Focal Lengths, Part II: What Exactly Is Normal? – Capturing the World with Normal Lenses

A few weeks ago I started a short series of posts on the different focal lengths of lenses and what that means to photographers. In Part I, I talked about wide and ultra-wide angle lenses which consist of a short focal length. As such, these lenses produce angles of view greater than that of human vision. For photographers these lenses allow you to capture more of a scene from a shorter distance, but more importantly have a greater depth of field and produce a feeling a space between objects closer to the lens compared to those which are further away. In this week’s post, I am going to focus on lenses that fall in the normal range. For reference I am reproducing the same table of focal lengths from Part I.

Lens Range	Focal Length (35 mm frame)	Focal Length (1.5x Crop Sensor)
Ultra-Wide Angle	< 20 mm	< 14mm
Wide Angle	20mm - 35mm	14mm – 24mm
Normal	35mm – 70mm	24mm - 47mm
Short Telephoto	70mm – 105mm	47mm - 70mm
Telephoto	105mm – 300mm	70mm – 200mm
Super Telephoto	> 300mm	> 200mm

As I defined in the last post on focal lengths, a normal lens, as accepted by photographers and lens manufacturers, is a lens with a focal length around that of 50mm on a 35mm frame. Normal lenses ultimately range from about 35mm up to around 75mm. The notable feature is that lenses in this range produce images approximate to human vision in spatial relationships as well as having an angle of view similar to the human eye. In actuality the range is not defined by human vision but actually by the relationship to the diagonal measurement of the film or digital frame. On a 35mm frame, the diagonal measurement is around 43-44mm, but for ease of definition is was agreed to make the standard length 50 mm on this frame size. It should be also noted that 50mm is relative to a 35mm frame size. For a 1.5x crop sensor, a focal length of 35mm is approximately equivalent to 50mm (actually 52.5mm, but who’s counting).

Normal lenses are pretty straightforward tools for a photographer and as such this post will be more brief than most of my others. As this focal length approximates human vision it can be both one of the easiest lens to use, and also one of the more challenging at the same time. What do I mean by that? As normal lenses approximates human vision, it can be easy for the photographer to look at a scene and approximate what that scene may look like in the photo by just using his/her eyes. The distance between foreground and background objects are “normal” rather than exaggerated when using a wide-angle lens or a telephoto lens. There is little distortion caused by the lens as well. Wide-angle lenses can exaggerated features of a subject by spacing them out, or making closer features appear larger than those further away. On the flipside, telephoto lenses tend to compress or flatten features. Normal lenses do neither and reproduce spatial relations and size as we are used to seeing. As a result a photographer can just look around and see what he will see (approximately) through the lens.

So this is why normal lenses can be easier to use, but I also said this can make them more challenging. What I mean by that is that a photographer, if going for an artistic approach, has to work differently to make a interesting photograph.  No matter what lens or camera you are using you need to work on composition, subject matter, lighting, etc. However with a normal lens, you have to work on your subject matter using the same approximate view that every observer of the same scene would have and so therefore does not immediately present an added level of interest. For example, if you are 20 feet away from a tree with a camera with  normal lens and stake a picture, you will accurately reproduce and image of the tree, but it will look the same way it would like you just stood there and looked with your eyes. If you used a wide angle lens to take the same shot from the same position, it may make the tree look bigger than it is as compared to the background the photo with the normal lens. If you used a telephoto lens, you may capture some small details on the tree that aren't seen well by the normal lens. Both the wide angle and telephoto are different than what an observer sees and so can add a level of intrigue. You may think that this is a disadvantage of lenses of normal focal length, and my post should not be read that way. It is merely a difference, but one that should be recognized. On the flip side, the normal angle of view also means it reproduces the scene more accurately when compared to human vision. Neither a wide angle or telephoto lens can do that. Again, just a difference. However, because it is reproducing the scene with a similar view to all other observers, the emphasis is put on what and how you capture the subject matter rather than the effect the different angle of view and the effect on spatial relationships that other focal length have. This can be done in numerous ways, that I won’t get into in this post, and is really what makes up personal style of a photographer. But that being said, using a normal lens means you can’t rely on the altered view of the world from using longer and shorter focal lengths to add a level of artistic appeal of your photo. Does this mean that shots taken with normal lenses are any less artistic than those of other focal lengths? Again, absolutely not. Some of the most wonderful photographs ever taken were taken with normal lenses. Henri Cartier-Bresson was famous for only using a 50mm lens for his photographs. It just means that you have to see the beauty and art in things that most observers overlook and then capture it in a way to display that beauty.

Normal lenses tend to be fast lenses, and cheaper than fast lenses of shorter and longer focal lengths. For those not familiar with the term, a fast lens is one with a large maximum aperture (f-number smaller than 2.8). As they have a larger opening to let in light a shorter, or faster, shutter speed can be used. This has three advantages. First off, the faster shutter speed can freeze the action better than a slower one. With a wide maximum aperture a faster shutter speed can be used which can freeze faster objects. The second advantage is low light performance. Fast lenses can produce sharp images in lighting situations where slower lenses will cause blur, particularly when shooting subjects that can move, or when shooting hand-held. The third advantage is the ability to produce an incredibly shallow depth of field. This can be used for both practical and artistic reasons, by drawing focus to the subject by blurring out the foreground and background subjects. A lens of f/2.8 already has a pretty shallow depth of field so you can imagine how shallow it is with a lens with an f/1.4 maximum aperture. This shallow depth of field is often used in portraiture. In the world of the 35mm frame, a 50mm lens is a little short for portraiture. Often for portraits you want a shallow depth of field and a slight telephoto to compress the features of the human subject while still looking natural. This makes for a more flattering look. However, using a cropped sensor DSLR, a 50mm lens is equivalent to a 75mm lens. Even better, a 60mm lens is equivalent to 90mm lens. Bother are great length for portraits (most pros agree that 85-105mm is the ideal range for portraits but 75mm is not that far off and still works well).

I mentioned they were cheaper than fast lenses of wider or longer focal lengths. In general this is true. The normal lens is technically easier to engineer than lenses with angle of view greater or narrower than normal. As such they tend to have fewer glass elements, are lighter and have a simpler design. This ease of engineering means that they can generally be had for a lower price. For example, Nikon’s fast 50mm f/1.4 prime is approximately $350. For comparison, an 85mm f/1.4 prime is about $600 and the same goes for a fast 28mm lens. Even better, Nikon, and most manufacturers make a 50mm f/1.8 which is only 2/3rds of a stop slower and can be had for a mere $125. These lenses still tend to be super sharp, and I think that every photographer should have one in their camera bag. Most major manufacturers usually make a version for cropped sensor cameras (typically a fast 35mm lens) as well as full frame sensor cameras (note that the 50mm will still work on a cropped sensor just fine, but will be equivalent to a 75mm lens).

As you can see, normal lenses are straightforward, yet powerful tools for the photographer. If you could only own one lens for your whole photographic career, it should be a fast, normal prime lens. It can accurately reproduce the world around you. If you can own two or more lenses for you career, one of them should still be a fast, normal prime lens. The simplicity of the lens, and advantages described above make it easy to go out and capture the world.