Capturing great shots is involves some camera equipment, a keen eye, patience, and practice. For camera equipment, you need a lens to capture a scene and a camera body to record your image.
Camera lenses come in all kinds of shapes and sizes, and they all have a different purposes. Every lens falls into one of two categories; a prime lens or a zoom lens.
To find more information about the zoom lens, read our article below.
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What Is a Zoom Lens
There are two types of lenses, zoom, and prime. A prime lens sits at one end of the spectrum, working with a fixed focal length. Zoom lenses are at the other end and work with variable focal lengths.
To give you an example, a prime lens, such as the Canon EF 85 mm f/1.4L has one focal length – 85 mm. A zoom lens, such as the Canon EF 24-70 mm f/2.8L has a range of focal lengths – hitting everything between 24-70 mm.
This is easy to remember, as we are already familiar with what zooming in does. Take the 24-70 mm lens, and place the focal length at 24 mm – the widest angle of view. If you move the focal distance ring towards the 70 mm mark, you will find you ‘zoom’ into the scene.
Every lens falls into one of these two possibilities, whether the lens is wide angle, standard or telephoto. If you wanted to know what lens you have, the information you need is already on the lens. If you only see one focal length, then it is a prime lens.
You might be wondering why prime lenses are important if zoom lenses hit the range that the prime lenses do. For example, the three lenses 11-24 mm, 24-70 mm and 70-300 mm cover almost every focal length possible.
Like most things in life, the things that offer versatility don’t necessarily perform 100% across the board. A zoom lens will have an optimal focal length where the focus is the sharpest. It is versatile, but don’t expect it to capture amazingly throughout its entire range.
This is down to a few things. Zoom lenses generally need more mechanics and optical elements within the glass for it to operate at different focal lengths. These extra parts co-operate but also cause their own problems.
A prime lens has superior lens quality. Generally speaking, they can reach much wider apertures.
This makes them perfect for low light conditions and creating bokeh. However, with these lenses, you need to move to change the framing of your scene.
Isn’t There Another Type of Zoom Lens?
Well, you aren’t wrong. The above zoom lenses work with SLRs, DSLRs, medium format cameras as well as mirrorless systems. This is because they are interchangeable and give you an optical zoom.
There are camera systems that don’t have interchangeable lenses. These are point-and-shoot or bridge cameras. As these lenses are not interchangeable, they may use digital zoom.
An optical zoom means the lens changes its physicality and extends beyond the camera. This brings elements of a lens into a different position. This keeps the quality of the image high.
Think about walking closer to a painting in an art gallery. You would see more and more detail that makes up the image. Optical zoom is like increasing the size of a jpeg, where the quality falls away with each increase.
When you see a digital camera’s specifications, the optical and digital zoom measurements are listed. They are a number alongside an ‘X’. Examples might be 3X or 10X, where a larger number means a stronger magnification.
The one thing to bear in mind is that not every camera’s 10X is the same. This is down to the manufacturer measuring the optical zoom from one extreme of the lens’ capabilities to the other.
The multiplier is the difference between the smallest and largest focal length of the lens. For example, if a lens has a minimum focal length of 35 mm, a 10X zoom will give it a 350 mm maximum focal length.
On top of this, the lens might offer some additional wide-angle capabilities. If there is a minimum 28 mm equivalency, then the maximum focal length on a 10X optical zoom would mean 280 mm.
The focal length is written down in the camera’s specifications. Look for something along the lines of ’35 mm film equivalent: 35-350′.
A 50 mm lens measurement is considered standard. It has no magnification or wide angle capability.
If you are looking to compare the overall zoom range of a particular lens, it is important to consider the 35 mm film equivalent number. This will change among lenses. This information is found alongside the focal length range.
Optical zoom measures the actual increase in the focal length of the lens. The focal length is the distance between the center of the lens and the image sensor. By moving the lens further away from the image sensor, the zoom increases.
This is down to a smaller part of the scene striking the image sensor, resulting in a magnified scene.
Optical zoom will be smooth and easy to change, allowing you to stop anywhere within the range. Some digital cameras will use distinctive stops along the length of the zoom. This will limit you to between 4 and seven partial zoom positions.
The digital zoom measurement on a digital camera is, for lack of a better word, worthless. Here, the camera shoots the scene, crops it and then magnifies it to create an artificial close-up image.
This process requires the camera to remove pixels, which causes image degradation. There is no difference with using digital zoom and cropping into the image during post-processing.
If you don’t have access to image editing software, you can use digital zoom for the same crop process.
Advantages and Disadvantages of a Zoom Lens
- A zoom lens offers you versatility. A prime lens only gives you one focal length, meaning that you need to move to reframe your image.
- Allows for more creativity. With a zoom lens, you can compose and crop a scene in camera and experiment with many compositions.
- Many zoom lenses rival the sharpness of prime lenses. As the sharpness increases, so does the price.
- Comparatively, zoom lenses take up less space and weight. To reach the range of focal lengths you get from a zoom lens, you will need many prime lenses.
- Theoretically, you only need one or two zoom lenses. Two zoom lenses could fill your entire shooting requirement.
- Zoom lenses allow more experimentation. Zooming in while you photograph isn’t possible with a prime lens.
- Lower end zoom lenses also have a variable aperture. The Canon EF 70-300 mm f/4-5.6L telephoto lens has a minimum f/4.5 at 70 mm, but it will increase gradually to f/5.6 at 300 mm. As the lens extends from the body, the lens needs to let in more light to compensate for the increase of distance.
- Beginner-level cameras suffer from increased noise. With the extension of the lens, the captured pixels suffer from poorly captured pixels. this results in a loss of quality, especially seen with digital zoom lenses.
- Apertures are not as wide as they could be. Zoom lenses have mechanics and elements within them that hinder their aperture. Typically, zoom lenses have a wide aperture of f/4. F/2.8 is the widest aperture you are going to see on a zoom lens. this number falls to f/1.2 on a prime lens, giving you four extra stops of light.
- Maximum zoom can cause distortion. Pincushioning is a distortion where the edges of a photo appear stretched. Horizontal lines will curve towards the center of the frame.
- Slower shutter response. When using a maximum zoom magnification, the shutter response time slows down, causing blurry images. This could cause you to miss important and spontaneous images. These problems are heightened when shooting in low light situations.
- Using a long zoom lens can cause camera shake. Some cameras have IBIS (In Body Image Stabilisation) to counteract this. Long zoom lenses, otherwise known as telephoto lenses can also have image stabilization built in.
There you have it, everything about zoom lenses. Let us know in the comments below if you’re a fan of zoom lenses and which ones are your favourites!