I receive emails asking for photography tips and thought I would try to explain what I think is important. If you own a DSLR camera, you want to stop shooting in auto mode. Understanding aperture, or the A or AV setting on your camera is where taking control of your photography begins. I'd like to do my best in explaining this function. Please keep in mind that I am not a professional, and everything I have learned about photography, I have taught myself. So, I hope I do not confuse you, as this is one of my lengthiest (and driest) posts. Please feel free to correct me if I have a misstep.
Aperture and Depth of Field 101
The main function of a camera lens is to collect light. There are two main functions for collecting light; the
aperture and
shutter speed. How
little or how
much light enters your camera while taking a photo will affect the overall outcome or exposure of the photograph.
- Too little light = underexposed, or very dark.
- Too much light = overexposed, or very white.
- A properly exposed photograph will have just the right amount of light.
When shooting in auto, your camera automatically evaluates the subject based upon how much light is available and adjusts the camera's settings for aperture and shutter speed automatically.
If you want more control, switch your camera's setting to Aperture Priority or the 'A' or 'AV' mode. This will allow you to control the aperture. The camera will then automatically adjust the shutter speed (which we'll discuss later).
The aperture of a lens is the diameter of the lens, that opens and closes when you take a picture.
Think of it like the pupil of your eye. When there is a lot of light available, the pupil will constrict and become smaller, allowing less light to come in. When there is little light available, your pupil will dilate or expand, allowing more light to come in.
The aperture of your lens works in this way:
- A smaller lens opening means less light is collected.
- A larger lens opening means more light is collected.
When taking a photograph, you can set the aperture of your camera to be very open, closed very tightly, or increments in-between. The settings of the aperture openings are called "f-stops". This is where it gets confusing because it's kind of counter-intuitive, but you'll get the hang of it. Below is a diagram I created showing the relationship between the lens' opening and the corresponding f/stop.
- The smaller the number (or f/stop) --> the larger the lens' opening --> the larger the aperture.
- The larger the number (or f/stop) --> the smaller the lens' opening --> the smaller the aperture.
- F/1.8 has a large lens opening. F/22 has a small lens opening.
- F/1.8 is a much larger aperture than F/22.
Depth of Field
Which aperture you choose depends on the depth of field you want.
Depth of field or
DOF is how much of the photo is in focus, and how much of the photo is not in focus.
Think of it like this: small numbers mean small DOF. Large numbers means large DOF.
Shallow Depth of Field
A
shallow depth of field means that the subject is in focus but the background is out of focus. Shooting with a large aperture (small number) - f/1.8 - creates a shallow depth of field. Shallow depth of field is great for portrait photography.
Let's go back to the example of the eye. Think about when you go in for an eye exam and the optometrist dilates your pupils. The dilation drop expands the pupils so the optometrist can see all the way into the back of the eye. The pupil or "aperture" becomes wide open. Your vision becomes very blurry. Your depth of field becomes shallow as you may be able to focus only on one subject while the rest of the picture is fuzzy. Your vision also becomes highly sensitive to light, again, because your pupil is wide open.
Here are some examples of photos with shallow depths of field:
Notice in all three of these pictures, the subject is isolated and in sharp focus, while the background is out of focus. All three of these pictures were taken on the A setting on my
Canon T1i Eos Rebel with the largest possible aperture setting on my camera's 50 mm lens - f/1.8.
If you are new to DSLR photography and you have a Canon, I highly recommend buying this lens. It is $100 and will produce these types of effects. The 50 mm f/1.4 is three times the price.
Note, that if your lens allows you to go this large, always switch it back to at least F/2.2 or F/2.5 when taking outfit pictures or pictures with more than one subject. I don't know how many times I have taken outfit pictures on f1/8 to find the photo batch completely blurry and unusable.
Large Depth of Field
Shooting with a small aperture (large number) - F/22 - means that foreground, background, subject - everything - in the photo is in equal focus. Shooting with a small aperture is ideal when shooting landscapes because you want objects both near and far in focus.
Here are some examples of photos with large depths of field:
Notice that everything is in focus in these three photographs and you can see all the of details.
Play around with the different apertures and see the different effects each f/stop produces on the A or AV function of your camera. Go to the absolute smallest, to the absolute largest and every increment in-between. Messing around with the settings is the best way to learn.
I hope this helpful and not too much information or too confusing. It can be a lot to rack your brain around but totally worth it once it makes sense. Next, I will be explaining shutter speed and ISO. I will also post how to amp up your photos in the post production process.
P.S. Winner of the Stella & Dot giveaway is Jennifer Baker! Congrats! We'll be in touch.
