Camera lenses can be divided into two broad groups: prime lenses and zoom lenses. Prime lenses, which offer a single focal length and can’t zoom in or out, may seem to be inherently less useful than zoom lenses, but that’s not necessarily the case. Prime lenses can offer a wide range of benefits, and in this guide, we’ll break down what you should know about prime lenses and why you should consider adding prime lenses to your bag.
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What Are Prime Lenses?
Prime lenses are best understood by looking at the difference between a prime lens and a zoom (explained in detail here: prime vs zoom lenses).
The major difference is that a prime lens offers a single focal length. Focal length, typically given in millimeters or “mm,” describes how much of the scene you will capture with that lens, from wide to telephoto. A smaller number is a wider angle. For example, on a full-frame camera, a 20mm lens will be a wide angle, a 50mm will be a “normal” or moderate field of view, while a 105mm will be a narrow or telephoto field of view.
Field of view changes depending on the camera format that you use – AKA the size of your digital camera sensor or film. Since the closest thing to a “standard” format is full-frame digital (or 35mm film), this gives rise to the concept of full-frame equivalent focal lengths. You can read more in our article on crop factor. For ease of reference, this article will always refer to full-frame equivalent focal lengths.
Unlike a prime lens, a zoom lens by definition offers a continuous range of focal lengths, such as 24-70mm lens. This means that the lens will cover 24mm, 25mm, 26mm, and so on, through 70mm (and all the spaces in between).
While it may seem like this allows a zoom to replace a huge range of prime lenses, it’s not as though you need to carry a prime lens at every single focal length. Lens companies don’t even sell primes at every focal length. Instead, primes are available at typical benchmark focal lengths, like 20mm, 24mm, 35mm, and 50mm. A well-equipped photographer might only need a 24mm and 50mm lens to have a “complete” kit for their photoshoot.
Prime lenses and zoom lenses have a large number of differences in features, benefits, and drawbacks. But almost all of those differences stem from the single major difference that prime lenses offer one focal length and zoom lenses offer a range. Since this article is dedicated to prime lenses, let’s look at some of the benefits they offer.
Benefits of a Prime Lens
1. Simpler and Smaller Construction
Prime lenses have a wide range of benefits, and understanding what they offer to you as a photographer can make a big difference in the images you create. The most immediately visible reason to use a prime lens is in the size and weight. While not always true, many prime lenses are small, lightweight, and portable, making them a good choice for situations where you need to be mobile.
That said, one important consideration when looking at the size and weight advantage of primes is to understand the “class” of lens you’re looking at. A high-end prime with a very fast aperture might be bigger than a lot of zooms. But if all else is equal and features are similar, prime lenses almost always have a size and weight advantage.
But why is that the case? As a prime lens only has to cover one field of view, the optical formula (all the differently shaped pieces of glass that make up the insides of a lens) can be a lot simpler. All the parts inside are simpler, too. A zoom lens needs to move different elements around to change the focal length, and many zooms have to extend the lens barrel itself to make this possible. All this adds up to more glass, more material, and more complexity in the design. Below, you can see the optical diagrams of a basic 50mm prime lens on the left and a zoom lens that covers 24-85mm on the right. As you can see, if you’re just trying to shoot at 50mm, you can save a lot of size and weight by going with the prime.
2. Faster Apertures
Size and weight aren’t the only advantages of a prime lens. In many cases, they’re also capable of shooting at much wider aperture settings.
For example, many zoom lenses struggle with f-stop. A typical zoom will max out at aperture values like f/4 or f/5.6. Only fast, professional-grade zooms are usually capable of apertures as wide as f/2.8. By comparison, most prime lenses have a maximum aperture of at least at f/1.8, and high-end primes can go even further, down to crazy values like f/0.95 on some specialty lenses.
As a photographer, this means you can get shallower depth of field with prime lenses to better isolate your subject against a blurry background. It also lets you shoot in low-light conditions more easily, allowing for a lower ISO or a faster shutter speed in dark environments.
Along with faster apertures, prime lenses are also typically very sharp. With the optical formula only needing to be optimized for a single focal length, prime lenses can have great sharpness and low levels of optical defects, like chromatic aberrations, particularly when compared to zoom lenses that cost a similar amount of money.
4. Lower Prices
Especially taking the three points above into account, prime lenses can be great values and offer capabilities to beginners that would be prohibitively expensive on a zoom. One of the most recommended beginner lenses is the so-called “nifty fifty.” It’s a catchy name for a 50mm f/1.8 that can often be purchased for just a couple hundred dollars, or less when bought used. All this while offering better image quality, a wider maximum aperture, and smaller size than almost any zoom.
The benefit of a lower cost doesn’t just apply to basic or used primes, however. Prime lenses of all focal lengths and capabilities are cheaper than zooms in the same tier of performance. While this lower cost may be counterbalanced if you need to buy more lenses overall (a point we’ll look at further in the Drawbacks section below), usually photographers can still put together a high-quality set of prime lenses cheaper than a high-quality set of zooms.
5. Special Features
We’ve already seen how prime lenses can offer aperture capabilities that just aren’t possible in zoom lenses. Primes are capable of even more, however, with prime lenses of special designations. For example, almost all macro photography lenses are prime lenses, making primes the way to go if you need close-focus capabilities. Most brands make macro lenses that can focus at 1:1 magnification, while some brands offer macro lenses that can focus all the way to 5:1 like the Laowa 25mm f/2.8 Ultra Macro, which is approaching the territory of basic microscopes.
Other specialty prime features include tilt-shift and defocus control. Both of these are more advanced technical capabilities used in genres like architectural and portrait photography respectively.
As prime lenses are also less expensive to design and construct, third-party manufacturers are able to produce unique designs and capabilities on their primes. These range from the odd-looking probe macro lens from Laowa, ultra wide or ultra fast lenses like a 9mm or f/0.95 aperture lens, and more.
One last benefit of prime lenses is a little harder to quantify, as it’s more artistic. After shooting with a prime lens for a while, you can start to visualize the focal length, making it easier to spot potential compositions and understand framing, all before you lift your camera. Some photographers only ever shoot with a single prime lens, like a 35mm or 50mm, for exactly this reason.
Drawbacks of a Prime Lens
After all those benefits, it might seem like there’s no reason for zoom lenses! That isn’t the case, however. While prime lenses do possess a number of advantages, and can be a great choice for many subjects, they do have limitations.
1. Field of View
With a prime lens being limited to a single focal length, you can’t easily change your field of view while remaining in the same spot. While you can always “zoom with your feet”, by getting nearer or further from your subject, this changes the appearance of your photo by altering your perspective. It’s also not as simple as just twisting a zoom ring. As described in our article on making prime lenses more versatile, you can shoot a panorama or crop in to get a wider or narrower composition, but this can take time or cost you resolution.
2. Switching Lenses
If you want to get access to different fields of view, you may need to switch prime lenses more frequently than zooms. You could end up spending more time changing gear and less time shooting, as well as more time exposing your sensor to dust and debris.
This can be particularly problematic in fast moving or hazardous situations, but it is slightly counterbalanced by the greater resilience of prime lenses to environmental hazards like dust, thanks to the fewer moving parts and more simple mechanical design.
3. More Lenses Necessary
Even though prime lenses are usually simpler, lighter, and less expensive than zoom lenses, things start to change when you look at them as a kit. A 24-200mm or 18-200mm zoom lens can effectively cover an entire day’s worth of photographic opportunities, while even mid-range zooms like a 24-105mm can be all you need for most situations. In contrast, you’d potentially need a 24mm, 50mm, and 105mm to cover the same situations, and maybe even more (like a 35mm and 70mm) if you’re concerned about too big of a focal length gap.
As a result of this inflexibility, manufacturers have recently leaned into primes being specialty lenses – releasing primes that do things a zoom could not reasonably do. This often makes new primes, particularly for mounts like Nikon Z and Canon RF, more expensive propositions than prime lenses of the past.
You can still build out a full kit made of prime lenses, particularly if you’re using an older mount or are willing to adapt lenses, but it’s more challenging than it was before.
Are Prime Lenses Still Relevant Today?
I think gear manufacturers have the right idea: Prime lenses these days are at their best in special roles. Whether this means making really fast aperture lenses, offering unique capabilities like macro or defocus control, or capitalizing on the size benefits by being super small and lightweight, prime lenses do still have a niche.
Some of the other historic benefits of prime lenses aren’t as relevant these days. For example, with lens designs and manufacturing continuing to advance, zoom lenses can now offer similar levels of optical quality, while still conferring all the flexibility of a zoom (just consider our recent review of the Nikon Z 70-200 f/2.8). In fact, at the highest end, lenses like the Canon 28-70mm f/2 have even come close to a prime’s fast aperture, albeit at a significant cost and weight penalty.
In my own kit, I’ve found that primes can be a great supplement to my favorite zooms. I particularly like having a fast wide angle lens for shooting astrophotography, like my 24mm f/1.4, as well as a macro lens like my 105mm. Portrait photographers will also find fast 50mm and 85mm lenses to be a go-to option for portraits with blurry backgrounds. Wildlife and sports photographers have a place for prime lenses in their kits, with 300mm or longer telephoto lenses with fast apertures offering high performance.
As a result, prime lenses are still relevant today, and for a wide range of the market, even if they are no longer the only or most popular optiosn.
How Many Prime Lenses Do You Need?
Only you can answer how many prime lenses you need. Depending on your interests, style of photography, and budget, you might want to build out a kit featuring 7 primes across your favorite focal lengths, or you might just stick with a few zooms and no primes at all. There’s no right or wrong answer. Instead, I’d recommend taking a look at what you shoot and what a prime lens can do for you as a photographer, then building out your kit as needed. Ross Martin talked about this a lot in his article on buying the right lenses for photography.
If you’re looking for a recommendation for your first prime, I’d suggest a 28mm, 50mm, or 85mm. For landscapes, a fast 28mm can make astrophotography far more practical. For mixed use, a 50mm can be an inexpensive way to get started with prime lenses, and it represents a classic field of view. Lastly, an 85mm will offer one of the most affordable ways to get that shallow depth of field look in portraits.
Prime lenses might seem like a basic or even outdated category of lenses compared to the latest zooms. But thanks to some fundamental physics, they can be faster, smaller, and sharper than zooms, and can open up new frontiers in your photography. Whether you’re looking to add a specific capability to your kit, or are just looking for some inspiration for your compositions, I’d consider primes. They can give you a whole new view on your subject, literally.
I hope you’ve enjoyed this guide to what you should know about prime lenses. If you have any questions, let us know in the comments below.