Prime versus Zoom: Can You Tell the Difference?

12Share

The first zoom lenses were not very good. Manufacturers of early zooms made optical concessions in the name of convenience and flexibility. The ability to change your lens’s field of view—eliminating the need to carry numerous prime lenses and swap them on the go—was, and still is, enticing to many photographers. Ever since the birth of the zoom, photographers have debated which option is better: fixed focal length prime lenses or variable focal length zoom lenses?

Note: This article was originally published 10 years ago. The text and images in this article have been updated.

Why did early zooms underperform and create an indelible reputation for not being as good as their fixed focal length prime siblings? Well, to get the light traveling through a zoom lens to behave properly when the focal length changed, optical engineers had to add more lens elements along with mechanical systems to move the glass physically. The greater number of elements and glass-air interfaces you have in a lens, the greater the chance for some undesired optical degradations, such as chromatic aberrations, distortions, softness, and more.

Today’s zoom lenses are better than ever, and many pros use zoom lenses exclusively—often never employing fixed focal length prime lenses. One can argue, however, that the same technology and manufacturing processes that have made the zoom lens better are likely making new prime lenses better, as well.

It was hard (impossible?) to “pixel peep” in the days of film, but now pixel peeping is a mainstream digital sport. If we compare a photo taken with a zoom lens to one taken with a prime, do we need to pixel peep to see the difference? Or is this a moot comparison in the modern photographic era? Is a zoom lens just as good as a prime?

Let’s take a look!

Example 1: Here we compare the FUJIFILM XF 35mm f/1.4 R against the “kit lens” FUJIFILM XF 18-55mm f/2.8-4 R LM OIS. For those unfamiliar with the Fujinon lenses, the XF 35mm is known not for its sharpness, but for having great “character,” and the 18-55mm is referred to, by some, as the “non-kit lens” as it outperforms entry-level kit lenses from other manufacturers. The images below were shot in raw format and processed identically—no unique adjustments to sharpness or color. Can you spot any difference between the two lenses?

FUJIFILM X-T3 with the XF 35mm f/1.4 (left) and XF 18-55mm f/2.8-4 (right) lenses, set at f/8, ISO 160. Identical processing of raw images.

100% crop

200% crop

Example 2: Here is another pair of images from the same two lenses.

Again, the FUJIFILM XF 35mm f/1.4 (left) and XF 18-55mm f/2.8-4 (right) lenses.

100% crop

100% crop

200% crop

Example 3: Here is one more pair of images from the same two lenses with a crop to show corner detail.

One more time: the FUJIFILM XF 35mm f/1.4 (left) and XF 18-55mm f/2.8-4 (right) lenses.

100% crop

Example 4: Just to mix it up a bit, here is the Nikon AF DC-NIKKOR 105mm f/2D lens going up against the Nikon AF Zoom-NIKKOR 80-200mm f/2.8D ED lens (no longer manufactured).

Nikon D300 with the Nikon DC-NIKKOR 105mm f/2 and the Zoom-NIKKOR 80-200 f/2.8D ED lens, both at f/8, ISO 200. Identical processing of raw images.

100% crop

Can you tell the difference? I cannot.

Even with the 100% crops, the images look identical. At 200% you might see a tiny bit of difference, but we are literally splitting pixels at that point—an absurd level of “pixel peeping.” There is nothing in these examples that would be discernable on a print, on the screen, or even on a billboard.

Granted, I am presenting images that were created in the heart of both the prime and zoom lens’s sweet spots (midrange aperture setting), but the results at other apertures were very similar.

So, if you cannot tell the difference between a prime and a zoom lens, why would you ever want to carry a prime lens (or multiple prime lenses) in your bag? I will give you a few reasons.

  1. Wider aperture. While there are exceptions, many prime lenses will have a larger maximum aperture when compared to even the most expensive zoom lenses. This wider aperture will allow you to create images with shallower depth of field, as well as photograph in conditions with less light.
  2. Smaller and lighter. A prime lens is likely smaller and lighter than a zoom lens of a similar focal length, albeit with only a single focal length. If you are trying to travel light and know the focal lengths you need, a bag full of primes is lighter than a bag full of zooms.
  3. Unique lens designs. There aren’t too many zooms around that can replicate the specialized effects of tilt-shift, macro, fisheye, soft focus, or other specialized lens types, which are integral to certain niche shooting applications.

My allegiance to the prime lens (see this article about the venerable 50mm lens) is public, but I still own and use zoom lenses from time to time!

What are your thoughts in the age-old debate of prime lenses versus zoom lenses? Let us know in the Comments section, below!

12 Comments

I often hear this argument that primes are better quality.... perhaps at extreme pixel peaking. But I can't see the difference.

HOWEVER a newer lens almost always is better quality than an older lens,   Lens design has improved great over the last 20 years or so.  A new/current premium 70-200mm is highly likely to be better than a 10 year old 85mm, and I think the new 85mm will be better (and probably even faster) than a 10 year old 70-200mm.

To me age of the lens is the more important metric.  Your thoughts?

Hey Patrick,

I cannot disagree with you there. Modern lenses are much sharper than older ones—plus they have superior coatings and other tech that further widens the divide.

Lenses made for film cameras only had to resolve for film, but now that digital cameras have way more pixels than film had grains, manufacturers have had to up their optical game to keep up with the pixel-peeping public!

Having said that, if you aren't making large prints or putting your nose up to smaller prints, a vintage lens on a mirrorless or DSLR camera can give you a unique look while being very fun to use! It's not always about sharpness and pixel peeping. :)

And, you are correct. Most people cannot see the difference between a prime and a zoom—but zoom lenses pack convenience while primes generally are smaller and lighter, so both have their advantages.

Thanks for reading!

Best,

Todd

Great article - thanks!  It makes me feel a bit better about using my zoom lenses so much (I've only been at this just over a year so am still very much a beginner trying to learn as much as possible).  I love using zoom lenses when I'm out and about, at a park, the zoo, etc. as it gives me so much flexibility on what to shoot without having to swap out focal lengths to get closer to something (that I might not be able to get closer to).  My zooms are both Nikon kit lenses though so I know they're probably not the best quality, but honestly, I still think they take really great pictures.  I do use primes when I'm shooting portraits of people, and I've tried using them when out and about too (at the recommendation of many YouTube photographers) to force myself to get better at it.



One thing I noticed in your comparison images is that your prime lens seems to have a bit more of a "purple" look to it - I'm not quite sure how else to say it.  The highlights seem to be more blown out (pardon me if that isn't the best way to say it) on the zoom lens - more details visible in the sky for instance.  And the shadows seem to be deeper too on the prime.  I was wondering why that is - I would think that more elements in the lens would stop more light so that the zoom lens would have "darker" images but it seems to be the other way around.  I know you can change that in editing too, so it's really probably a moot point - I was more curious than anything as it seems counterintuitive to me.  And maybe I'm imagining it!

Anyway - thanks again for a great comparison! 

Hi Sean,

Thanks for the kind words!

There is definitely something to be said for the convenience of zoom lenses and there is also something to be said for the portability and optical capabilities of a prime!

Regarding the difference between the lenses there are some (kind of) scientific answers.

For the purposes of this article, I processed the images identically—not to look identical. I could have tweaked the color in one or both images to make them closer, but I wanted to illustrate the differences in how the lenses were rendering the scene.

Every lens transmits light differently and, because of that, colors get affected as well. I can't say that a prime allows the transmission of more blue (or purple) light, but it definitely looks that way above. I am sure a different comparison with different lenses would tell a different story. You could probably even put two "identical" lenses together and get some discrepancies between the two images in color, shadows, and sharpness with identical exposures. Although manufacturing tolerances are pretty tight these days, there are variations between optics in identical lenses as they come off the assembly line.

And, you are correct...in general, the more elements of glass light has to pass through, the less bright it will be. With modern optical glass, this light loss is fairly negligible, so you wouldn't see a big difference in lenses with different numbers of elements. Case in point is the Olympus 25mm f/1.2 prime lens that has 19 elements (I think that is a record for a prime lens). That is more glass than many zoom lenses!

Anyway, thanks for reading, Sean! Let us know if you have more questions and good luck as you continue your photographic journey!

Best,

Todd

 

Excellent article and thought-out comparisons.  I am a lifelong (75) amateur and your article showed the very minor differences, in my mind negligible, between prime and zoom for non-professionals.  I like the smaller size of most primes but the Fuji zoom is fairly small anyway. The photo differences are irrelevant (tiny) today for amateurs.  Save your money and don't be sucked in to prime envy!

Hi Richard,

Thanks for the comments and for sharing your experience! While the image quality differences can be small, there are definitely times that I like the size/weight advantages of a prime over a zoom!

Thanks for reading!

Best,

Todd

I believe it's like any strategic build of an tool arsenal....be it a kitchen, a camping outfit, or a camera bag. All things find their place and that certainly bodes true for lenses. That being said, you cannot beat the absolute rule of the prime for professional shooting applications, IMO. Focus pulling with a max aperture of 1.2! How can you beat that? So my quiver has 5 cinema primes and 2 pro zoom lenses, the former for the majority of work we do and the latter for run & gun, casual, and "in a pinch" jobs that call for flexibility on the fly. But it's nice to have the ability to do just about everything, and yes having one or two grab glass options when you really only need (or can fit) one lens. 

 

Hi Stephen,

I totally agree. I mostly shoot primes today, but always feel like I am missing the convenience of a zoom from time-to-time—especially for more "casual" shooting where ultimate image quality isn't the goal.

Wouldn't it be amazing if there was one lens out there that did everything you needed? :)

Thanks for reading!

Best,

Todd

As I'm currently switching from Nikon DSLR to Sony Mirrorless (hybrid shooting) I've been debating lens selection - primes or zooms. With the Nikon's I almost always used Zooms which were bulky and not particularly fast (all of them topping out at f2.8 except the zooms at f4/5.6); but when I looked at a bunch of photos I had taken I found I was generally racked fully to one end of the focal range or the other... rarely in-between. So I'm now planning my Sony lens selection with mainly primes in mind, get the faster optics and still maintain a decent weight in my bag (although that 200-600mm zoom looks magical for the money compared to the prime offerings).

Hi Graeme,

I think I know how you feel. When I switched from Nikon to FUJIFILM I also basically abandoned zooms. I do have the very nice 18-55mm f/2.8-4, but I rarely use it outside of casual event photography or family gatherings.

Today's zooms are very good, as you know, but there is something to be said for traveling lighter and having a smaller camera around your neck or over your shoulder!

Thanks for reading Explora!

Best,

Todd

If you're going to compare lenses, don't do it at f/8.  Even a bargain-bin M42 zoom lens can look very good at that aperture.  Try these again at f/2.8 (or at least close to it) and differences in lens quality will become much more apparent.

Hi Ian,

You make a valid point there. This article was an update to an existing piece with, honestly, a horrid pair of photos. I did not know if the hundreds of comments left on the original article would remain, so I tried to keep the camera settings similar to avoid confusion.

This was not meant to be a scientific comparison as there are variations in lens performance of identical lenses due to manufacturing variations, so an apples-to-oranges test just shows the results for the lenses I have in hand.

To add a bit of variety, the second set of images were shot at f/4 (the maximum aperture of the zoom at that focal length) for a more "real world" comparison on the fringes of the lens's sweet spot.

Thanks for reading and thanks for the comment!

Best,

Todd