Prime vs Zoom Lenses

Is a prime or zoom lens best, which should you buy and what are the pros and cons of both?

Probably the second most heated debate any photographer will ever find themselves participating in, just behind “which camera brand is best?”, revolves around whether a prime or zoom lens is the best choice to mount on the front of a camera. If you’ve wondered this yourself then please read on to find the definitive answer… well… maybe not… but you’ll learn what I choose to shoot with and why. So… which is better… a prime vs zoom lens?

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This article assumes you have a basic knowledge about the difference between a prime and a zoom lens.

The Answer Is…

The answer to the prime vs zoom lens debate is: well there is no single answer. The shortest reply I am able to give is: ‘both’. A slightly longer variation of that answer is ‘it depends’. Now, before you start throwing things in my general direction – let me explain:

I have a selection of both prime and zoom lenses in my kit. However, very rarely will I put them all in a backpack and trudge off to a photo shoot. I probably wouldn’t get out the door before I’d be too exhausted to continue – lenses get heavy very quickly :). I will usually take a small selection of lenses based on what I am going to be shooting, the look I am going for and what creative mood I am in at the time.

Let’s go through each of the factors I consider when deciding what lenses to pack and discuss how each lens attribute helps make the decision:

The Subject

The most important question when deciding whether to pack a prime vs zoom lens (or lenses) is based around what I will be shooting. If I will be in a situation where the subjects are moving around rapidly and changing size in the viewfinder (sports, moving vehicles, children, etc) and I won’t be in a position to move around easily, then a zoom lens will make a lot more sense than a fixed one. I don’t want to miss a critical shot because I was in the middle of changing lenses! On the other hand, if the subject is moving relatively slowly, or won’t change much size (landscapes, architecture, portraits, etc) and/or I can move around freely to change composition, then a prime lens may be a good candidate.

With the above in mind, if I’m going to be shooting something I’m not familiar with then I’ll usually choose a zoom lens.

Not being able to move around inside the hot air balloon basket called for the use of a zoom lens

Creative Style

Another important factor in the prime vs zoom lens debate that is often overlooked is how your shooting style changes when using the different lens types. Zoom lenses tend to make people think a lot less about the photo they are taking and how different angles and perspectives change the overall look and feel of a photo. With a zoom lens you can stand in a single spot and with a twist of the wrist you can change what is seen through the viewfinder. This can often encourage laziness and will discourage the photographer from exploring different angles and perspectives that could turn an OK photo into a stunning one. A prime lens forces you to move around and explore different angles and viewpoints, which can lead to much more interesting photos.

Image Quality

The most often touted reason that people will claim that prime lenses reign supreme is that they produce a much higher quality photo than a zoom lens. Prime lenses are optimised for a single focal length, whereas a zoom lens needs to make compromises to be ‘good’ throughout their range. This was indeed the case several decades ago, but with advances in computer aided optical design and superior glass coatings, the gap between the two has narrowed to the point that for all but the most demanding of applications most people will not see a difference.

It is still true that (in general) a prime lens will have better edge-to-edge performance than a zoom lens of similar quality – but most photography doesn’t suffer if the very corners of your image aren’t tack-sharp (unless of course you like to shoot brick walls). Centre to mid-frame sharpness will be very similar between a good zoom and a good prime lens.

If am am chasing as much resolution and sharpness as possible in my photos, and the subject allows for it, I will choose to shoot with a prime lens. Landscape photography is a good example of when I am looking for very high levels of image details – mountains, lakes and rivers don’t often move very quickly and I often use prime lenses for the ‘creative’ reasons outlined above.

Taken with a zoom lens with ‘soft’ corners – can you tell?

Vibration Reduction

Most prime lenses under 100mm focal length don’t come with any form of image stabilization, whereas many modern zooms have this feature included. Vibration reduction can certainly come in very handy in some situations and if I will need this feature then I’ll pack the zoom lenses with VR included.

Please do remember though that image stabilisation only helps reduce camera + lens shake – it does nothing to stop a moving subject (only a faster shutter speed will do that!). 90% of my landscape photography is done on tripods where image stabilisation isn’t useful. If your photography is done in strong light with fast shutter speeds and shorter lenses you may not find image stabilisation all that necessary.

If i’m shooting somewhere where light levels will be quite low and the subjects aren’t moving very fast, I’ll often go for a stabilized zoom lens. This will allow me to stop the lens down to get a decent depth of field and still have sharp images. The same goes in situations where a tripod isn’t practical or allowed (inside buildings, caves, churches, etc).

No image stabilisation required when using a tripod

Lens Speed

This section isn’t talking about how fast a lens auto-focuses, but how much light it can gather. In the photography world, the more light a lens can gather, the ‘faster’ it is. A lens with a larger maximum aperture (small ‘f-number’) lets in more light than one with a smaller aperture.

Most high-quality prime lenses under 100mm focal length have an aperture of f1.8 or larger. Zooms of similar optical quality on the other hand usually start at f2.8 or smaller. A lens at f1.8 will allow almost 4 times the amount of light into the camera than one at f2.8. It will in turn give a 400% higher shutter speed, with a blurrier background to boot.

A larger aperture (higher f number) will allow for smoother backgrounds and higher shutter speeds than a smaller one. If this matters much will depend on what you are trying to achieve:

  • Landscapes: Doesn’t usually matter as you would normally stop down to f8 or smaller for maximum depth of field. Tripods mean that high shutter speeds aren’t generally required.
  • Portraits: Usually matters as a smooth background and shallow depth of field is often desirable
  • Architecture: Usually doesn’t matter as you would normally stop the lens down to f5.6 or smaller
  • Birds & Wildlife: Usually matters as a smooth background is often desirable to isolate the subject and a high shutter speed is often needed
  • Street & Event: Usually matters as a larger aperture allows for more creative compositions
  • Sport: Usually matters as a smooth background is often desirable to isolate the subject and a high shutter speed is often needed

85mm at f1.8 allowed me to blur out the busy background

Price

Good glass costs big money! There is no getting around that fact – and both high-end prime and zoom lenses can cost a lot of money. It is often argued that prime lenses are cheaper than their zoom lens equivalent – and that can be the case when you can get away with one or two primes to cover the same range as a zoom – but many people will replace their zoom lens with 4-5 primes, which will cost similar, if not more money than the zoom.

For example:

A very popular trio of zoom lenses in the Nikon camp is the 14-24 f2.8 + 24-70 f2.8 + 70-200 f2.8. These three lenses currently cost somewhere around US$6000

A full Prime kit to cover a similar focal range would include 16 f2.8 + 20 f1.8 + 24 f1.8 + 28 f1.8 + 35 f1.8 + 50 f1.8 + 85 f1.8 + 105 f2.8 + 180 f2.8. Not only is that a LOT of lenses to carry around – together they cost around the same (slightly more in fact) than the three lenses above.

However – most people would choose a subset of the above primes. Personally I’d go for: 20 f1.8 + 28 f1.8 + 50 f1.8 + 85 f1.8 + 180 f2.8 which comes in at around half the cost of the three zoom lenses.

There are obviously many more choices for both zoom and prime lenses than presented above, at many different price levels – but the lenses presented above are all excellent and (importantly) have comparable image quality. Each camera manufacturer and third party lens makes have their own equivalent lenses – the prices are different for all of them, but the comparison between price points generally holds true.

Size & Weight

Prime lenses are very often much smaller and lighter than a zoom lens. This can be a consideration if you are trying to be discreet or if you are trying to travel light. However if you travel with several prime lenses they will take up more room in the bag than a zoom and probably weigh just as much.

As a comparison between a single zoom and three primes to cover a similar focal length:

Nikon 24-70 f2.8E VR: 150mm long x 90cm wide and 1kg in weight

vs

Nikon 24 f1.8G: 83mm long x 80mm wide and 350g in weight

Nikon 50 f1.8G: 52mm long x 70mm wide and 180g in weight

Nikon 85 f1.8G: 73mm long x 80mm wide and 350g in weight

Most of the time weight matters little to me in my decision making process. I’d rather suffer with the heavier option if it means better images.

Prime vs Zoom Lens: Summing Up

From the above it is pretty clear that there is no one ‘winner’ in the prime vs zoom lens argument. The reality is that both types of lens have a valid place in a photographer’s bag. The question becomes more about which lens is better for a particular situation:

  • Landscapes: Primes where I know I can take my time and move around. Zooms if I can’t change locations easily (waterfalls, cliff edges) or if I know the scene will change quickly. I will also take zoom lenses if I know the conditions are going to be poor where constant lens changing could get debris on the camera sensor (windy, dusty, very wet)
  • Wildlife: I will often use zoom lenses for wildlife photography (with the exception of birds) as the subjects are usually fairly fast moving and the scene/composition often changes very quickly.
  • Birds: It is very rare to need anything but the longest focal length I own when doing bird photography. If I could afford one of the big prime lenses (500/600/800mm) I would use those due to their insane image quality and light gathering ability. I currently make do with a Sigma Sport 150-600 zoom lens.
  • Events: Event photography is tricky and depends on the event, but if ever in doubt I will always go for the zoom lenses. Action is often fast with little time to change lenses – however if there is plenty of opportunity to move about then I may choose a prime lens or two. Ideally I’d take two camera bodies – one with a zoom that stays attached and another I can put a prime lens on.
  • Walk-about: It really depends on my creative mood when walking around looking for general photos. If I want a particular look then I’ll put on a prime lens. If I’m not sure what I want to shoot then I’ll usually put on a zoom lens.
  • Portraits: I generally prefer longer focal length prime lenses with wide apertures for portrait photography. The wide aperture generally allows for maximum subject isolation when required and portrait sessions generally allow for lens changes with no issues.
  • Travel: For travel I usually pack a zoom lens that covers a fairly wide focal range. Sometimes adding small, fast prime into the bag ‘just in case’ I need the wide aperture. When I travel I usually want to travel as light as possible without giving up the versatility of having a wide range of focal lengths available to use.