What is Depth of Field (DoF)?
Simply explained, if such a thing is possible, DoF is an area (field) of sharpness (focus) that exists in front and behind the subject you’re trying to photograph. More precisely, it is the nearest point in front of your subject and the furthest point behind your subject that are in focus. This field, is very exact, and is very measurable. I should also mention that this field is perfectly perpendicular to your lens. So that if you tilt your lens, the focal plane shifts with your lens - hence the term "tilt-shift" but that's a theme for another blog.
Circle of Confusion
When you play with DoF you will come across what is known as the "Circle of Confusion" this is an area that will appear to be in focus even though it is slightly out of focus. What happens is that our eyes cannot tell the difference.
Don’t worry, I won’t get into the math of DoF. Fortunately for us, some awesome math geeks, have come out with great DoF Calculators so we don’t have to spend all our time doing math instead of making photographs. However, if you are part photographer and part math-geek, I will have a link at the bottom where you can learn everything you wanted to learn and more about lens optics and all the math that goes into photography. You'd be surprised how much math and science actually goes into photography.
DoF is a by-product of aperture, it is also affected by other factors such as,
Why does DoF occur?
Why it occurs is a function of lens optics, Gauss' Lens construction, physics and many other principles that are beyond the scope of this blog. Check this cool DoF applet that will let you play with the factors and see exactly what happens and why.
For the purpose of this blog, what's important for us to know is that DoF occurs and we can manipulate it by changing one or more of the conditions listed above to achieve different results. Let’s take a look.
All these images were shot on a full frame camera from the same distance - roughly 2 ft. with an 85 mm prime lens. This distance was definitely pushing the limits of the minimum focal distance of this lens. I purposely shot with a prime lens so we wouldn't have to deal with compression from a telephoto. The only thing that has changed is the lens aperture and the shutter speed which was adjusted in order to get the proper exposure.
If you want to calculate the DoF yourself, you can use this calculator from DoF Masters. Here's the link DoF Masters Calculator
There will be times when you want to use a shallow DoF to isolate your subject and guide the viewer's eye to where you want them to focus. A shallow DoF is especially useful when you're trying to eliminate clutter, busyness or anything that distracts from your subject. Since our eyes naturally gravitate towards things that are in focus, you need to give your viewer's eye a place to stop. You must be careful not to use too shallow a depth of field or you may get too much of a blurry subject. When everything is out of focus, our eyes wander, searching for a place to rest - that place is anything that is in focus.
The opposite is true, there will be times where a wider DoF is called for. For example when you're shooting a landscape or when you need some context in your picture.
In the photograph below, I have certainly isolated my subject, but I am so close to the subject that some of the subject is blurry. If you look at the calculator next to the example, my depth of field at 2 feet is .01 feet. That means that the area of focus in front of and behind my subject is 1/8" deep (which includes my subject). Well, 1/8" is not very deep. No wonder there is a very small area of my photo that is in focus.
On the second image, shot at F16, the DoFis much wider - more of the picture appears to be identifiable. We can see some rocks, buildings, the lake. By changing your DoF, you can control exactly where you want your audience to look.
Now let's see a few examples. Each photograph has been shot at different depths of fields. You can see thee different levels of blurriness in each picture. You can click on each photo to make them larger.
While my use of a shallow DoF is more utilitarian when I'm photographing shelter animals, I usually have to hide all sorts of distractions. it doesn't always have to be done for this purpose. Shallow DoF is also an artistic choice and a creative way to pop your subject out of the photograph for greater impact. What DoF to use is up to the creativity of each photographer. Do you have preferred DoF? I usually adapt my DoF to the circumstances.
This blog was created as part of a weekly challenge. Each subject encompassing a new focus or photographic technique. Stop by to visit us next week.
To see more examples of this week's theme, please visit: Ashley Siemon Photography, Serving the San Francisco Bay Area and Northern California.
In photography, lighting is everything. After all, photography does mean painting with light. Whether shooting in natural or studio settings, you will always find a photographer chasing the light. This has never been more true than when photographing portraits. It doesn't matter if your subject is a dog, a cat, a gerbil or a person.
So what exactly are catch-lights? Catch-lights are those specs of light reflected on a subject's eyes. They can be the result of natural light, when you place your subject next to window, for example. They can be reflections from the sun, or if shooting indoors they can be the result of artificial lighting like a lamp, flash or other source of lighting. Regardless of where you're photographing (indoors or outdoors), always try to get that gleam of light your subject's eyes.
Pictured above is Zeke, a sweet and highly intelligent pup I doggy sit for every now and then. We have dubbed him the Philosopher because when you look at him, you can truly see the wheels turning inside his brain. He's always thinking, assessing a situation. Zeke is showing us two examples of natural catch-lights obtained by placing your subject facing the light source - in this case, the sun.
The picture of this Labrador/Border Collie, Silas, was taken inside my vehicle during "Golden Hour". The light was entering the car from the right side, as you can see from the highlights on the right side of Silas' face. So catch-lights can be obtained under many circumstances, not just from artificial or studio lighting.
It is important to make sure your subjects never stare at the sun, not even for a second as this can cause permanent damage to their retinas. Instead, place your subject with the sun in front or to the side to obtain the catch-light effect. Remember, facing the sun does not mean staring at the sun.
On the two pictures below, the sun lights up the dogs' eyes allowing for a reflection of the landscape. The top parts reflect the sky, while the lower parts reflect the snowy landscape.
This beautiful Cattle mix pup is another example of natural catch-lights. The bottom part looks white because it's a snow covered landscape. There were 11 puppies in this litter, every single one of them had absolutely stunning coloration. Needless to say, they were all adopted rather quickly.
Pictured above is Mojo, another pup I doggy sit for. Here we were enjoying a gorgeous sunny day in Northern Wisconsin - it was sunny and probably around 30 degrees - which is almost summer! I had my wide 24-70 on my camera when Mojo came and sat right next to me. He looked towards me and click. I took his photo. His beautiful caramel colored eyes, would not be anywhere near as visible or dramatic if he had been facing away from the sun.
However you achieve them, through natural or artificial means, catch-lights are a simple and beautiful way to brighten up your subjects' eyes and instill life and vibrancy into your photos.
This blog was created as part of a weekly challenge. Each subject encompassing a new focus or photographic technique. Stop by to visit us next week. A new blog will be published each Friday.
To see more examples of this week's theme, please check out:
KME Photography in Minneapolis, MN.
This past Saturday in Bayfield, we celebrated the 21st Annual Apostle Islands Dog Race. I look forward to this event as it affords me an opportunity to watch these dogs enjoy what is perhaps their favorite activity. Yes, sled dogs are happiest when they are pulling a sled – at least the ones I saw this past weekend. Their excitement is so great, it overflows out of their slim athletic bodies and it’s exhibited by their “flying” or singing - I would even call it complaining. For these dogs, the starting signal cannot come soon enough. They have no time or patience for fanfare or celebration, or for the necessary waiting time between teams. No, sir, they just want to go, go, go.
As for us humans the weather couldn't have been more perfect or more incredible. A mild 35 degrees in the middle of February was just right to spend a lot of time outdoors, but a bit troubling at the same time. We should not have such warm weather this early in the year, but while the temperature was ideal for us, I believe the dogs would have preferred it to be slightly colder. Warm or Cold, however, they were ready to run. So here are but a few of my favorite pictures which show their mood on that day.
Jumping for joy, for excitement, whatever it is. This darling sure can fly.
Pride, joy. The white dog on the right seems to exhibit all those traits as he and his team prepare for their turn at the starting line.
Determination, excitement, joy, focus - all those traits are exhibited here.
The dogs on the left appear to have confabulated with one another to bring us their synchronized tongues. These photos were taken around the mid-way point, so much of the intense energy built up during the start has already been spent.
21ST. Apostle Islands Sled Dog Race