Photo: Neon Trees by giovanni gallucci

A common challenge for beginning photographers is understanding focal length. Shortly after buying your new DSLR or mirrorless camera you might find yourself searching for new ways to make your photos stand out. For many, this leads to a search for a lens, or lenses which will help you create your vision long before you have a clear understanding of what differentiates one kind of lens from another. Don’t worry, you’re among friends here…we’ve all been through this.

First, find a product specialist to work with.

If you are just entering the world of digital photography, it is likely that while searching for the perfect photo, you have purchased all kinds of photography products without actually having the benefit of using them or knowing how to maximize their potential. I’ve been in this boat as well. Lucky for me I’ve had the benefit of the knowledgeable, no-nonesense staff at Competitive Cameras in Dallas, TX.

After shooting as an amateur for 15 years, I went to them to purchase my first pro camera kit. They asked me what I was shooting and consistently directed me to the right products and explained why they recommended the products they recommended to me. At that time I was already a loyal Canon shooter so, taking that into account I built a shot-kit of 5D’s and 7D’s along with several L-Series lenses that rocked my socks off. Those were easy sells, but in a couple situations, as the staff got to know me and my work, they steered me to a couple Tokina lenses, based solely on my individual needs, saving me hundreds of dollars. This kind of partnership is invaluable for a shooter.

Along with the product knowledge, the folks at Competitive Cameras were generous with their knowledge. This is critical when you are deciding on how to spend your hard-earned money on lenses which will set you back anywhere from several hundred to several thousand dollars a pop. One of the best lessons I learned from the staff was understanding how focal length works in lenses. With this knowledge I was able to discern when I could use the lenses I already owned for a shoot and when I actually needed to borrow, rent, or purchase a new lens for a job.

In this article I will explain the difference between the focal length and angle of view and the differences between different types of targets according to their focal length. I’ll recommend which focal length to use in different situations so that you can get the most out of the lenses you have today.

What is the focal length of a lens?

Since we are buried in so many choices today when it comes to using different lenses, I’m going to focus on explaining in detail one of the fundamentals of photography: focal length. If you are completely unfamiliar with this concept, here is a simple explanation so you can get the most out of this article: The distance between the center of a lens or curved mirror and its focus is the focal length.

The focal length of a lens is the distance, in millimeters, between the sensor (focal plane) and the optical center of the lens. What is the optical center? I don’t want to get too technical here, the focal length is not measured from the sensor to the front lens of the lens, but is the point where light rays intersect in this and are directed towards the sensor.

Photo Credit: The Definitive Lens Buyers Guide

Depending on the size of the sensor in your camera, the focal length may vary. For example, a 50 mm lens mounted on a full-frame camera DSLR like the Canon 5D Mk III provides approximately the same field of view as a 32 mm lens mounted on an APS-C mirrors camera like the Fujifilm X-T1. Don’t get too hung up on this though, I’ll explain later how to calculate the real or effective focal length.

So you might now know the technical definition of “focal length” but that’s not enough. You need to understand how to put this knowledge to use in a practical sense when composing your shots.

Effective Focal Length

The focal length of a lens, no matter what the make or model of lens, is used as a reference to the size of a full frame (35mm) sensor in a camera. Why is this important? Because the “effective focal length” of the lens you are using changes according to the size of your camera’s sensor.

If you have a camera with an APS-C sensor, like the Canon 7D Mk II, it’s is smaller than a full frame sensor on a Canon 5D Mk III. A 50mm lens on a 5D Mk III is roughly equivalent to a 75mm if you use a Canon 7D Mk II.

Why? The focal length of a lens depends on the size of the chamber in which the sensor is placed. The APS-C sensor is smaller than the full frame standard. So to determine the effective focal length, you must multiply the original distance by a multiplication factor. This factor is roughly 1.5 when moving from APS-C to full frame.

As a preemptive strike to head off the photo tech-nerds, I understand that different brands have different crop factors – as their sensor sizes are different sizes. We’re trying to keep it simple here.

How this multiplication factor calculated? It’s simple:

Full frame width (35 mm) sensor / Width of your camera sensor = Effective Focal Length.

If you do not know which is the width of your camera sensor, you can consult the manufacturer page thereof. Usually expressed as follows: 23.6mm x 15.6mm. The first portion (23.6mm) is the width of the sensor.

How does this affect your photographs?

We’ll use the Fujifilm X100T for this example. This camera has a lens with a focal length of 23mm and I love to take it on trips to use for editorial, street, and landscape photography. But the X100T has an APS-C sensor: the effective distance is not 23mm but 34mm (factor 1.48).

Result: The target is not as angular as a photographer used to 35mm or full frame digital cameras would expect and the viewing angle (I’ll explain this later) only allows me to capture a portion of the scene itself than the advertised focal length printed on the lens itself.

Prime or Zoom?

Prime lenses do not allow varying the focal length. Varifocal lenses (or zoom lenses) can cover larger distances by moving the lens position relative to the sensor in the camera’s chamber, varying the focal length.

Should you choose prime lenses or zoom lenses? Yes.

Each type of lens, whether prime or zoom, has advantages and disadvantages. Choosing the “right” kind of lens for you will depend on your taste and needs as a photographer. Here are a few things to consider when deciding which type of lens you should use. Again, photo tech-nerds, these are generalizations for the sake of simplicity.

Prime Lenses

Advantages:

Superior optical quality resulting in sharper pictures.

Constructed with fewer moving parts and are therefore more resilient and robust.

Optimized for its specific focal length and produces fewer aberrations.

Allows more light into the lens – lets you take better shots in low light with a more shallow depth of field when working with large apertures (f / 1.4, f / 1.8, f / 2.8).

Many of them are less expensive than their zoom-enabled counterparts.

Disadvantages:

Less versatile since its focal is fixed.

For certain types of photographs, lack of versatility can really be a problem.



Photo Credit: Fujifilm

Zoom Lenses

Advantages:

They are very versatile, comfortable and allow you to adjust the frame without moving.

Indispensable for certain types of photographs in which you require longer focal range, such as music or sports photography.

They have a large number of focal ranges so you avoid constantly swapping lens on your camera.

Disadvantages:

They are usually much more expensive than prime lenses, especially those who need multiple focal lengths.

Since they have more moving parts, they are more fragile and much more susceptible to malfunction when shooting in the field.

Weight and size of the typical zoom is considerably larger.

Viewing Angle

The focal length is not the only element that must be taken into account when setting up your shot. You should also pay attention to the angle of view. This will help you understand the different possibilities and limitations of selecting different lenses with your camera’s sensor size.

The viewing angle is akin to the “portion of the scene” that the lens can capture. Viewing angle is measured in degrees. The more angular your lens is, the greater portion of the scene you can capture with your lens. The more you zoom into a scene, the lower portion of the image that will be captured in a photo.

For example, a lens with an effective focal length of 300mm provides a viewing angle of about 8.15 degrees. When you use one, you fill the sensor with a much smaller portion of the scene. This is why you perceive being closer to your target. By contrast, if you were using an 18mm (76 degree angle) lens the same portion of the scene would occupy a much smaller size frame, making you feel like you are much farther away from the target of your shot.

Lenses are categorized and marketed based upon their focal length. However the really important measure of a lens is the angle of view. The typical photographer’s mind envisions a shot based upon the angle of view, not the focal length. Of course, every viewing angle corresponds to a specific focal length. Speaking of one is like using a synonym for the other. However, having a command of your craft and developing the skill to realize your vision on your final work requires that you understand how these work together.

The chart below demonstrates the relationship between the angle of view and focal length of a lens:

Photo Credit: Panasonic

If you want to see how this works in practice but do not have enough lenses to try it yourself, take a look at the lens simulator that Nikon has made available to perform all the tests you want, free of charge.

Classification Of Lenses Via Viewing Angle

Super wide angle: these create a “fisheye” effect and can cover a viewing angle of 180 degrees or more. These are typically in the 8mm to 12mm range.

Wide Angle: Lenses covering a viewing angle of between 110 and 60 degrees, representing an effective focal length of 10mm to about 25mm.

Standard/Medium: Lenses covering a viewing angle of 60 to 25 degrees, representing an effective focal length of 25mm to about 65mm.

Telephoto: Lenses which cover a viewing angle of 25 to 10 degrees, which corresponds to a focal length of 65mm to 160mm.

Super telephoto: Lenses which cover a viewing angle of 10 to 1 degrees, ie, 160mm to 600mm focal length.

Photo Credit: Digital Camera World

Now that you understand the fundamental technical aspects it will respect the lenses, it is time to see what kind of photography is ideal for each of these.

What Are You Shooting?

While you can perform almost any type of photography for any purpose with any lens, each lens is designed for a particular use. While you can use a wide-angle lens for a portrait, you’ll get better results if you use a telephoto 85mm to blur the background and make your subject “pop” off the portrait.

If you want to take full advantage of your current lenses and/or are about to buy a new lens, you need to have a clear understanding of which lens focal length will deliver the best results from each of these general situations.

There are different types of focal lengths that you may find useful for close-up photography or macro photography. At the end of the article we will discuss these as well.

Landscape/Architectural/Cityscapes

In this type of shot you will need to capture the largest portion of the scene as possible so as to transport the viewer into the picture.

The more space you want to show in your photos, the wider viewing angle you need. Therefore, the lens you use should have a shorter focal length. A wide-angle lens (focal lengths less than 25mm on APS-C) is the recommended option.

Photo: Beaver Creek, Colorado by giovanni gallucci

Event/Street Photography

The focal type that you will use if you plan to venture into the world of wedding photography, event photography, portrait work, street photography, etc. will depend on the type of shoots you book and the locations that you shoot in.

Wedding and event photography is fast moving and complex. You need a lens with variable focal distance that allows you greater versatility than when you are making portraits in a studio where you can take the time to change lenses according to the current the. One option if you prefer using prime lenses would be to carry two camera bodies with different focal length lenses on each camera. I typically shoot documentary music and event photography outdoors. Carrying a heavy backpack with several lenses in it and changing lenses outside in dusty and windy conditions is not ideal. So I carry at lest two cameras with me on shoots. One will typically have a wide/standard angle focal length lens on it (23mm) and the other will have a tele focal length on it (80mm to 200mm).

Photo: Buyer 10 at the Barefoot at The Belmont event by giovanni gallucci

In all these types of photography, it’s not easy when you’re a beginner to choose between one or the other focal length, as each have their advantages and disadvantages. What you should be clear on is what kind of photos you expect to take, which angle (or focal length) will need to use to achieve this. Don’t be too hard on yourself at first. Experiment. In time, your aching back and your developing style will help you narrow down which focal lengths with best for you.

Action/Indoor Sports Photography

There are some storytelling scenarios in action and sports photography which require wide angle shots of stadiums or landscapes in order to set the scene of the story you are trying to tell within a series of photographs. However, in this type of photography it is typically not necessary to produce a large number of panoramic shots of the entire environment. You typically need to focus the viewer’s attention at a specific event within the larger context of what is happening.

You are usually focused on getting up close to where the action is taking place. It’s ideal for this type of photography to have a telephoto lens that allows you to create the perception that you are near the action while shooting from a distance.

Photo: Dallas Mavericks Dancers by giovanni gallucci

While fixed focal length lenses provide superior results when compared to zoom lenses, the latter is much more versatile because you can shoot using either distance according to the situation you are in. Given both types of lenses, it’s better to get a shot than to miss a shot altogether because you are fumbling with lenses. A 70-200mm or 70-300mm lens is ideal in a sports situation. But don’t take this analogy too far. Stay away from super-zoom lenses like the 18mm-200mm lenses not eh market. While you can avoid having to change lens all the time, your photos will be grainier and you will will sacrifice too much quality for the convenience.

Adventure/Outdoor Sports Photography

Sports photography (soccer, football, auto racing, etc.) requires lenses with a much longer focal length. When shooting a hang glider in flight, a soccer player scoring a goal, or a motorcycle hugging a curve, the distance at which you can effectively capture your subject is considerable.

I recommend a focal length from 100mm up to 600mm – depending on your budget. High quality lenses above 200mm can be quite expensive. Keep in mind that if your camera’s sensor size is less than full frame, ie. APS-C, a 200mm lens has an effective focal length of 300mm on average. Remember to multiply by the factor (1.5-ish for Nikon, Canon, Pentax, Fujifilm. etc) for a lens’ effective focal length as we discussed before.

Photo: FC Dallas by giovanni gallucci

The further away you are from the subjects or objects you want to shoot the longer the focal length of your lens needs to be if you want to end up with good photos. I recommend you have a lens with about a 70mm-300mm zoom to allow greater versatility. If you can’t afford to purchase a lens like this, check out our friends at Borrowed Lenses about rental costs. You won’t be sorry. When I shoot sports, and motorsports in particular, I usually don’t have any idea how close I am going to be able to get to the action before I arrive on site during the day of the shoot. I pack a Fujinon 55mm-200mm lens with me for those situations. Also with a monopod I always end up with usable, tack sharp photos with minimal stress.

That’s the first time I mentioned a monopod in this article. I usually shoot freehand. But the greater the focal length, the greater risk you have of churning out gigs of blurry photos. So, past 60mm, I only use stabilized lenses which allow me to shoot at slower speeds and work in lower light situations. When allowable, I always use at least a monopod and in some rare situations a tripod.

Macro/Product photography

The distance to the subject when shooting macro photography is essential, but in this case you should be close enough to fill the frame with your subject. This is where macro lenses come into play.

There are all kinds of macro lenses available with different focal lengths and all can be useful depending on the type of subject or object you plan on shooting. To photograph products, for example, I use a macro 60mm focal length since it is unlikely that a tech gadget will fly away from the scene I’m shooting. However, if you are photographing a butterfly while it’s sitting on a sunflower it will be difficult to get the shot with a short focal length as you will most likely spook the subject and it will fly away.

Learn how lenses work and investigate alternatives to the name brands to be a better steward of your finances while still producing amazing photographs.

All photographers shoot with an innumerable number of purposes. You’re needs are unique. Just remember that the camera is only a tool the photographer uses to bring their vision to life. Understanding how all your equipment works will make it much easier for you to realize your vision.

One last tip. Financially, it is not always necessary to spend top dollar for a lens simply because of the brand name on it. You should also look into purchasing used lenses. eBay is your friend. Since I switched from Cannon to Fujifilm – I have purchased ALL my lenses on eBay with no issues at all, saving an average of 10% to 20% off street prices. Be sure to check the seller’s feedback, read the details on the condition of the lenses, and calculate shipping costs before bidding.