What Is Focal Length: Pro Guide To Using Camera Lenses

In photography, focal length is the distance in mm between the sensor and the point at which light rays converge to form an image.

Focal length also describes what angle of view your lens covers, which is a function of the lens design.

The focal length that’s written on the front of your lens determines what you can photograph with it, how much light it lets into the camera and where the focus point falls.

In order to get a grasp on what focal length does to your images, you need to understand two things: field of view and depth of field.

So let’s get back to basics and talk about how focal length affects your photos.
 

What Is Focal Length?

A lens’ focal length is the distance between its optical center or “film,” and the point on an image that appears to be in focus.

The lens’s focal lens is in millimeter (mm) units, with each number reflecting ten times the previous one. For instance, a lens with a focal length of 28mm is 10 times longer than one with a focal length of 2.8mm.

Larger numbers refer to lenses that are more telephoto, which means they compress the space between an object and the background and make subjects appear farther away than they really are.

Shorter numbers refer to wide-angle lenses that capture more of a scene and make it appear larger than life.

When you take pictures using a zoom lens, you’re changing the focal length while keeping the camera in the same position.

This allows you to frame different subjects without moving around while changing the relationship between the foreground and background objects. This way, they’ll look closer or farther away depending on your focal length.

For example, as you zoom in with a telephoto lens, objects in front of your subject appear closer; as you zoom out, they appear farther away. Wide-angle lenses do just the opposite.

   

How Does Focal Length Work With Camera Lenses?

Focal length is an important part of any camera lens, but it isn’t immediately obvious to everyone. It is important for photographers who want to get the most out of their cameras.

Trying to understand focal length can be a little confusing at first, especially for people who are new to photography. It is simply the distance from the main to the sensor or film plane within a camera’s lens.

Basically, it dictates how much of a scene you can fit into your frame and how close you need to be as well. A short focal length means that you can zoom in on far-away objects, while a longer focal length makes it possible for you to capture more elements in your image, even if they are closer.

The short end of the scale is 35mm and below, which allows you to capture wide shots with ease. The longer the focal length, the less able your camera is to capture a large area, but objects in the distance will appear larger.

What Does 50mm Focal Length Mean?

The focal length of a lens is the distance from the optical center of the lens to its focal point. This point is where light rays converge and are brought into focus, creating an image on a camera’s sensor.

How does this relate to different lenses? Focal length is in millimeters, and it’s an important consideration when choosing a lens for your camera.

If you’re looking to shoot portraits, you might want a lens with a very long focal length—such as 200mm or 300mm. This will allow you to capture more of the scene in front of you while still being able to focus on your subject.

If you’re shooting landscapes, you might want a wide-angle lens with a short focal length—such as 35mm or 24mm.

Here are some common focal lengths:

Wide-Angle (short) 10-15mm – these lenses have a very wide angle of view (so much so that they can be hard to handle on full-frame cameras with their large sensors!) They can be good for landscape shots or architectural photos where you want to include many features in the photo without them being too distorted. A 14-24mm lens, however, is a slightly wider angle than a 10mm.

How Does Lens Focal Length Affect The Image?

If you have been using the same prime lenses for your photography, then you probably are wondering what the fuss is all about with lens focal length.

   

There are many reasons a photographer should consider replacing their lenses, and one of those reasons is that focal length affects the image.

If you were taking photos of a landscape, then a wide-angle lens would give you a very different view than a telephoto lens would. A person’s face is going to appear much larger in an image taken with a long focal length than it will in an image taken with a wide-angle focal length.

This is because there is less distance between the subject and the camera when using a long focal length lens. Details in your photos can change significantly between different focal lengths.

If you want to include more details in your photos, then you should use longer focal lengths. To focus on one particular subject, you can either use a longer or shorter focal length, depending on what type of photo you want to take.

What Is The Best Camera Focal Length?

A photographer has many decisions to make when it comes to camera settings. One of the most important decisions is choosing the right camera focal length.

By definition, a focal length is the distance of a lens from its line of focus; or in layman’s terms, how zoomed in or zoomed out your image will be when you take a photograph.

A wide-angle lens has a short focal length (a wide-angle lens also has a shorter depth of field).

A telephoto lens has a long focal length (a telephoto lens also has a deeper depth of field).

   

The two major types of photography are close-ups and wide-angle photography. For close-up work (commonly called “macro photography”), you need at least an 80mm focal length on your camera. It is possible to get closer with an even longer focal length, but only if you use specialized equipment like bellows and extension tubes. 

So, you’re asking: what is the best camera focal length?

Wide-angle shots are best for capturing environmental scenes and large objects. Telephoto lenses, however, are good for close-ups of small objects, such as a bird in flight, flowers, or insects.

How Far Does A 600mm Lens Zoom?

Many photographers are searching for a telephoto lens that is at a fair price, especially if they want to take pictures of wildlife. Many photographers already own one of these lenses and want to extend the capabilities of their equipment.

With this type of lens, the photographer can capture images that impact the viewer, giving the viewer a feeling like they are part of it.

The telephoto lenses are also good for zooming in on distant objects such as wildlife and birds while they are flying or for other types of action shots. The telephoto lens has been around since the 1800s when it was called a “telescope”.

Telescope lenses were quite expensive and heavy, but by the 1960s, the cost went down to make them affordable for amateur photographers. Today, we have many types of telephoto lenses available for any budget.

The Canon EF 600mm f/4L IS II USM Lens is an excellent example of what today’s photographer has to work with when using a lens that gives you 600mm worth of zoom capability. This lens weighs 2 pounds 11 ounces and measures 10 inches long, making it easy to use.

Focal Length And Angle Of View

The focal length of a lens is its physical distance from the image plane. In 35 mm film cameras, it’s the distance between the rear nodal point of the lens and the sensor or film plane.

The angle of view is the angular extent of a scene that can be captured in an image. A wide-angle lens has a small angle of view, while a telephoto lens has a large angle of view.

A focal length is usually expressed in fractions or decimals: A zoom lens is a variable focal length (VFL) lens, meaning that its effective focal length changes as we zoom in or out. The focal lengths are given in either their longest or shortest settings.

For example, if a VFL lens gives you an angle of view of 50° at its widest setting, and 20° at its narrowest setting, it will be listed as 10-20mm f/3.5-4.5 (10mm–20mm).

The designations “wide-angle”, “normal” and “telephoto” are relative terms for lenses with specific angles of view and not absolute focal lengths.

For example, a 14mm lens is a wide-angle on an APS-C sized sensor. The focal length of your lens is one of the most crucial factors in how you see the world through a camera.

An extremely wide-angle lens will distort the image and make objects appear unnaturally close, while a telephoto lens will compress the image, making far-off things look nearer. Because of this, it is essential to research what focal length lenses are available for your camera system.

There are two major categories of focal length: wide-angle and telephoto. The exact definitions vary depending on who you talk to, but the easiest way to identify them is from their angles of view.

Here is an example:

Wide Angle Telephoto (3mm 8mm 14mm 24mm 35mm 50mm 85mm 135mm)

The wider angle lenses have a very broad field of view; longer lenses have a narrower field of view. The table below shows just one example — for full-frame 35mm cameras with equal resolution, each additional 10 mm (1 stop) of focal length will give you approximately the same viewing angle as moving back 10 feet.

How wide is “Too Wide”? One thing to keep in mind with ultra wide-angle lenses is that they can introduce distortion into your images. It can seem especially pronounced if you’re shooting straight lines.

   

Focal Length And Filmmaking

Trying to determine the right lens for your shot can be overwhelming if you don’t know what you’re looking for. So let’s break it down.

The focal length of a lens determines the magnification and angle of view. The larger the number, the greater the magnification and narrower the angle of view.

A long focal length lens (more than 100mm) makes objects appear smaller and closer to the camera than they actually are. A wide-angle lens (less than 35mm) has a narrow field of view, making objects appear larger and farther away than they actually are.

What do focal lengths mean in practice?

Wide angles give you a lot of flexibility, allowing you to capture a wider frame without moving yourself or the camera. Using this type of lens can fit many objects into your frame while also keeping them all in focus.

They’re also great for shooting indoors because they allow you to compress extensive areas into a small space.

Filmmakers use telephoto lenses for portraits and other close-up shots because these lenses compress the background and make objects appear larger than life.

They’re great for isolating subjects from their surroundings, so if you want to capture that wildlife shot.

Focal Length Examples In Cinema History

If you enjoy filmmaking and have an interest in history, then you might like this part. It’s actually quite interesting to know the full history of filming and how it has developed. So, without further ado, let’s dive into the world of focal-length examples in cinema history.

The early days of cinema, or “the silent era” was during this time that filmmakers started using lenses with smaller focal lengths, which meant the image wanted to be larger on the screen because it had a shorter focal length. This made sense, as they usually were shooting on negative film stock.

This meant that they needed to use lenses with a longer focus to ensure they were sharp enough on the screen. The most common lens used at the start of cinema was actually around 65mm to 70mm, which is roughly equivalent to a 21mm lens in full-frame 35mm format.

This lens is known as a “Long Focus” lens and was ideal for those who were shooting actualities (documentary style filmmaking). These types of movies were shot close up and personal, so it provided a good amount of focus needed for those types of shots.

   

Field Of View And Equivalent Focal Length

Field of view and equivalent focal length are two distinguishable concepts that both relate to the angle of cover that a lens provides. In this part, I will explain how they are different and how we can use them.

A Brief Introduction To Field Of View

Field of view is one way of describing how much of a scene a camera or lens sees. It is expressed in degrees, with 180° being a complete view of what is in front of you and 0° being just a tiny dot.

The field of view can be measured using a tool called an angular field calculator, which uses trigonometry to work out the exact field of view for any lens. Alternatively, this can be estimated using the “35mm equivalent” focal length method described below.

Equivalent Focal Length Method

This method works by relating the focal length of the lens to that of a 35mm (full-frame) camera, which is why it’s called ’35mm equivalent’. The actual focal length of a 35mm camera is 48 mm (in full-frame terms).

A 50 mm lens has the same angle of view as a 28 mm lens in a 35mm format. This means that if you use the 50 mm lens on your APS-C sensor DSLR, you will get roughly the same results.

Classifications Of Focal Lengths

In this section, we will discuss the different classifications of focal lengths, how they work, and how to choose the right focal length for you.

The first classification of focal length is Prime vs. Zoom.

• A prime lens does not zoom in or out. It has a fixed focal length.
• A zoom lens can change the focal length (zoom in or out).

The second classification of focal lengths is wide-angle, standard, and telephoto.

Wide-angle lenses have a short focal length (10mm-18mm). These lenses often make a large object appear small, such as a building or landscape. Standard lenses have a medium focal length (35mm-50mm). 

Portrait photographers use them to keep the subject and background sharp. Telephoto lenses have a long focal length (80mm-300mm).

We often use them for sports photography or to capture wildlife at a distance. 

The third classification of focal lengths is Ultra Wide-Angles, Super Wide-Angles, and Wide Angles.

Ultra wide-angle lenses have an angle of view higher than 90 degrees (10-16mm); super wide-angle lenses have an angle of view between 78 degrees and 90 degrees (14-24mm), and wide-angle lenses cover 78 degrees or lower (35mm or shorter).

   

Zooms vs. Prime?

For some time now, there’s been a debate stirring up in the photography community. F-stop or prime lenses, zooms or primes, crop sensor or full-frame, and so on.

My first DSLR was the Canon EOS 350D, a cropped sensor camera with a focal length multiplier of 1.6. It gave me the flexibility to carry around one lens, which could cover everything from wide-angle to short telephoto without changing lenses.

The photos I took with that camera were sharp and detailed, but I was never completely happy with the results, especially when compared to some shots taken by other photographers using a full-frame camera. In fact, it wasn’t until I bought my full-frame Canon 5D Mark III that I loved photography again.

The quality of the images from that camera was so much better than anything else I’d ever used that I couldn’t help but be impressed. So what is it about a full-frame camera which makes such an impact?

Well, simply put, it’s because it has larger image sensors.

This will give you more resolution and better image quality in low light conditions and allow you to use wider aperture lenses at lower ISO settings (which means less noise).