Prime vs Zoom lenses

Enthusiasts and professional photographers are often divided between those who rely primarily on zooms and those who rely primarily on prime lenses.  Prime vs zoom lenses is an ongoing debate.  There are plenty of top quality photographers in each camp.  The goal of this post is to help growing enthusiast photographers to understand the prime vs zoom lens issues, so as to help them decide which direction to take their gear collection specifically for the “normal” range of 24 to 70mm.

All lenses are compromises. Even when people describe a lens as “no compromise,” they are usually just talking about the image quality. Take for example, the “no compromise” lenses in the Zeiss Otus line up. These are prime lenses that are manual focus, massively heavy, and massively expensive. The Zeiss Otus 55mm F/1.4 may be one of the top lenses ever tested by DXOmark, but it costs $4,000, weights nearly a full kilogram and lacks auto focus. In terms of compromises, zoom versus prime lenses are among the most basic compromises to consider: convenience. Looking at all the basic compromises made in lens design:

  • Image quality (including sharpness, distortion, vignetting, etc)
  • Price
  • Weight and build quality
  • Aperture
  • Convenience and features (including focal length range, autofocus, image stabilization).

Speaking entirely generically about zoom vs prime lenses, prime lenses tend to offer faster aperture (wider apertures) and better image quality, where zoom lenses offer more convenience.

This discussion is applicable to all brands but I will focus the comparison on Sony, as it is what I shoot.   There are several ways we could do this comparison:

Kit/Consumer zoom lenses vs Kit/consumer prime lenses

Every APS-C entry level camera comes packaged with an 18-55 zoom lens, or some equivalent.   Most prime lenses, by their very nature, are geared more towards higher level users.  There really are only a handful of true “consumer” primes (those priced under $300).   Thus, this is not a very interesting comparison in my book.   Needless to say, the entry level zooms compromise in order to favor low price, low weight, and convenience.  As I said, there are very few entry-level/kit/consumer zooms.  An entry level shooter looking to avoid spending much, will find themselves compelled to stick to the zoom lens.

Professional Zoom Lenses vs. Professional Prime Lenses

While in this comparison the photographer would have many choices, I still find it an uninteresting comparison.  Professional zoom lenses consist of 2.8 aperture zoom lenses.  They are big, heavy and expensive (A minimum of $1,000, often $2,000).  The professional prime lenses, often with 1.4 aperture, are also big, heavy and expensive.    Image quality is excellent in both cases, but better among the primes.   The primes naturally have larger apertures.  The zooms still bring very good image quality and large aperture but compromising a bit in order to offer the convenience of a zoom.  It’s a simple comparison and comes down to the objective and subjective needs of the photographer.  In both cases, your choices will be very heavy and very expensive.

Professional Zoom Lenses vs. Prosumer/Enthusiast Prime Lenses

This is the comparison I want to examine in detail. By “prosumer/enthusiast” prime lenses, I’m referring to those that tend to still be priced under $1,000 and they tend to offer more moderate/fast apertures like F1.8 instead of F1.4.  They still offer larger aperture than professional zoom lenses (F2.8).  In most cases, the prosumer/enthusiast primes can still offer image quality superior to the professional zooms.

The “normal” range covered by the standard zoom lens is 24 to 70mm.   In covering this range, the enthusiast photographer has an interesting choice between professional zoom lenses and enthusiast/prosumer primes.    Beyond the obvious convenience image quality and aperture considerations, let’s also consider how this choice affects price and weight, which are important considerations to an enthusiast such as myself.

The Lenses being Considered:

The qualifying zoom lens:

Sony 24-70 F/2.8 GM:  $2200, 886 grams.

(Note to Canon and Nikon shooters:  There are more options for 24-70 F/2.8 lenses including third parties.  Thus, Canon and Nikon shooters can find lenses closer to $1,300 but of similar weight)

Prime lenses within the range   (in areas where Sony still has gaps, I included 3rd party):

Zeiss Batis 25mm F/2 (while slightly more expensive than most enthusiast primes, Sony does not currently have a lens of the focal length):  ($1170, 335 grams)

Sigma 24mm F/1.4  ($900, 665 grams)

[Please note, Sony does not have a native 24mm lens.  Therefore, I included two third-party options.  The Zeiss Batis has the size and aperture of an enthusiast lens, but is priced more like a professional lens.  The Sigma is priced as an enthusiast lens, while having the aperture and weight of a professional lens]

Sony 28mm F/2 ($425, 200 grams)

Sony 35mm F/2.8 ($700, 120 grams)  — cheaper Rokinon 35mm F/2.8 ($350)

Sony 55mm F/1.8 ($900, 281 grams)

Sony 85mm F/1.8 ($550, 371 grams)

[Note to Nikon and Canon shooters:  Your list of options will differ, but will find options at 24mm, 35mm, 50mm, and 85mm at similar prices]

How to Combine Prime Lenses to Match the Zoom

The 24-70mm zoom lens obvious covers every focal length from 24mm to 70mm.  You can use this lens for everything from fairly wide landscapes to short telephoto portraits.

There is no need to buy 46 different prime lenses to cover every focal length.   While I listed 5 different focal lengths above, there would be no need to purchase all 5 to cover the range offered by the zoom lenses.

In truth, a photographer can cover the entire 24mm to 70mm range effectively with just 2 or 3 prime lenses, picking based on how they shoot.

Winter Evening in the Park
Taken with Zeiss Batis 25mm F/2

Looking at the above list, the 85mm already extends beyond the range offered by a 24-70mm, and therefore may not be necessary.   Today’s cameras offer enough resolution to do significant cropping and still have enough megapixels for large prints.  For example, if you were using a 24mm prime lens on the Sony A7riii, you could put the camera into “APS-C mode” and get a 1.5 crop, effectively giving you a 36mm image, still with 18mp.  (Not that long ago, 18mp and smaller was still standard on most cameras).

Thus, one could make do with just 2 primes and basically cover the same range offered by a 24-70 zoom.   You could use a 24mm lens as both 24mm and 36mm.  Then you could add the Sony 55mm F/1.8 and it could cover 55mm and 82mm.   Effectively covering 4 different focal lengths, and only missing a small gap between 36mm and 55mm.

For most people, if you are skipping the zoom lens, I would suggest using 3 prime lenses.   But as shown, you can get away with just 2 primes.  In terms of purely covering the focal length range, I don’t ever see a need for more than 3 prime lenses.  Which 3 lenses will depend on your shooting style.  If you are rarely shooting wide, you might want the 28mm, 55mm and 85mm.   If you are primarily shooting on the wider side, you might want a 24mm, 35mm and 55mm.

55mm at F8

The Advantages and Disadvantages of Zoom Convenience

If you are using a 24-70mm F/2.8 zoom lens and you want to change focal length, you just turn the zoom ring.

If you are shooting with a prime lens, it’s not so easy to change your focal range and field of view.   You have three options to mix and match:

  • Foot zoom, either step forward or step back
  • Cropping
  • Changing the lens

All three of those options carry some significant disadvantages.   In terms of foot zoom, there isn’t always enough room to step forward or back.   Quite often, you simply cannot step any further back.  If you’re shooting a headshot portrait, a wide lens would require you to get uncomfortably close to your subject, into their personal space.

In the below images, by using a 12-24 zoom, I was able to quickly capture the different perspectives at both 12mm and 24mm.

Cropping a high megapixel image is often feasible but can be less than ideal.  First off, you cannot make an image wider by cropping so it only works in one direction.  You can effectively increase your focal length but not decrease it.  Secondly, by cropping you are inherently throwing away some of your image quality.   Depending on the quality of the lens, the camera body and the technique, the more you crop the more any IQ flaws are exposed.   If you are cropping from a 24mp camera, a 1.5 crop will result in a 10mp image.  While 10mp is still perfectly adequate for printing a 11X14, there is little margin for error and you can’t print  much larger without losing noticeable detail.

Changing the lens brings the obvious draw back of time consumption.   Even if you are very quick and proficient at lens switching, it still takes a minute or two.  Thus, it is not practical to take a quick landscape at 24 mm, quickly adjust for a 70mm shot and then go right back to 24mm.

It is therefore impossible to dispute the convenience of a zoom lens.  While there are workarounds for many people in many situations, none are ideal.   There is one advantage to using primes in my opinion:  When you don’t have the option to easily zoom, it forces the photographer to be more considerate of pre-planning the composition which leads to better photographs.  But if you are a highly skilled professional photographer who needs to deliver final products to your client, you probably don’t want or need to be forced into spending extra time considering composition.

The Price Differences

In our example, the Sony 24-70 F/2.8 GM lens costs $2200.  This is significantly more expensive than any of the prime lenses.   I dare say that many enthusiasts are not comfortable spending $2200 on a single lens.

Yet, the pricing structure works out quite differently when you try to compare it to full substitution of enthusiast primes.   Assuming instead of the zoom, the photographer purchased 3 prime lenses from those on the list above.  One of the cheapest combinations would still run $1,875.  The most expensive combination of 3 lenses would run $2,770.   Let’s run one realistic combination of 3 primes:

So in this comparison, the total is $150 more than simply buying the Sony 24-70 F/2.8 GM.

Thus, if purchasing the expensive Sony 24-70 F/2.8 GM allows you to forego the primes, it may actually be cheaper than assembling a kit of primes.

Yet you may have more flexibility to go cheaper with primes.  Not on our original list of choices is the Sony 50mm F/1.8 which is more of a kit-level prime but is priced at $200.  If for example, you were more concerned about the long 85mm end and the short 24mm end, you might decide to save money and compromise a bit more with the purchase of the Sony 50mm F/1.8.  That would save you $700 compared to the Sony 55mm F/1.8.   Now, instead of the combination costing $150 more than the zoom, the combination would cost $550 less than purchasing the zoom lens.

The Various Impacts on Image Quality

In most of the lenses I listed, the prime lens gives a 1-2 stop aperture advantage over the 24-70 F/2.8 zoom lens.  The only exception I listed was the 35mm/F2.8, which has the same aperture as the zoom option.  The faster apertures automatically come with certain advantages:

  • Better light gathering ability and low light capability
  • Ability to use lower ISO, thereby improving image quality
  • Narrower depth of field, thereby smoother and better bokeh

In addition, because of their simpler construction, the prime lenses will tend to mostly offer less distortion.   At comparable apertures, the primes are almost always sharper (since they get to stop down in order to shoot at 2.8).   Because of their wide apertures, the primes may have significant vignetting when wide open, but this is typically a non-issue once you stop down to 2.8, which is the starting point for the zoom.

Sony 85mm F/1.8
Taken with the Sony 85mm F/1.8, a zoom couldn’t get the same degree of bokeh

In other words, if you compare the prime lens stopped down to F2.8 or F4 to the zoom lens at F2.8 or F4, the prime lens will typically offer superior image quality across the board.   And if you do want to shoot wider than F2.8, you simply cannot with the zoom lens.

The only negative in terms of image quality with primes is the one identified about cropping.  With a zoom lens, you can get a full resolution image at every focal length.  If you crop the prime lens, you will be throwing away some resolution.

Combining Price and Image Quality

What about bang for your buck?  If you are spending $550 less than the 24-70 F/2.8 zoom lens, does it mean you are getting lesser image quality?  In all cases, the prime lenses are still giving you faster aperture than the 24-70 F/2.8.   According to testing at DXOMark, the image quality of the cheap $200 50mm F/1.8 is still superior to the $2200 24-70 F/2.8 GM.   Below please see their representation of sharpness comparisons:

Comparing the 50mm, the 24-70 F/2.8 and the 55mm

You do get what you pay for.  The $2200 24-70 f/2.8 is sharper at 50mm than the cheap $200 prime lens but it is awfully close considering the price difference.   Meanwhile, the $900 55mm F/1.8 is MUCH sharper than the $2200 24-70 F/2.8.

Weight Differences

The 24-70 F/2.8 GM is a heavy lens at 886 grams.  Combining 3 primes from the above list, the total weight will fall between 600 grams and 1,317 grams.   So the total weight may be a fair amount less than the zoom lens or may ultimately be much heavier.

Combining a realistic kit:

At 987 grams, it is 101 grams heavier than if you just carried the 24-70 F/2.8 GM.   But that doesn’t end the story.

The Sony A7riii weighs 657 grams.   If you pair the Sony A7riii with the 24-70 F/2.8 GM, the total weight is a neck stretching 1,543 grams.  When paired with the above-listed primes, the Sony A7riii camera-lens combination would weigh between 938 grams and 1,028 grams.   Your camera-lens will weigh considerably less with the prime lenses but your camera bag may weigh a bit more.

You should remember though, that you need not carry all 3 primes with you at all times.   If you know you are only taking short telephoto portraits, you may pack only the light weight Sony 85mm F/1.8.  If you are using the zoom instead of primes, then you are always stuck with the very heavy lens.

We can summarize by saying:

  • Primes give you a lighter body/lens around your neck at any given moment
  • Zoom lenses can ultimately result in a lighter total kit
  • Primes could still give you the lighter total kit as you don’t need to take every prime all the time

My Personal Path in Zoom vs Prime Lenses

The only thing clear is that there is no definitive correct answer.  That’s why some enthusiasts and professionals go towards zoom lenses and others favor bags filled with primes.

Sony 55mm at F1.8

Personally, I appreciate enthusiast level prime lenses.   With their faster apertures, they open up more possibilities and they are just fun to shoot.   For my uses, they offer superior image quality at lesser weight while a somewhat comparable price.

Yet, I suffer from G.A.S, Gear Acquisition Syndrome.   While I enjoy primes more than zooms, there are times when I do want the convenience of a zoom, especially when I don’t need a fast aperture.   Accordingly, you might find my final kit a bit wasteful:

This is not my entire kit, but it is my entire “normal view” range of lenses.   I would have saved a significant amount of money if I had simply gone with the Sony 24-70 F/2.8 GM but I wouldn’t be having nearly as much fun.   My camera would have been much heavier and I would be missing the image quality and creativity afforded by the 1.8 prime lenses.   The weight of my entire kit is heavier than if I had just gone with the 24-70 F/2.8 GM.  But I never carry the whole kit, just carrying the 2-3 lenses I intend to use any given day.   By mixing and matching instead of just using a single zoom lens, I have a lot more flexibility.  On the other hand, I will admit I sometimes miss shots because I can’t quickly change focal length without changing lenses.

When I absolutely need convenience, I do own the 24-105mm F/4.  You can find my review here.    For a zoom lens, it is indeed very good and I can recommend it.  It is finally in stock at Amazon.

The logic in this article applies equally to Canon and Nikon shooters (as well as any other brand).  But the specific pricing differences and lens options will vary by brand.

If you plan on purchasing any of the lenses discussed in this article, I would encourage you to use the Amazon links in this article.  It will not cost you anything more, but this site will be supported with a small commission.