Photographers often talk about using “normal” lenses for their work. What they are referring to is a lens that mimics the field of view of human vision. In general, most photographers agree that a focal length around 50mm on a full-frame camera is regarded as a normal lens.
So, what exactly is a normal lens? The standard litmus test is a lens that renders a printed photograph of a scene held at arm’s length that matches the real-world perspective when viewed with one eye. Over the years, photographers have argued back and forth about the correct focal length, and it generally varies between 40mm and 60mm for a full-frame camera.
The truth is that the answer lies somewhere around 50mm for a full-frame (1.5″ or 35mm) sensor. This focal length changes depending on what sensor or film size you use. For example, a large format 8×10 film camera requires a 300mm lens to appear normal while a cellphone camera requires a 4mm lens to appear normal. Here are some normal focal lengths for various imaging formats:
- 150mm focal length for 4×5 large format
- 75mm focal length for 6×4.5 medium format
- 50mm focal length for full-frame sensor camera
- 35mm focal length for APS-C sensor camera
- 25mm to 30mm focal length for half-frame sensor camera
Varieties of 50mm lenses
50mm lenses are extremely popular and are available in a wide variety of options. Within a brand, lens manufacturers frequently offer at least three options for 50mm lenses, with each having varying different maximum apertures and focusing technology. For example, Nikon currently offers seven 50mm lenses for DSLRs, including:
- 50mm f/1.2 manual focus
- 50mm f/1.4 AF-D
- 50mm f/1.4 AF-S
- 50mm f/1.4 manual focus
- 50mm f/1.8 AF-D
- 50mm f/1.8 AF-S
- 50mm f/1.8 AF-S Special Edition
Sony, Canon, Sigma, Tamron, Tokina, Zeiss and Leica all offer a plethora of 50mm prime lenses to choose from, making the 50mm normal lens one of the most popular in the world.
Advantages of a normal lens
There are some clear advantages to owning a normal lens.
50mm lenses typically cost between $150 and $400, making them some of the most affordable, professional quality lenses available. In fact, one of my favorite lenses is the Nikon 50mm f/1.8 AF-D. It is an older lens, but you can still find it on sale for around $110 brand new. On the used market, you can frequently find them for under $80. Leica lenses are the outlier here, with some of their m-mount 50mm lenses costing many thousands of dollars each.
The large maximum aperture of 50mm prime lenses is one of the most important reasons to buy one. These lenses often come with maximum apertures of f/1.2, f/1.4 or f/1.8. The result is being able to shoot in very low light while still using reasonable shutter speeds and ISOs.
Excellent depth of field control
The wide aperture allows photographers to separate the subject from the background by using a narrow depth of field. This creates an image where the subject is in focus but the background is blurry. A 50mm prime makes this creative compositional choice creative very easy to accomplish. At the same time, the photographer can choose a smaller aperture like f/11 or f/16 to keep the background in focus.
One of my favorite reasons to use a 50mm lens is they are small and lightweight. When I mount one on a larger DSLR or mirrorless camera body, the setup seems downright tiny in comparison to my larger f/2.8 zoom lenses. For this reason, 50mm lenses are great for street and travel photography.
Disadvantages and challenges of using a normal lens
Using a normal prime lens does have a few disadvantages and challenges.
No zoom functionality
Obviously, shooting with a 50mm prime lens means that you won’t be able to change focal lengths while shooting. This can make it difficult if you are unable to change your physical position. However, if you can move around, then you’ll have to change your framing and composition by repositioning the camera’s position.
Critical focus when wide open
If shooting your lens at f/1.8 or f/1.4, the depth of field is very narrow. Sometimes, depth of field is just a few millimeters. Therefore, if your subject moves at all during your image, their eyes will be out of focus or the flower will be out of focus. You have to be extremely diligent when shooting wide open.
Do you own a “normal” lens for your camera? If so, what you like or dislike about it? Let me know in the comments below.