The most difficult function of photography for me to grasp as an amateur photographer was manual mode. The three things we need to consider are the shutter speed, ISO, and aperture. These are the three things we need to understand before we can take the big leap from program to manual.
As you read the, grab your camera so you can follow along with your camera, be sure to set it into manual mode so you can access every setting.
The Mystery of Aperture
Aperture is often the most difficult concept for people to grasp when they're learning how their camera works, but it's pretty simple once you understand it. If you look at your lens, you can see the opening where light comes through. When you adjust your aperture settings, you'll see that opening get bigger and smaller. The larger the opening, or wider the aperture, the more light you let in with each exposure. For example, a narrow aperture is great for landscapes. A wider aperture means less of the photograph will be in focus, which is something that's generally visually pleasing and isn't seen as a downside. If you've seen photographs with a subject in focus and beautiful blurred backgrounds, this is often the effect of a wide aperture. Using a wide aperture is generally considered the best method for taking in more light because the downside—less of the photograph being in focus—is often a desired result.
Aperture is represented in f-stops. A lower number, like f/1.8, denotes a wider aperture, and a higher number, like f/22, denotes a narrower aperture. This is where I started to get confused. My confusion came because I did not understand that all lenses didn't do the same thing. For example, if you are shooting in low light, the lens that came with your camera is probably somewhere in the f/3.5 range. I knew my camera setting could go to say f/1.8 but with the lens on my camera only went as low as f3.5 so I was unable to set the camera any lower than the lowest range on my lens which was f3.5. When I finally figured this out, I ran up to my studio and borrowed a lens that was f1.8 and that is when I started to understand aperture.
The best thing to do to test this out is to borrow or rent a lens that goes to f1.8. I sat on my sofa with the lights off and took my f3.5 lens, set the aperture to the lowest possible setting for that lens. I propped the camera on my knees and focused on my bookshelf across the room. The shutter speed will come in later but simply, the higher the shutter speed, say 400 the faster the lens opens and closes allowing less light can get in. A high shutter speed is good for stopping action or blur. A lower shutter speed allows for more light because the lens stays open longer, but the longer the lens stays open, the more chance of blur. That is why you will need to prop the camera on your legs or use a tripod.
Lenses are often marked with their widest possible aperture. If you see a lens that is a 50mm f/1.8, this means it's widest aperture is f/1.8. The aperture can always be set to be more narrow, but it won't be able to go wider than f/1.8. Some lenses will have a range, such as f/3.5-5.6. You'll see this on zoom lenses, and it means that when the lens is zoomed out to the widest position it's f/3.5, but when it's zoomed in all the way it can only have an aperture as wide as f/5.6. The middle changes as well, so halfway through the zoom range you'll end up with a widest aperture of about f/4.5. An aperture range is common with less-expensive zoom lenses, but if you pay more you can get a standard aperture throughout the range.
Now, sitting in the dark with your f3.5 lens on, turn off your flash, set you shutter speed to around 100, set your aperture to f3.5 and take the shot. You will notice that the image is very dark because you are unable to get enough light into the camera. Next, put on your f1.8 lens and set your aperture to f1.8 with the same shutter speed and take the shot. You will notice that your image will appear much lighter. This is the magic of a low f-stop. Play around with the shutter speed as well. You will notice the same effects. As you raise your shutter speed, the less light will get in and the darker your image will appear. Now set your shutter speed to a lower setting (make sure you camera is mounted on your leg, a table or tripod so there is no movement and try again. You will see that now, the image will appear lighter.
That's pretty much all you need to know about aperture. The important thing to remember is that a wide aperture, like f/1.8, lets in more light and provides a shallow depth of field (meaning less of the photo appears in focus). A narrow aperture, like f/22, provides deeper focus but lets in less light. What aperture you should use depends on the situation and the type of lens you're using, so experiment to see what effects you get and you'll have a better idea of how your aperture setting affects your photographs.
Last we will discuss price. Generally, the lower the f-stop of the lens, the more expensive it is. Go to ebay and search canon lens 70-200mm f2.8 then search canon lens 70-200mm f4.0. You will notice the price is very different. The low f stop lens is around $2000 where the higher f-stop lens is almost $1000 less.
The Mystery of Shutter Speed
When you press the shutter button on your camera and take a picture, the aperture blades take a specific amount of time to close. This amount of time is known as your shutter speed. Generally it is a fraction of a second, and if you're capturing fast motion it needs to be at most 1/300th of a second. If you're not capturing any motion, you can sometimes get away with as long of an exposure as 1/30th of a second. When you increase your shutter speed—the length of time where the sensor is exposed to light—two important things happen.
First, the sensor is exposed to more light because it's been given more time. This is useful in low light situations. Second, the sensor is subject to more motion which causes motion blur. This can happen either because your subject is in motion or because you cannot hold the camera still. This is fine if you're photographing a landscape at night and the camera is placed on a tripod, as neither the camera nor your subject is going to move. On the other hand, slow shutter speeds pose a problem when you're shooting handheld and/or your subject is moving. This is why you wouldn't want a shutter speed any slower than 1/30th of a second when photographing handheld (unless you're known for your remarkably still hands).
In general, you want to use the fastest shutter speed you can but there are plenty of circumstances where you'd choose a slower shutter speed. Here are a few examples:
1. You want motion blur for artistic purposes, such as blurring a flowing stream while keeping everything else sharp and un-blurred. To accomplish this you'd use a slow shutter speed like 1/30th of a second and use a narrow aperture to prevent yourself from overexposing the photograph. Note: This example is a good reason to use the Shutter Priority shooting mode discussed in the previous lesson.
2. You want an overexposed and potentially blurred photograph for artistic purposes.
3. You're shooting in low light and it's necessary.
4. You're shooting in low light and it's not necessary, but you want to keep noise to a minimum. Therefore you set your ISO (film speed equivalent) to a low setting and you reduce your shutter speed to compensate (and let in more light).
These aren't the only reasons but a few common ones. The important thing to remember is a slow shutter speed means more light at the risk of motion blur. A fast shutter speed means low risk of motion blur while sacrificing light.
The Mystery of ISO
ISO is the digital equivalent (or approximation) of film speed. If you remember buying film for a regular camera, you'd get 100 or 200 for outdoors and 400 or 800 for indoors. The faster the film speed the more sensitive it is to light. All of this still applies to digital photography, but it's called an ISO rating instead.
The advantage of a low ISO is that the light in a given exposure is more accurately represented. If you've seen photos at night, the lights often look like they're much brighter and bleeding into other areas of the photo. This is the result of a high ISO—a greater sensitivity to light. High ISOs are particularly useful for picking up more detail in a dark photograph without reducing the shutter speed or widening the aperture more than you want to, but it comes at a cost. In addition to lights being overly and unrealistically bright in your photos, high ISO settings are the biggest contributors to photographic noise. High-end cameras will pick up less noise at higher ISOs than low-end cameras, but the rule is always the same: the higher you increase your ISO, the more noise you get.
Most cameras will set the ISO automatically, even in manual mode. Generally you can stick with the same ISO setting if your lighting situation doesn't change, so it's good to get used to setting it yourself. That said, sometimes lighting changes enough in dark, indoor settings that letting the camera set it for you automatically can be helpful—even when shooting manually.
Combining the Settings
In manual mode you set everything yourself (except ISO, if you set it to automatic), so you have to think about all three of these settings before you take a photograph. The best thing you can do make this easier on yourself is to give priority to one of the settings by deciding what's most important. Do you want to ensure a shallow depth of field? If so, your priority is your aperture. Do you want the most accurate representation of light? Make ISO your priority. Do you want to prevent as much motion blur as possible? Concentrate on shutter speed first. Once you know your priority, all you need to do is set the other settings to whatever is necessary to expose the right amount of light to the photograph.
In manual mode your camera should let you know if you're over- or under-exposed by providing a little meter at the bottom (pictured to the left). The left is underexposed and the right is overexposed. Your goal is to get the pointer in the middle. Once you do that, snap your photo, and it should look just how you want it.
All of this takes lots of practice so it becomes second nature. This is generally why we hire professional photographers. I know this sounds self serving but to be honest, I have been taking personal pictures of my children for years and this still does not come without great thought before pressing the button. I hope this has been helpful and remember to practice, practice, practice.
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