Prime lenses, also known as fixed-focal-length lenses, tend to have bigger maximum apertures than zoom lenses. This makes them great for creating bokeh as well as shooting at night or freezing action with a fast shutter speed. Let’s explore how their unique features can benefit our images.

EOS R50 + RF35mm f/1.4L VCM @ 35mm (56mm equivalent), f/2.8

 

Get great bokeh easily

Benefits
- Large maximum aperture, great for creating bokeh.
- Enable a faster shutter speed in low light.
- Tend to be small, lightweight and therefore very portable.

Weaknesses
- Need to change lens to change focal length.
- Cannot zoom to change the field of view.

 

What is a prime lens?

Prime lenses are also known as single focal length lenses or fixed focal length lenses. As those names suggest, they have only one focal length, so it is not possible to zoom in or out to change your angle of view.

While that may sound inconvenient, photographers love them for various reasons:

i) Beautiful bokeh
Prime lenses usually have wider maximum apertures than zoom lenses, like f/1.2, f/1.4, and f/1.8, which easily creates beautiful background bokeh/shallow focus effects.

ii) Good for low light
Being able to use a smaller f-number (wider aperture) in dim or dark conditions means you have more flexibility with shutter speed and ISO speed settings. You can use a faster shutter speed to freeze action or avoid blurring from camera shake, or set a lower ISO speed so that the image is less grainy.

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Recap the relationship between aperture, shutter speed, and ISO speed in:
Camera Basics #3: Exposure
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iii) Often smaller, lighter, and more portable than a zoom lens
Compared to zoom lenses, prime lenses have a simpler lens construction. This makes many of them smaller, lighter and more portable than zoom lenses that cover the same focal length. 

iv) Trains your composition skills
Using a prime lens changes the way you shoot: you’re forced to move around to find the best composition instead of simply turning the zoom ring. It’s a workout, but it also trains your composition skills and encourages you to get creative!

Also see:
Ideas for Self-Imposed Shooting Restrictions to Help You Out of that Creative Rut!
Prime Lens or Zoom Lens: Which Should I Buy?

 

Key concept (1): Types of prime lenses

Prime lenses fall into four main categories.

Wide-angle lenses

These can capture a wide area of a scene. They have a full frame-equivalent focal length of 35mm or less.

Ultra-wide-angle lenses are a special kind of wide-angle lens with a full frame-equivalent focal length shorter than 24mm.

Standard and mid-telephoto lenses

Standard (also known as “normal”) prime lenses have a full-frame equivalent focal length of around 40 to 60mm. They give a perspective close to that of the naked eye. The most common standard lens is the 50mm f/1.8 “nifty fifty” lens.

Mid-telephoto prime lenses are prime lenses that give a full frame-equivalent focal length of 70 to 135mm. Some classic focal lengths are 85mm, 100mm, and 135mm. These lenses are popular for portraiture and product photography because they capture shapes faithfully with little to no visible distortion.

Telephoto lenses and super telephoto lenses

These can capture faraway objects close-up. Super telephoto prime lenses have a full frame-equivalent focal length of 400mm or more.

Macro lenses

These can capture close-up images of tiny subjects.

 

Examples of Canon RF prime lenses

2 ultra wide-angle lens and 2 wide-angle lenses
(1) RF16mm f/2.8 STM
(2) RF24mm f/1.8L Macro IS STM
(3) RF28mm f/2.8 STM
(4) RF35mm f/1.4L VCM

Also see:
Lens Review: RF28mm f/2.8 STM vs. RF35mm f/1.8 Macro IS STM in Travel and Street

1 standard lens and 2 medium telephoto lenses
(1) RF50mm f/1.8 STM
(2) RF85mm f/2 Macro IS STM
(3) RF135mm f/1.8L IS USM

Two super telephoto prime lenses
(1) RF600mm f/11 IS STM
(2) RF600mm f/4L IS USM

Macro lenses
(1) RF24mm f/1.8 Macro IS STM
(2) RF35mm f/1.8 Macro IS STM
(3) RF85mm f/2 Macro IS STM
(4) RF100mm f/2.8L Macro IS USM

 

Key concept (2): Prime lenses, zoom lenses and the difference in bokeh effect

Prime lenses tend to be better for blurring out the background (creating bokeh) compared to most consumer variable aperture zoom lenses at the same focal length. The examples below were shot at 35mm on an APS-C camera (56mm full frame-equivalent focal length). The maximum aperture on the prime lens was f/1.4; on the zoom lens it was f/5.6. Note how this difference has significance on the background blurring (bokeh).

 

Key concept (3): More f-stop settings to choose from

Prime lenses provide a wider range of usable f-numbers compared to a variable aperture zoom lens at the same focal length. For example, at 35mm, the maximum aperture is f/1.4 on the RF35mm f/1.4L VCM  but f/5.6 on the RF-S15-45mm f/4.5-6.3 IS STM. More f-stop settings, greater flexibility!

Here’s what is possible with an f/1.4 lens:
Astrophotography: Capturing Clear Starry Skies with f/1.4 Lens

 

Key concept (4): Establishing focus

One of the most challenging scenes you’ll encounter with a prime lens is when you use the maximum aperture to shoot small subjects close-up. It will be harder to get the subject reasonably in focus because the depth of field will be shallower than normal, i.e., the in-focus area becomes very thin!

You can handle such shots better by familiarising yourself with different techniques for precise focusing.  Some suggestions:

- Use an AF area mode with a tiny AF frame such as Spot AF mode. 
- Directly control focus by using manual focus mode with MF peaking. 
- Use the ‘Magnify’ function to check that focus is on point before you leave the scene

EOS R50/ RF35mm f/1.4L VCM/ FL: 35mm (56mm equivalent)/ Aperture-priority AE (f/1.4, 1/80 sec, EV -0.3)/ ISO 400/ WB: Auto (Ambience-priority)/ Cropped in post-processing

Manual focus with MF peaking helped ensure the tiny white bougainvillea flower was perfectly in focus despite the extremely shallow depth of field.