Understanding Camera Lenses for Beginners
Camera lenses are a vital component that aids your camera operation. Whether you are using a DSLR, a mirrorless camera, or iPhone 11 pro max you need to have an appropriate lens. In general, a suitable camera lens enables you to control how your images will appear. Similarly, they also influence on both the creative and technical facet of photography.
In this article, you’ll learn how light transforms into an image. Firstly, you need to master the different components of the camera lens. Moreover, it will help you figure out how lens type, aperture, and focal length influence imagery. Secondly, you’ll understand the offset with prime lenses against zoom or fixed focal lenses. Thirdly,and most importantly, you also need to know how to use wide-angle lenses in the next episode. In conclusion, discover more about telephoto lenses suitable for magnifying distant subjects.
HOW DO CAMERA LENSES WORK?
Usually, a photographer who understands camera lenses has more creative control in the field. However, selecting the right lens for the assignment can be arduous. Most importantly,you must contemplate between odds and ends such as
• Lens speed
• Image quality
To be sure, let’s begin with a brief of concepts that will help you understand how camera lenses can influence:
• Focal length
• Prime versus zoom
• Image quality
CAMERA LENSES ELEMENTS
We have seen computer storage advancing from megabytes to gigabytes and now terabytes. However, with lenses, it’s still not distinct, whether more is superior.
When you look at your lenses, you’ll see a listing of the number of elements it has. Usually, elements are respective glass elements inside the lens itself. That is to say, camera lenses are just a collection of several lens elements. In this case, each element controls the path of light rays to revamp the image precisely on the digital sensor. Altogether,the aim is to reduce aberration while still making use of less expensive elements.
In the figure above, the lens elements deliver focus light onto a single point successfully. Conversely, if the points in the scene don’t render back onto a single location, then optical aberrations occur. As a result, you see image blur, low contrast, and jumble colors or chromatic aberration. Other effects lenses may suffer include distortion or vignetting.
Effect of lens focal length
Typically, the focal length of a lens controls:
• Its angle of view.
• The angle between the edges of the entire field of view.
• Magnification of a particular scene in photography.
A splendid example is that wide-angle lenses and telephoto lenses. Here, wide-angle lenses have short focal length whereas telephoto lenses have longer focal lengths.
Sometimes, photographers say that focal length also determines the perspective of an image. Perspective is how your subject seems with one another when viewed from a particular standpoint. Notably, perspective can only change with your location respectively to the subject. For instance, if you use a wide-angle lens and a telephoto lens, perspective changes. However, you achieve the same framing because you are moving closer to or farther from your subject.
In the figure above, we have the same subject in the frame taken with different lenses. To deliver the same framing, you have two options. One is to step back further when you are using a longer focal length, and vice versa is true. Here, the wide-angle lens stretches or extends perspective. Conversely, the telephoto lens flattens perspective, making your object appear closer than in reality.
Typical focal lengths
The illustration below shows what focal lengths are essential for a lens for wide-angle or telephoto lenses. In essence,the list is an overview, but actual uses on the ground may vary slightly. For example, some photographers prefer to use telephoto lenses in distant landscapes, especially when they want to compress perspective.
Additionally, telephoto is more prone to shake. That is to say that it amplifies even the smallest hand movement when your angle of view is narrower. However, wide-angle lenses are more resistant to flare due to their design.
Compact cameras, DSLR and Mirrorless cameras have original sensor size. In summary, to adjust the numbers, check online for your camera’s crop factor then multiply by your lens focal length.
Effects of Focal length on sharpness
Usually, focal length alone will not control the sharpness of the image you take. It helps you reach a sharp image when operating handheld photographs. In fact, longer focal length minimizes blurring, which results from shaky hands.
An excellent example is when you take hold a laser pointer steady. Pointing it to nearby objects makes the bright spot appears more constant whereas jumps around on farther away objects.
For this reason, there’s a slight magnification with distance on rotational vibrations. Especially, if you have side-to-side vibrations, the laser’s bright spot doesn’t correspond to distance change. It means that longer focal length lenses are prone to shaky hands. Here, they magnify distant objects more if you compare it to shorter focal length lenses.
One over focal length rule gives you a rough estimate of how fast the exposure should correspond to focal length. For example, if you are using a 200mm focal length on a 35 mm camera:
• The exposure time will be over 1/200th of a second. Any figure less than that will cause blurring.
However, if you use a digital camera with cropped sensors, convert it into a 35mm equivalent focal length. Cropped sensor cameras example includes:
• Micro four-thirds cameras
• APS-C cameras
• Compact cameras
A zoom lens is a camera lens comprising a mechanical assembly of lens elements with varying focal lengths. With a zoom lens, you don’t have to change lenses to achieve perspective or variety of composition quickly. As a result, it becomes easier for capturing dynamic subjects such as photojournalism.
Furthermore, working with a zoom lens gives flexibility since you need not change your location. We have two factors that influence this:
• Zooming in. Works by changing the composition.
• Moving in and zooming out. Works by changing perspective but maintains the composition.
A zoom lens will enable you to avoid cropping images or changing positions more often. In essence, you’ll get a tighter composition by zooming in on the subject. Another way of changing perspective is to zoom out and move farther from the subject.
Prime lenses (fixed focal length lenses)
We also know a prime lens has a fixed focal length lens and allows a user to zoom in or out. Notably, with a prime lens, you cannot very focal length within a range. The prime lens offers myriads of advantages over their commercial counterparts. They include:
Many photographers will agree that an inexpensive prime lens delivers crisp images as a high-end zoom lens. In brief, an excellent prime lens will offer you a larger maximum aperture or robust light gathering ability. Usually, when working on low light sports or theatre photography, light-gathering expertise will help.
With compact camera lenses, a 5X, 6X, or higher mean the ratio between the longest and shortest focal length. To point out, more towering zoom figures don’t translate to image magnification. Again, that could also mean that the zoom when fully zoomed out has a wide-angle of view. Moreover, the optical zoom is a distinct thing from digital zoom. A digital zoom enlarges the image through interpolation. In fact, it is the one responsible for degrading detail and resolution.
Influence of lens aperture f-stop
An aperture in photography is the opening of a Lens diaphragm where light passes. Generally, you’ll see aperture numbers written as 1.4, 2, 2.8,4, and more. It is calibrated or listed in f-numbers where lower f-stop gives more exposure. Notably, an aperture range of a lens is how much the lens can open up or close to allow light. It can be more or less, depending on your choice.
It’s important to note that a larger aperture opening delivers lower f-numbers. Example:
• Having a lower f-stop makes the lens opening to widen and gives less depth of field. Here, your background will blur more.
• A higher f-stop makes the lens opening to narrow and gives a greater depth of field. Here, your background will become sharper.
Typically, when you look at your lens front, there’s a specification listed there known as maximum aperture. Now, you’ll enjoy artistic flexibility if you have a lens with a more excellent range of aperture settings.
You need the highest maximum apertures when working on indoor sports photography, portraits, or theatre photography. It is capable of a faster shutter speed or a narrower depth of field. The smaller depth of field helps isolate your subject from the background when doing portraits. When working with a DSLR camera, you’ll notice that a lens with a larger aperture delivers brighter images. Such is suitable for low light photography and night scenes.
Additionally, the maximum aperture has advantages when doing manual focusing. The image in the viewfinder will have a narrower depth of field, giving it more visibility.
In summary, we do not often use the maximum aperture because of photo blurring of lens diffraction. Another drawback is that they require longer exposure time to execute the work. If you aim to achieve the extreme depth of field, then go for lenses with a smaller minimum aperture. Again, a larger maximum f-number will work in this scenario to allow for more extensive depth of field.
Range of maximum aperture
Sometimes, you’ll see zoom lenses on a DSLR and compact cameras listing a range of maximum aperture. Usually, it refers to the range of maximum aperture and not the overall range. Let’s say we need a range of f/3.5-5.6. Here, it means the maximum available aperture f/3.5(fully zoomed out) to f/5.6(fully zoomed in).