Light, Lines & Color

D is for Depth of Field

Depth of field (DOF) refers to the portion of a photograph that appears to be in sharp focus from the foreground to the background. A photograph with a large depth of field will be sharp from front to back; a photograph with a shallow depth of field will have a limited area of sharp focus with blurred areas in front and/or back of it. A photographer can select or determine the depth of field within a photograph by selecting the aperture, measured in f-stops. Choosing a large f stop number like f/22 will provide a large depth of field; choosing a small f stop number like f/2.8 will provide a shallow depth of field. 

This is just one of those things every wannabe photographer must learn but once you've got it you can start having fun.

On the Outer Banks of North Carolina, I wanted as much of this image as sharp as possible. I focused about one third of the way in to the frame and then set the Aperture to f/18. This gave me a shutter speed of 1/60th second and I didn't want to shoot handheld any slower or I'd probably see shake.

Shot with Nikon D60 with Aperture Priority on f/18 at 1/60th second

In the Smoky Mountains of Eastern Tennessee, we came upon these falls. I wanted the falls as sharp as possible front to back and this time I had a tripod! With my ISO on 100, I set my aperture to f/22 and happily found the camera set the shutter speed to 1/15th second. Happily? Because the very slow shutter speed gave a wonderful soft blur to all that moving water!

Shot with Nikon D60 with Aperture Priority on f/22 at 1/15th second

The most beautiful flowering bush we have in our yard is a blue-lace hydrangea. Every spring it blossoms with the most delicate light blue flowers imaginable. I love the details in each flower and wanted to set one off against the blues and greens of the bush which called for a shallow depth of field.

Shot with Nikon D90 with Aperture Priority on f/5.0 at 1/100th second

Along the "highway" near our home on Long Island, I saw these sunflowers just beginning to flower. I'd never seen them as they were forming and was captivated by their demonish looking blooms. I wanted the bloom to be the center of attention, but I also wanted the image to show what it would become. I focused on the bloom and set the aperture to a shallow f/5.6, allowing the other flowers to remain recognizable and yet to fade into a blur behind the bloom. BTW the fast shutter speed (1/250th sec) helped with the breezes created by the cars and trucks rushing by behind me.

Shot with Nikon D90with Aperture Priority on f/5.6 at 1/250th second

How do you approach shooting for depth of field? Any suggestions?

C is for Camera - Think Like One

Think like your camera ... This is often the only way I know how to set the camera's aperture, shutter speed and ISO. I ask myself (as the camera), "What do I need to do to make the image she wants to make?" The basic tools in our arsenal are the triumvirate: Aperture, Shutter Speed and ISO.

Aperture, the size of the hole allowing light to enter the camera, is expressed in something strange called f-stops. The smaller the f number, e.g. f/2, the larger the hole and the larger the number e.g. f/22, the smaller the hole. (Note: the choice here also determines an image’s Depth of Field, but more on that later.)

Shutter Speed, how long the shutter will stay open, allowing light to enter is expressed in seconds, or fractions thereof.

ISO, the sensitivity of the camera’s sensor to light is expressed in round numbers from 100 to 6200 and higher. The lower the number the less sensitive the sensor, the higher the number the more sensitive.

Lower ISOs create the least amount of "noise" in an image - trust me on this for now, that's bad - so I most often start by setting the ISO on the lowest setting the camera allows, usually 100 for my Nikons. Now, how do I choose between Aperture or Shutter Priority?

If I'm shooting a landscape, I know I want as much of the image to be in focus as possible, the flowers in the foreground, as well as the barn in the background, so I know I want the greatest depth of field and thus a fairly high aperture. Set to Aperture Priority, the camera allows me to select the aperture for the greatest depth of field while still shooting at a shutter speed that would be safe for a handheld shot (which this one of a foggy field in early morning was).

 Taken with a Nikon D60 on Aperture Priority - f/18 for 1/100th second

If I want to capture a child running at the beach, my camera will need to stop the action and thus I'll set it to Shutter Priority and choose a speed that I think should work like 1/1000th of a second. The camera might then give me a wide aperture which will result in a shallow depth of field, but I really want to focus solely on the child's action so depth of field means little to me here.

Taken with a Nikon D60 on Shutter Priority - 1/1000th second at f/5.6

 

B Is For Brightness

Photography is all about light and capturing it in a manner that expresses what you, as the photographer, see and feel. To that end, we are always working with Brightness - trying to tame it, redirect it and/or extract it. Exposure to light/brightness is determined by the triumvirate described in the last post "A is for Aperture" - Aperture, Shutter Speed and ISO. Trust me there will be more on that later - "E" is not so far away.

Every year around the holidays, the village of Montauk, on the far east-end of Long Island, NY, decorates its historic lighthouse beautifully and it stands out incredibly against a dark late-day sky. On a recent shoot at Montauk Light, it was brutally cold as the sun was setting and as much as I wanted to stay to capture the lighthouse at its stand-out best, it was just too painful. When I took my first shots, I could see that they were just too bright and I knew I wouldn't last to shoot later, so I decided to adjust the brightness of my images by adjusting the Exposure Compensation - the EV (Exposure Value). 

Exp: ½ second @ f/11with 0 EV shot at 5:42:14 p.m.

Exp: ¼ second @ f/11 with -1 EV shot at 5:42:28 p.m.

Exp: ¹⁄₆ second @ f/11 with -2 EV shot at 5:44:21 p.m.

Exp: ¹⁄₆ second @ f/11 with -2⅔ EV shot at 5:48:29 p.m.

All of these images were shot with an ISO (sensor sensitivity) of 200 which I chose because it's fairly low and I wanted to avoid "noise" in the images at nearly any cost. As the shot was a landscape of sorts, I shot on Aperture Priority and I chose f/11 as it's a "middle-of-the road" aperture which would give me an "average" depth of field. f/22 wasn't needed for extra depth of field in these images and would have forced me to shoot with longer shutter speeds which most likely would have caused blur given the gale force winds; and, a larger aperture like f/5.6 would have exposed the image to less sharp focus throughout the image from the sign in the front to the lighthouse in the rear, so f/11 seemed the right choice to me at the time. As I took each picture and looked at it in the monitor, I began to reduce the brightness by "stopping down" the EV taking it from 0 EV to minus 2⅔ EV.

Now I have a question for anyone who might be listening and interested in participating in this new forum. If "a one-stop change in aperture will change the shutter speed also by one stop", should the same be true for Exposure Compensation? In Aperture Priority with a fixed aperture of f/11, between the third and fourth pictures I stopped the EV down ⅔ of a stop and yet the shutter speed didn't change from ¹⁄₆ second. Any idea why? The images were taken 4 minutes apart, could it be attributable to increased darkness, or could it possibly be attributable to the extreme cold? Weigh in here, we all want to learn.

At the end of the day, I was disappointed that the weather chased us away before we were able to get the shots we wanted, but these are a fair representation of what the Lighthouse looked like on that blustery winter's afternoon. Now the question is, which is your favorite?

A Is For Aperture

"A" is for Aperture, one of three basic elements that make up the triumvirate of photography: Aperture, Shutter Speed, and ISO. An analogy that has always helped me grasp these seemingly confusing mechanics of cameras is the human eye.

Aperture is the size of the opening in the lens on a camera at the time a picture is taken, which is similar to the size of the opening in the pupils of your eyes. On a bright sunny day, your pupils contract and become quite small, limiting the amount of light that enters your eyes; and when you enter a dark room at night, before the lights are turned on, your pupils dialate allowing much more light in so you can discern what lurks there in the dark. Aperture on a camera works the same way. Small openings limit the amount of light entering your camera and large openings enable more light to reach your camera's sensor.

Aperture is measured in something called f-stops and every photographer has to learn:

• a small f-stop number means a large opening,
• a large f-stop number means a small opening, and 
• changing from one f-stop to the next will either halve or double the amount of light entering the camera.

Schematic borrowed from Wikipedia

And lastly, you should know that the Aperture setting on your camera will determine the depth of field in your image, which is to say how much of it is sharp from front to back. An image with a large depth of field will be sharp from foreground to background; an image with a small depth of field will be sharp in parts and blurred in others.

There will be much more said about the other two parts of the triumvirate later but for now here are some fundamental explanations of Shutter Speed and ISO.

• Shutter speed is the amount of time the shutter is open. Think of when you blink quickly as fast shutter speed, limiting the amount of light that reaches the retina or camera sensor, and think of when you force your eyes to stay open and to blink less often as slow shutter speed, increasing the amount of light reaching your sensors. 
• ISO measures how sensitive a camera's sensor (or its retina) is to light. The lower the ISO number, the less sensitive it is to light; the higher the ISO number, the more sensitive it is to light.

I know this all sounds terribly confusing but understanding these basics of your camera will open worlds of creativity down the road. As we progress down this road together this year, we'll shoot with different apertures, shutter speeds and ISOs and see the results first hand. In the meantime, here's something I didn't know until recently: the word photography is derived from two ancient Greek words that can be translated as writing/drawing with light. Learning the mechanics of your camera enables you to control this light to create images of the world as you see and perceive it.

 

Light, Lines & Color - The Photography Blog

As the tag line says in the heading of this blog, Light, Lines & Color is going to be about the ABCs of photography for photographers and wannabes.

Learning photography can be a daunting endeavor no matter how passionate you are about light, lines and color. First there's the terminology like aperture, shutter speed, ISO and depth of field, then there's understanding the numbers that go with those things, and of course then there's how to use them to create the images you want. But in this digital age, it doesn't stop there. The learning curve is even steeper now as photographers have become their own Kodak lab. Processing images is a big part of being a photographer these days and if you're going to process all your own images, then you must also learn some method of "inventory control" so you can find the images you want when you want them. It can all seem overwhelming - and this is from one who has been wrestling with this learning curve for several years now. 

I have always learned best when I've written down what it was I was trying to grasp, so I've created this blog as a "52 Week Photography Project" to cover what I call the ABCs of photography. Over the next 52 weeks, I'll be covering the basics of cameras, tools, and techniques, and creating images using them all as I go. At the end of the year, I expect we'll all be far more comfortable with this craft of photography with the hopes that we will then be able to create those images that are in our mind's eye. I invite you to join in on this photographic journey. It should be fun and I hope that we will learn from one another. Sharing is a wonderful teacher.

Let's begin with "A is for Aperture" ... in the next post.