I hope in the past week you've gone out and shot lots of pictures in lots of different lighting situations with your DSLR camera. Now, let's talk about those camera settings!
There are many settings on your camera that you can customize, but there are three main settings in your camera that will make a difference in how your camera captures a picture. These three settings are Aperture, Shutter speed, and ISO.
I like to think of these three settings as a sort of triangle. All three settings are connected to one another. When you change one setting, it affects the other two settings as well. The AREA inside of the triangle has to stay the same, even when you change the length of the sides.
Thankfully, our cameras are getting smarter and smarter and picking the best settings for an image, but cameras aren't always right. Sometimes, your intention for a picture is different that what the camera's brain says is best.
So this week, we're going to look at what changing the aperture does to change a photo.
Aperture is the setting on your camera that usually follows the notation "f/", or is referred to as your "f-stop". It's a number or a ratio, often times a decimal, such as 1:1.4, 2.8, 3.5, or 4. The aperture is lens-dependent. Some lenses will have apertures a low as 1.2, and some as high as 22 or even 40!
I like to think of aperture as the "pupil" of the camera's eye. It works the same way our pupil works. When it senses low light, the "pupil" opens wide, and when it senses a lot of brightness, the "pupil" closes down to a much smaller opening. Small numbers mean LARGE openings, and bigger numbers mean SMALL openings.
Aperture is the main setting that is responsible for that creamy background blur, also called "bokeh", that defines and isolates your subject. Christmas is a wonderful time to explore aperture, because Christmas lights provide exactly the kind of background to perfectly demonstrate bokeh.
Scan through the gallery below and look at how the background (the Christmas tree and fireplace) changes relative to the subject (the ornament).
This first example was taken with a 50mm/f1.4 lens. You'll notice in the first picture, it is very easy to tell this is a picture of a Christmas ornament, with a tree and fireplace behind it. The further you scan into the gallery though, the tree and fireplace become blurred and less identifiable. The aperture, or f-stop, on the first picture is f/22, while in the last picture, the f-stop is f/1.4.
It's even more dramatic when I use a longer focal length lens, like a 70-200 f/2.8. Scan through this gallery- going from highest aperture to lowest again.
This goes from an aperture of f/32, a couple steps in between, and finally all the way down to f/2.8.
Notice that the subject (ornament) doesn't really change much despite the changes to aperture. That's because we use shutter speed to balance any change we make in aperture. Modern cameras make this easy for us- they have modes that allow us to control one or two of those three variables and then automatically adjusts the other. However, when you put your camera in manual mode, you get to control all three and ultimately decide how you want your picture to look.
One other important concept in regards to aperture is that aperture controls your DEPTH OF FIELD. This is important, because when the depth of field is shallow (your aperture number is low) then the less area is in focus from front to back in your photo. Imagine a ribbon going from left to right in your photo and everything in front of the ribbon and behind the ribbon is out of focus. Well, aperture controls how wide that ribbon is. The higher the number, the wider the "ribbon" or focus area. The corollary to that is the smaller the number, the narrower the "ribbon". This concept is demonstrated in the pictures....if you look a the front of the sled, you will see that the front of the sled stays in focus, but Santa falls out of focus when the aperture is lowest.
You can also see that not only does the size of the blur change, but the shape as well. At the widest apertures (low f-stop numbers) the lights are almost ovoid shaped at the edges of the frame and rounder toward the middle of the frame. This is because the barrel of the lens causes some distortion at the edges. As the f-stop increases, or becomes narrower, the blurry become more round because you are looking only through the center of the lens, and eventually, at the highest f-stops, even have star-like rays of light radiating from them caused by the number of blades that move to open and close in the lens.
Finally, something fun to experiment with....let's get a little crafty and add something that gives US control the shape of the bokeh. So, just get a piece of cardstock or black construction paper and cut it to the approximate diameter of the lens. Then in the middle cut out a different shape, and placing the piece of cardstock with the shaped hole in it on the end of your lens. When you shoot through it, the bokeh shape will change to whatever you cut out! Below I cut a heart and a star (although I didn't cut a very good star shape- lol!!)
I hope you'll get out and experiment with aperture a little this week. Try putting your camera on aperture-priority (Av on a Canon; A on a Nikon), and set the aperture to wide open (using a low f-stop) or stopped down (using a high f-stop). In aperture priority, the camera will respect whatever aperture you set, and then will automatically adjust the shutter speed to properly expose the picture. Look at the difference in the shutter speed when you change the aperture. When you shoot wide open, your camera will use a faster shutter speed than when you stop down. Use a lens cut-out to create differently shaped bokeh. Don't be afraid to try new things and really push the limits of your camera's capabilities! Remember, practice makes perfect, and playing around now may mean that you will apply a concept when you really want to make sure you don't miss the shot!
Keep Smilin'!
Jennifer
