The Ultimate Guide to Choosing the Right Camera Lens

Explore this comprehensive guide to choosing the perfect photography lens. Dive into the different types to find the best fit for your camera.

Author: Marco Crupi

This article is a segment of the Digital Photography Course. Click here to return to the main course overview.

To achieve high image quality in our photos, it’s not just about the camera body; the lens plays an equally crucial role in capturing sharp and detailed images.

There’s no one-size-fits-all lens for every situation. As I mentioned in the previous article on camera types, it’s all about compromises. When choosing a lens, you need to weigh the pros and cons of each option, considering your budget.

The market offers a wide variety of lenses across different price ranges and types. This lesson in our photography course will guide you in selecting the right lens that best suits your needs.

Along with the lens, we often receive a lens hood. But what is its purpose?

• To block stray light, preventing a loss of sharpness and reducing flare.
• To protect the front element of the lens.

Adding any type of filter in front of the lens increases the risk of unwanted reflections. In such cases, using a lens hood is highly recommended.

The focal length of a lens is defined as the distance between the lens’s optical center and the camera’s image sensor, measured in millimeters.

Simply put, our camera’s zoom is determined by changes in focal length: a shorter focal length allows us to capture a wider portion of a scene, while a longer focal length brings us closer to subjects, effectively zooming in. In other words, a shorter focal length (e.g., 18mm) is like stepping back from the action, capturing more elements in the scene, making it ideal for landscapes or group photos. On the other hand, a longer focal length (e.g., 200mm) is like moving closer to the action, isolating subjects or details, perfect for portraits or wildlife photography.

Focal length not only changes the apparent “distance” from subjects but also affects the perception of depth and proportions in a photo. For example, a wide-angle lens can exaggerate the distance between objects in the foreground and background, creating a sense of depth, while a telephoto lens can compress the perceived distance between objects, making them appear closer together than they actually are. I explore this topic further in the section on perspective in photography.

The focal length of a lens is usually indicated on the front of the lens, along with the symbol for the filter thread diameter (important for filters, which I’ll discuss in a dedicated article) and the maximum aperture values.

Based on the focal length, lenses can be categorized into three main types:

• Wide-angle: focal length less than 35mm.
• Standard: focal length between 35mm and 50mm.
• Telephoto: focal length greater than 50mm.

Each focal length corresponds to a specific field of view, meaning the portion of the scene visible through the viewfinder or camera display. While this parameter also depends on the camera’s sensor, we’ll cover that in another article. For now, we’ll focus on the field of view of lenses mounted on a full-frame camera.

The image above illustrates how, as the focal length increases, the field of view becomes narrower; conversely, the shorter the focal length, the wider the field of view.

The lens speed is defined by its maximum aperture. A faster lens allows for better performance in low-light situations. The diaphragm, made of overlapping thin metal blades, adjusts the size of the aperture, controlling the light reaching the sensor.

Modern lenses often use an adjustable mechanism called the “iris diaphragm“, which precisely manages the light intake to achieve the desired exposure.

The term “stop” refers to the difference between aperture values. Each full stop change adjusts light by a factor of two: closing by 1 stop halves the light, 2 stops reduce it to a quarter, and 3 stops to an eighth, and so on.

Lenses with apertures of f/2.8 or wider are considered fast. As shown in the image above, smaller f-numbers indicate a wider aperture, while larger numbers indicate a narrower one.

Aperture also influences depth of field, a topic I’ll explore in another article.

In photography, a standard lens offers a field of view that feels “natural” to the human eye. However, shorter or longer focal lengths can compress or expand depth, leading to noticeable distortions.

Typically, lenses between 35mm and 50mm are considered standard. Unlike the human eye, cameras use flat sensors instead of concave retinas, and our vision relies on two eyes working together. Additionally, the brain processes visual information differently than a camera does.

Therefore, equating human vision to a 50mm lens is misleading. While often claimed to mimic the human eye, a 50mm lens only captures a 46° field of view, much narrower than our natural 95° horizontal and 80° vertical vision.

A wide-angle lens has a focal length shorter than 35mm, making it ideal for capturing expansive scenes, such as landscapes, architecture, and interiors where space constraints limit your distance from the subject. However, wide-angle lenses can distort faces when used for portraits due to the proximity required.

These lenses emphasize the scale and distance between foreground and background elements, making close objects appear larger and distant ones smaller.

Ultrawide or “fisheye” lenses, with focal lengths of 16mm or shorter and a 180° field of view, offer extreme distortion effects.

A telephoto lens allows you to photograph a distant subject or magnify the subject within our image. Even though it enables us to capture elements far from us, this doesn’t mean the effect is the same as approaching the subject. This is due to the different planes within the frame appearing closer to each other (a phenomenon known as compression) compared to reality and how they would appear when photographed up close with a wide-angle or standard lens.

A telephoto lens has a longer focal length compared to standard lenses, so any lens with a focal length greater than 50mm is considered a telephoto. Telephoto lenses can be divided into three subcategories:

• Medium Telephoto: 50mm to 100mm.
• Telephoto: 100mm to 300mm.
• Super Telephoto: over 300mm.

Medium telephoto lenses (70mm-85mm) are popular for portraits, while super telephoto lenses (300mm+) are ideal for sports photography.

In the photo above, the Strait of Messina is captured with a wide-angle lens. In the distance, highlighted in red, you can see the Calabrian Pylon and the town of Scilla. Right after taking this shot, I switched to a telephoto lens to capture the results shown below.

The Calabrian Pylon was approximately 3 km away from my position, but thanks to the telephoto lens, it appears as if it were just a few steps away.

I captured this photo from a distance of 5.5 km, yet the compression effect of the telephoto lens makes it seem as though you could swim across that narrow strip of sea in just a few strokes.

Many people mistakenly believe that changing the focal length alters the perspective. In reality, the perspective remains the same if the viewpoint and the subject remain fixed; it only changes when you move your shooting position. What does change, however, is the perspective rendition: wide-angle lenses tend to exaggerate vanishing points, enhancing the sense of space and depth, while telephoto lenses compress the scene, making subjects appear much closer to one another.

As a result, the perceived perspective in photos varies depending on the lens used. The relationship between objects, or the apparent distance between them, shifts according to the focal length.

The chess pawns are equally spaced in both photos, each positioned three squares apart. When photographed with a telephoto lens, they appear closer together, whereas a wide-angle lens makes them look much farther apart.

Image stabilization can be implemented either in the lens or on the camera sensor. Lens-based stabilization uses a system of movable lens elements that are electronically controlled to counteract hand vibrations by moving in the opposite direction, effectively neutralizing the shake. Sensor-based stabilization works similarly, but instead of moving the lens elements, the sensor itself shifts to compensate for movement.

At first glance, an image-stabilized lens seems like the superior option, and in many cases, it is. However, the downside is that stabilization increases the lens’s cost, so if you’re on a tight budget, you might consider opting for a non-stabilized lens.

Each manufacturer uses its own acronym to denote their stabilization technology:

• Nikon: VR (Vibration Reduction)
• Canon: IS (Image Stabilization)
• Panasonic: O.I.S. (Optical Image Stabilizer)
• Tamron: VC (Vibration Compensation)
• Sigma: OS (Optical Stabilizer)

When using a camera on a tripod, it’s advisable to deactivate the stabilization system, as it can cause a phenomenon known as a “feedback loop.” In this scenario, the stabilization mechanism detects its own minute movements and tries to compensate, resulting in unwanted micro-movements in the image. While modern cameras are often equipped with an auto-off function to prevent this issue, it’s still safer to switch off stabilization manually when the camera is mounted on a tripod.

There’s a common misconception that stabilization reduces a lens’s sharpness, but this is not true. Although stabilized lenses feature a more complex optical design, advancements in technology have ensured that these lenses can be just as sharp, if not sharper, than their non-stabilized counterparts.

Stabilization is generally considered essential for telephoto lenses, as the longer the focal length, the more susceptible the lens is to hand-induced vibrations that cause blur. However, this assumption isn’t entirely accurate; having stabilization on a wide-angle lens allows for handheld shooting at very slow shutter speeds. For instance, with my Panasonic Lumix G9, I can capture landscapes and architectural scenes at night using shutter speeds between 1/10s and 1/20s without any noticeable micro-movements—something that was almost impossible without a tripod before this technology became widely available

Prime lenses have a fixed focal length, meaning you need to physically move closer or farther away to adjust the framing of your subject.

On the other hand, zoom lenses are designed to offer a range of focal lengths in a single lens, allowing you to adjust your composition without moving.

Prime lenses generally deliver superior optical quality compared to zoom lenses. This is because zoom lenses, especially those with a wide focal range, often involve optical compromises. For example, an 18-200mm lens covers a broad focal range but sacrifices more optical quality than a more modest 18-55mm or 55-200mm lens. Using two separate lenses instead of one with the same combined range typically yields better image quality. It comes down to a choice: do you value versatility or quality? The answer depends on the results you’re aiming to achieve.

An illustrative example was shared on the now-closed fotografare.com forum by a user named Attilio:

Building a car that reaches 200 km/h is not hard; even a modest car with a lively engine can do it. Making a vehicle that performs well off-road isn’t particularly difficult either; a Panda 4×4 handles it nicely. Designing a car with ample cargo space is straightforward; a station wagon can carry a lot. But imagine creating a vehicle that can hit 200 km/h, excel off-road, and haul as much as a station wagon. You’d end up with a large, expensive SUV. Now try building that SUV on a Panda’s budget, and the quality inevitably suffers.

This analogy also applies to lenses, which is why I avoid zoom lenses with excessively wide focal ranges.

Advantages of prime lenses over zoom lenses:

• Affordability of fast primes: Bright prime lenses are generally much cheaper than their zoom counterparts. Affordable prime lenses with apertures wider than f/2.8 are common, while zoom lenses with similar apertures are usually costly. For instance, the Nikon 35mm f/1.8 (prime) costs around €150, compared to €2,000 for the Nikon 24-70mm f/2.8 (zoom).
• Sharper optics: Prime lenses often provide superior sharpness since they have fewer moving parts and are optimized for a single focal length.
• Better control of aberrations and distortions: Zoom lenses, particularly at wide angles, are prone to barrel distortion. While performance differences between primes and zooms are less pronounced at longer focal lengths, primes generally maintain better control.
• Lightweight and compact: Prime lenses are typically smaller and lighter than zoom lenses, making them easier to carry and handle.

Disadvantages of prime lenses compared to zoom lenses:

• Less versatile: To change your focal length, you need to swap lenses on your camera, which can be time-consuming.

To overcome the versatility issue when using primes, I often mount a wide-angle lens on one camera and a medium telephoto on another. Keeping both cameras readily accessible allows me to switch between wide-angle and telephoto shots quickly without having to change lenses.

A macro lens is specifically designed to capture exceptionally sharp images of subjects at close range. It’s commonly used for photographing flowers, insects, products, and similar subjects.

Macro lenses are capable of achieving a reproduction ratio of 1:1 or greater, meaning the size of the subject on the camera sensor is the same as or larger than its actual size. These lenses typically have a very short minimum focusing distance—often about half of what is possible with a standard lens—though this distance can vary depending on the specific lens model.

Macro lenses are utilized differently in macro photography based on their focal lengths:

• 45mm to 65mm: Ideal for photographing products and small objects.
• 90mm to 105mm: Suited for capturing insects, flowers, and small objects from a comfortable working distance.
• 150mm to 200mm: Best for photographing insects and small animals when maintaining a greater distance is necessary.

Tilt-shift lenses are unique and often quite expensive. By loosening a screw, you can shift the lens, allowing the front element to move vertically or laterally relative to the optical axis.

These lenses are primarily used in architectural photography. For example, when photographing a building with a standard lens, tilting the camera upwards often results in converging vertical lines, creating a distorted perspective. A tilt-shift lens allows you to keep the camera level while shifting the lens, resulting in a perfectly corrected perspective without converging lines.

However, it’s important to note that this lens doesn’t always produce the most artistically pleasing results, as sometimes converging lines can add visual appeal. Tilt-shift lenses are specifically designed for professional architectural photography and for landscape shots that aim to be as true to reality as possible.

Tilt-shift lenses are also excellent for creating seamless panoramic photos without the need for a panoramic head, which helps avoid parallax and alignment issues. To create a panorama, you can simply take a shifted shot to the left, a center shot, and a shifted shot to the right, then stitch the images together in post-production.

Another notable feature of these lenses is the “tilt” function, which allows control over the depth of field by tilting the optical axis relative to the focal plane. This enables selective focus, letting you precisely control which parts of the image are sharp, making it perfect for directing attention to specific areas of your shot.