In this post, we’re going to talk about Prime lenses versus zooms. When should you use each and which are better?
Let’s start with the basics: what are the differences between prime and zoom lenses?
What is a Prime?
A prime lens is a lens with a fixed focal length, which means the angle of view can’t be changed. Effectively no zoom. The only way to make your subject closer with a prime lens is to physically move the camera closer to the subject. The only way to fit more into the frame is to move it further away.
Prime lenses’ fixed focal length is represented by the mm number which is on all lenses. So for example I film my YouTube videos with a 16mm lens, a basic rule of thumb is the lower the mm number the wider your shot will be, so 16mm is pretty wide angle. The larger numbers you’re likely to see on prime lenses are 50 or even 85mm, which will be more narrow with your subject appearing closer.
What is a Zoom?
Zooms however do exactly what the name would suggest, they can zoom in on a subject. This is called a variable focal length. They will have a zoom ring (or controls in the camera) to make your subject appear closer without having to move the camera.
Again the focal length is represented by mm number, but instead, it will be 2 representing a range. For example, the focal length range of this lens is 18-105mm which means that the widest the lens with be 18mm and at the most zoomed-in 105mm and everything in between.
Prime Pros and Cons
So at this point, you may be thinking, why bother with a prime lens if a zoom gives you more options of focal length? Well, there are lots of good reasons.
A huge reason you may want to opt for a prime lens is the aperture. Generally, you’ll find a fixed focal length lens will have a wider maximum aperture than their zoom counterparts. Aperture is represented by the f-number on your lens with the lower the wider. For example, this 16mm lens has a maximum widest aperture of f1.4. You’ll often hear this described as a fast lens.
And a wide aperture provides plenty of plus points to a lens, firstly allowing a lot of light onto the camera’s sensor. This is will allow you to shoot in low light environments without introducing blur or having to crank up the ISO (effectively artificial light to brighten up images)
This can be a vital feature of a lot of users and Zoom lenses in comparison will be much darker, making low light and indoor shots look a lot more blurry or noisy.
A wide aperture also allows for a shallower depth of field effect, often known as bokeh. A shallow depth of field lets you have blurry or creamy backgrounds beyond your subject, which is great for separating your subject from your background. Perfect for professional-looking portraits for example. As a prime lens only has to cater for a single focal length they can generally offer wider apertures compared to zooms.
Other factors to consider are size and weight, primes are on the whole smaller and lighter than zooms. Portability is a big factor especially if you’re using a small APS-C mirrorless camera that is ultra-portable, opting for a zoom lens will mean massively increasing the he space you’ll need to take your kit out with you.
Price can also be a huge plus point to a prime, of course, there are very expensive options in both categories. However, generally you can find fast prime lenses very cheap, especially if you’re ready to forgo autofocus. A big factor if you’re on a tight budget.
So primes offer a lot of plus points, but if you need a lot of reach (for sports and wildlife photography) then primes will rarely be the right option so definitely offer less versatility than a zoom.
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Zoom Pros and Cons
And on the topic of versatility, that’s something which zoom lenses definitely do provide. The ability to go from a wide-angle shot to a more zoomed-in one without having to move is the main reason you may opt for a zoom lens.
The difference in a shot taken at 18mm compared to 105mm can be hugely advantageous for all types of photography, especially sports and wildlife. Where the more zoom the better.
Now zooming in generally leads to more camera shake so you will find most modern zoom lenses will have image stabilization built-in, deducing shake and blurry which can be particularly useful for video work.
And despite me citing portability as an advantage of a prime lens, it can also be a pro of a zoom. Yes, it’ll be heavier and larger than a prime. But if you know you’ll need multiple focal lengths or different types of shooting. Using primes may need you to take multiple lenses out with you, whereas a single zoom may fulfill your needs.
As mentioned a zooms low light performance generally will be worse than a fast (wide aperture) prime. For example, the 18-105mm has a constant aperture of f4, which will be much darker than the 16mm f1.4. And many zooms will get darker the more you zoom in, reducing low light performance further.
Buy the Sony 18-105mm f4 on Amazon*
Which are Better?
The only answer to which is better is, well it depends! It depends on how you use your camera and what you want to achieve. For portraits or situations where you need good low light performance or shallow depth of field backgrounds, then a prime will be better.
If you prefer the versatility of shooting, and especially if you need reach from your shots (sports wildlife, etc) then zooms are probably the right choice.
For a long time, I was so convinced only of using zooms for the range, but I’ve found the Sigma 16mm f1.4 ideal for making videos such as this, whereas I’ll take zooms out for shooting out and about.
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