Files?

That's a good question, and it's one without an easy answer.  You can find very good photographers that have strong beliefs on either side of the issue.  But we should begin by answering a more basic question--what the heck is a RAW file anyway?

Somewhere in the menu system of your dSLR, you'll find an option to shoot RAW files instead of JPEG files (or to shoot both).  Technically speaking, RAW files are not image files--they are simply files that contain the data recorded by your camera's sensor when you took your picture.  Because of this, you can't just open the file in any application like you can a JPEG file (which is a true image file).  The file must be interpreted by software to generate an image from the file.  And RAW formats are specific for each camera model, so you have to have software that has been updated after your camera was released or you may not be able to edit your files.  Without any work done to them, RAW files often look less sharp than J…

Using your Preview Screen and Histogram

One of the great advantages of digital cameras is that you can look at the image right after taking the picture.  You can zoom in on your photograph to see if your subject is sharp where you want it to be sharp.  If parts of your image are overexposed so that they do not have detail in your preview screen, those parts of your image will blink black & white (I admit it: I call this the "blinkies").  You can know ahead of time if you have exposure problems with your image.   If you are shooting in RAW, you still might have detail in those parts of the photograph, but don't count on it--take the picture again if you can.

But in terms of exposure, the most useful part of the preview screen is what's called the histogram.  A histogram is a graph of the exposure values in your image.  On your preview screen, it will look something like this:
The left side of the histogram represents the darker parts of your image, and the right side represents the lighter parts of your i…

Manual Mode

Just saying the word "manual mode" can be scary for new photographers.  The thought of being in complete control of your camera's exposure often causes beginners to shy away from using it all together.  The sad part about this is that manual mode is actually the easiest way to get proper exposure in certain situations.  There is no shooting mode that is inherently better than any other.  I believe you should use the shooting mode that allows you to most quickly and reliably get the exposure you want.  In at least three situations, this mode is very likely to be the manual mode:
Whenever you are using your spot meter.  Zoom in to the area you want to spot meter, set your exposure manually, and you have it set until lighting conditions change.For Exposure Compensation more than 2 Stops. In many camera models, aperture priority and shutter priority modes limit your exposure compensation of 2 stops in either direction (some models give you 3 stops).  This is plenty for most …

Spot Metering

Your camera is equipped with a light meter that can read exposure values all over the scene you're shooting, and for the most part,your camera uses these readings to give you very reliable exposure settings so you can get the exposure you want.  There are four main types of metering modes that you can choose from:
Matrix/Evaluative Metering.  The default metering mode for any camera is usually called matrix or evaluative metering.  This mode takes exposure readings from throughout the frame and averages them together to give you an exposure reading that gives roughly equal value to every part of the frame.Spot Metering.  Spot metering takes all of exposure values from the center of the frame.  The center "spot" usually covers about 2 or 3 percent of the frame.Partial Metering.  Partial metering is very similar to spot metering, but the "spot" is larger, covering around 10% of the frame.  Some cameras may have partial metering with no spot metering, and some may …

Field Practices to Improve Exposure

One of the challenges of outdoor photography is that you have very little control over your lighting.  Perhaps you've taken pictures on bright, sunny days only to find that on  your computer they simply don't look right.  The bright parts of your image have lost all detail, even though you could see detail when you were there.  Perhaps the colors just don't look as brilliant and saturated as they should look.  The scene looked beautiful when you were there, but your photograph simply does not do justice to your experience outdoors.

This frustration is common among beginning photographers.  The problem comes from the fact that your camera simply cannot see as much light as you can see. You can see about twelve stops of light. Your camera only sees about five to nine stops. This means that your camera cannot record many scenes like you can see them. High contrast scenes, like scenes with direct sunlight and shade, will simply have more contrast than your camera can record…

Shutter Priority Mode

Shutter Priority Mode (Tv or S) works just like Aperture Priority Mode except the dial operations are reversed.   The main dial (by the shutter release) controls the shutter speed.  You set the shutter speed you want and the camera will choose the aperture that it believes will give you the right exposure.  You dial in your exposure compensation, either by turning the second dial or by holding down a button and turning the same dial by the shutter release.

This shooting mode has some very useful purposes.  Whenever you care more about the shutter speed of your camera than the f/stop, consider using this mode.  Here are some possible applications:
Panning shots.  Perhaps you've seen photographs where a fast moving subject (car, bike) is in focus but the background shows a lot of motion blur.  This is achieved by choosing a relatively slow shutter speed and panning with the moving subject.  The camera movement tracks with the moving subject, allowing it to be relatively sharp, while…

Aperture Priority Mode

Now that we have the basic concepts concerning exposure, balancing exposure and exposure compensation in our heads, we need to look a little more closely at how these concept translate into the mechanics of taking a picture.  We need to consider the "shooting modes" or "exposure modes" on your camera that you can use get the image you want.  On your digital SLR, you'll notice a dial near the top, and among other things, you'll see a series of letters.  On a Canon, those letters will be

P  Tv  Av  M
On a Nikon or Sony, they will be:

P  S  A  M
These are all shooting or exposure modes that you can use.  In the grand scheme of things, it makes no difference which one you choose.  As long as you get the shutter speedaperture, and ISO you want, the shooting mode has accomplished its purpose. But some modes are more useful for certain purposes.   It's simply easier to get what you want if you're shooting in the appropriate mode for the situation you…

Exposure Compensation

So far, we've focused mainly on accepting your camera's light meter reading and balancing your camera's automatic exposure calculations.  This approach works well most of the time.  Current cameras take light meter readings from all over the frame and calculate what it believes will give you proper exposure.  But as good as these calculations are, they cannot give you the results you want all the time.  There are generally three kinds of situations that can can require you to adjust your camera's calculations to suit your purposes.

Light or Dark Scenes: When your scene has average tonal values that are either very dark or very light, your camera will try to make them average the tonal value of 18% grey.  This means that in very dark scenes, your camera will be likely to overexpose your image.  In very light scenes, your camera will be likely to underexpose your image.  You will have to adjust your camera's reading to get the results you want.High Contrast Scenes: Yo…

Balancing Exposure

As we discussed in a previous post on exposure, you have proper exposure for your photograph when you have set your threeexposure factors (shutter speed, aperture, and ISO) to give you the results you want--that is, you've let in just the right amount of light to give you the image you were hoping to capture.  But that's just the beginning of the creative process in photography.  You can change the balance of these factors to allow you to take control of the look of your photographs.  Let's review a little of what I mean by this:
You can use a slow shutter speed to create a pleasing motion blur--such as the silky effect on a waterfall.  You can use a fast shutter speed to freeze motion, like a kayaker on rapids.  You can use a large aperture (small f/stop) to create photographs with a shallow depth of field, like a butterfly with a blurry background.You can use a small aperture (large f/stop) to to create photographs with both the foreground and background in focus, like …

What's Depth of Field?

Whenever you take a picture, your camera focuses somewhere some distance away from the camera.  We always hope that this "somewhere" is the subject we want in focus.  Thankfully there is always some distance in front of and behind the place where the camera is focusing that appears to be in focus.  That distance is called depth of field.  The following diagram illustrates the concept.
Wherever your camera is focused, there is a distance closer to and farther way from that point that appears to be in focus.

Notice in the above photograph, the grass at the bottom of the picture in front of the river otter is out of focus.  The grass at the top of the picture behind the otter is also out of focus.  Even the back of the otter is a little out of focus.  My depth of field for this photograph was just wide enough to cover the otter's head and neck.

The depth of field of your photograph will change depending on three factors:
F/Stop.  The above photograph was shot at f/5.6.  If I …

What's exposure?

Exposure is the term we use to describe the amount of light recorded by your camera's sensor.  It is  helpful to think of exposure by analogy of filling a bucket with water.  When you turn on the faucet and water flows into the bucket, bucket is being exposed to water.   If you do not fill the bucket, the bucket is underexposed with water; if you fill it to overflowing, the bucket will be overexposed to water.  Proper exposure is what will fill your bucket--no more and no less.  In photography, if not enough light is recorded, the photograph will be underexposed, and  your photo will appear too dark. If too much light is recorded, the photograph will be overexposed, and it will appear to bright.  Underexpose too much, and you'll lose all detail in the shadows; overexpose too much, and you'll lose all detail in the bright parts of your image.

For the purposes of this website, we'll call "proper" exposure the amount of light that will give you the results you …

What's shutter speed?

Shutter speed is the length of time the camera's shutter remains open.  A long shutter speed will let more light onto your camera's sensor, increasing your exposure.  A short shutter speed let's less light onto your camera' sensor, decreasing your exposure.  If your camera is on a tripod and the scene you're photographing is perfectly still, the shutter speed you choose is largely inconsequential--you can set your aperture and ISO the way you want and set the shutter speed to whatever will give you the exposure you need.

There are two main reasons for taking control of your shutter speed;
Camera Movement. If your camera is not on a tripod (or secured in some other way), it is moving.  When hand holding a camera, you need faster shutter speeds so that the camera's motion doesn't cause blur in your photographs.  A good rule of thumb for lenses without image stabilization (IS) is to ensure you have a shutter speed of the inverse of the focal length of your lens…

What's Aperture and f/stop?

Aperture is the adjustable size of the opening in your lens that allows light to be recorded on your camera's sensor.  The aperture can be set larger or smaller depending on your needs.  The larger the aperture, the more quickly light is recorded on the sensor, allowing you to shoot with faster shutter speeds.  The smaller the aperture, the less quickly light is recorded on the sensor, requiring you to shoot with slower shutter speeds.  Cameras measure aperture by a number called an f/stop.  And unfortunately, here's where common sense comes to a screeching halt.   The way f/stops are calculated, the larger the aperture, the smaller the f/stop number.  So f/4 is a larger aperture than f/8. And to make matters worse, doubling the f/stop number decreases the exposure by 2 stops (1/4) instead of by 1 stop (1/2).  It's good to be familiar with the following sequence of numbers.  As you move from left to right in this sequence, you are decreasing your exposure by 1 stop.  And a…

What's ISO?

ISO is a setting on digital cameras that controls the speed that light entering the lens is recorded on your camera sensor.  The faster your ISO, the quicker your sensor can gather the light it needs to achieve proper exposure.  Changes in ISO are measured in "stops," so if you change from 100 ISO to 400 ISO you've increased your exposure by 2 stops.

Raising your ISO is a great way to handle low light situations.  In darker areas, you generally need longer shutter speeds to allow enough light to fall on the sensor.  If you increase your ISO, though, the sensor will record light faster, and you can maintain faster shutter speeds.  This can help you keep your images nice and sharp even in low light.  The downside to raising your ISO is that your images will become more "noisy."  In photographs, a noisy image will appear grainy, so you want to use the lowest ISO that will give you the shutter speed you need.

Digital SLRs today often allow you to get great results …

What's a "Stop"?

It doesn't take much time hanging around photographers before you hear them using the word "stop" in strange ways.  Apparently, you can have more than one and you can even have a fraction of a stop--for instance, you might hear someone saying that they needed to overexpose a snow scene by 1-2/3 stops.  What is that?
A stop is a measurement of a change in the amount of light captured by your camera's sensor, and it's measured in terms of doubling or halving light.  Doubling the light entering the lens is an increase of exposure by 1 stop.  Halving the light entering the lens is a decrease of exposure by 1 stop.    Suppose you take a picture of a beautiful tree with a shutter speed of 1/30sec.  If you take another picture at 1/15sec (not changing your aperture or ISO), you've doubled the amount of light entering the lens, so you've increased your exposure by 1 stop.  If you take another shot at 1/60sec, you've halved the amount of light, decreasing you…

Photographing Waterfalls, Part 1: Exposure

You've probably seen photographs of waterfalls and cascades that have that nice, silky effect in the water, and perhaps you've wondered how this is done.  Well, it's not as hard you might think.  There are some simple things you can keep in mind that will allow you to achieve the same effect in your photographs.
You get the silky effect in the water by having a long shutters speed.  When there's no wind, everything in your picture will be still but the water.  So if you use a long shutter speed and a small enough aperture, the whole photograph will be sharp except the water.  Since water flows consistently in its channel, the motion blur in the water will give it that flowing, silky effect.  Here are some things to keep in mind:
1.  Go early in the morning before the sun hits the scene.  Direct sunlight will cause too much contrast in your scene, and your picture won't be as attractive.  You will also have a difficult time getting a slow shutter speed.
2.  Set You…

Take Better Photos

Welcome to my new blog.  This blog is designed to help beginning and intermediate photographers increase their vision for photography and wonder for the world around them, to capture the the stuff of earth in pixels.  You'll find lots of "how to" material here--how to shoot waterfalls, birds and other subjects, as well as practical advice about composition, exposure, white balance, and other concepts that directly impact photography.  And you'll likely find a post or two on my personal photographic experiences.

As you may guess from the title, I'll concentrate mostly on nature photography, but I won't limit myself--much of the stuff of earth is made by human hands.