[Pho.Talk] The Definitive Guide to Zoom Lenses

Zoom lenses, for quite a while in the history of photography, suffered from various myths and were often prejudiced for rendering subpar images.

While things have changed drastically today in how zoom lenses fare against its prime counterparts, it is still somewhat true that the quality of zoom lenses could fluctuate quite a bit.

In this article, we will look how and when professional photographers use zoom lenses, whether they are worth the investment, and what to look out for in choosing a zoom lens fit for your needs.

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What are zoom lenses good for?

Get a zoom lens if you shoot a lot while moving around, including travel photography, sports, news, wildlife, events, for example. The biggest strength of zoom lenses is the flexibility, allowing you to carry a range of focal lengths all in one. They come with a massive advantage of versatility when shooting under physical and time constraints.

With zoom lenses, the default is not to use them unless you need to zoom.

Zoom lenses do not come with any advantage in terms of optical quality as compared to primes, so you buy a zoom only if the type of work you do cannot be done on primes.

Here are some typical use cases of zoom lenses and why it makes sense:

  • Travel photography - you have your entire life fit into suitcases and therefore cannot carry much. You also do not know what to expect at a travel destination. Read my earlier article on Top Camera Lens Combinations for Travel Photography for how to travel smart.

  • Event photography - especially if you are paid to do this, you cannot afford to miss a shot on the shot list. The event space may be crowded and you may not know for sure how large it is.

  • Sports photography - you are tasked to photograph some of the fastest-running humans, whereas you are stuck at a fix spot. To get the framing you want, you ‘run’ with them via the lens.

  • News photography/ photojournalism - you are expect to shoot a bit of everything, and often find yourself shooting from an unfavourable location, under immense time pressure.

In short, zoom lenses come in handy in shooting situations where you have no control over your distance from your subject, or have to do a wide variety of shots under time constraint.

What are the disadvantages of zoom lenses?

Zoom lenses are heavier to carry around, because they are built with more lens groups. The technical difficulties of design and manufacturer put a higher price tag on zooms. Most zooms on the market open down to f/2.8 max, while primes go all the way down to f/1.2. In terms of optical performance, zooms are at no advantage over primes, if not a slight disadvantage.

Below I have provided an expanded explanation as to the reasons for each of the drawbacks. Comparative terms are used vis-a-vis prime lens.

Zooms are Heavier

In today’s market, given where optical technology is at, you will mostly find lenses to come in quite a few groups (g) and elements (e), abbreviated as xexg.

Number of elements tell you how many pieces of glass there is in the lens; number of groups tells you how many units they are placed into, because some elements can be jointed together to form a group.

Zooming massively increases the need for more elements in a lens, to counter the aberrations that arise from having to fit multiple focal lengths into one lens.

As far as correcting artefacts go, putting extra elements is usually the solution. The converse may not be true, as more elements can create another set of issues but that would be another story.

For this reason, zooms contain more layers of glass (or plastic on the lower end) and thus weighs more.

Here are the weights of some latest zoom lenses on the market today. Links bring you to Amazon if you would like to check out their latest prices.

Zooms are more expensive

Due to the higher level of complexity in build and design, zoom lenses sell for a higher retail price.

The kit lens that typically come with the camera body, as is the case with beginner level cameras, are relatively more manageable.

But if you are looking for a zoom lens that could be an absolute workhorse that you can rely on, they will cost you quite a bit.

I’ve chosen some example pairs of primes vs zooms below that open up to the same maximum aperture. Links bring you to Amazon for latest prices.

Generally, you can expect to pay the same price to get a high quality zoom, or a prime with 1-2 stops wider in maximum aperture.

Max aperture

As the aperture value lowers, the complexity of manufacturing a zoom lens increases exponentially.

This is why on the market, you never see zoom lenses that open up to more than f/2.8.

(If you do, DM me.)

Primes, on the other hand, free from the many restraints in relation to multiple focal lengths, are relatively easier to manufacture.

In the prime lens space therefore, there is generally more room for developing designs that has a maximum aperture of below f/2.8.

Most lower price point primes should go down to f/2.0 if not f/1.8.

Those that open up to f/1.4 or more start costing significantly more.

Slight decrease in optical performance

Today, this would probably be less of an issue among the top-tier zoom lenses because so much research has been put in that the image quality on the very best zoom lenses can finally be on par with that on primes.

Though this is still not the case generally because for one, these top lenses do not fit into the majority of photography lovers’ budgets and second, this category of zooms represents merely a tiny fraction of the entire population of zooms.

The greatest issue with having more elements and groups within a lens is that it increase the chances of unwanted glare and internal reflections.

These could lead to a reduction in overall contrast and sharpness of the resulting images.

As far as technology goes, zoom lenses are no longer at a definite disadvantage when it comes to image quality. But they are definitely not an an advantage either.

What to look for in choosing the best zoom lens?

Focal length range

Different types of photography will require a different focal length range.

Sorting this bit out first is a great way to narrow down your list of lenses to consider massively.

Here are some typical use cases of zoom lenses at various ranges.

Below 24mm

These are ultra-wide lenses that can be stepping into fish eye territory.

You will most certainly see significant distortion of the images, not only around the edge; the artificial elongation of subjects will become noticeable from the outer two-thirds of the frame.

Sample image taken at a focal length of 21mm.

But on the bright side you will be able to include a lot in the frame, even if standing at arm’s length from your subject.

This image, for example, was taken at a focal length of 21mm.

While it isn’t quite the fish-eye look yet, you can definitely see a great deal of distortion.

Obviously in the edges, which would be the case for most wide lenses.

But the effect remains highly visible and in this case, barely eases only towards the other end of the street.

This category of lenses are not widely used because of this very specific look that it gives.

But I have seen photographers resort to ultra-wide lenses where it would be impossible to step back from the subject, and sometimes purely because of artistic discretion.

If you would like to get one of these lenses, consider the list below. Links bring you to Amazon for latest prices.

  • Canon EF 16-35mm f/4L IS USM - Great lens if you would like to venture into the fisheye territory while also being able to shoot normal wide, on the 24-35mm end.

  • Nikon AF-S NIKKOR 14-24mm f/2.8G ED - this is a high end lens that opens up to f/2.8 at ultra-wide focal lengths, while still delivering excellent sharpness edge-to-edge. Very reasonably priced for its calibre.

  • Sony FE 14-24mm f/2.8 GM - while also highly competent, the Sony version is priced at a much higher premium than that by Nikon.

24-70mm

This is usually regarded as the everyday zoom range. 24mm belongs to the wide end, and 70mm belongs to the short telephoto end.

In the middle you have the 35mm and 50mm focal lengths, which are widely acknowledged to give a vision closest to that of the human eye.

In simple words, lenses in this category have you covered in everyday situations.

This would be a great option if you are looking for a travel lens, as I explained in my earlier article Top Camera Lens Combinations for Travel Photography.

This is also the go-to lens for press photographers covering news.

Event photographers will most likely also have a zoom in this range in their camera bags.

If you would like to get one of these lenses, consider the list below. Links bring you to Amazon for latest price updates.

70-135mm

Lenses with focal lengths in this range fall into the short telephoto category.

Distortion of frame edge tends to reduce to basically negligible - you can expect to see vertical structures render as almost perfectly vertical in the image, likewise for horizontal ones.

Lens compression also kicks in at this point at and becomes exceptionally noticeable - the perspective appears flatter and things appear closer to each other in frame as compared to in reality.

Based on this profile, if you foresee yourself shooting quite a bit of portrait work, this focal range will work wonders for you.

If you enjoy the ‘flat’ and ‘neat’ look, this range of focal lengths is what you will use to get that vision, without having to carry an absolute beast that kills you over longer distances.

If you would like to get one of these lenses, consider the list below:

  • Canon EF 24-105mm f/4L IS II USM - With this lens you are paying for the extra reach in terms of distance, which is a very practical consideration, rather than artistic concerns.

  • Nikon AF-S NIKKOR 24-120mm f/4G ED VR - this is perhaps the best deal you can find among the bunch of Nikon lenses in the similar zoom range. Best compromise between extended zoom range and maximum aperture.

  • Sony FE 24-240mm F3.5-6.3 OSS - This lens has a very special place in the market and imo it is a genius idea, surprisingly humbly priced. On the tighter end, you are able to zoom in two times greater than what the market typically offers (like above); and it is so compact that it is unreal.

200mm and above

These lenses are categorised as telephoto lenses.

Based on my experience, shooting at short-tele to telephoto focal lengths result in slightly more surreal images - after all, these are fields of visions that you are not able to see with your naked eyes.

But unless you are specifically looking to play tricks with the flat, compressed look, these lenses are mostly for situations in which you need a reasonably tight crop of your subject but can only shoot from a distance.

Typical examples of this would be wildlife. The animal of interest may be dangerous therefore it is not plausible to photograph up close; the animal might be particularly sensitive to sound and you would lose the shot had it been disturbed by the camera shutter or any general sound of humans being around.

Another example would be sports. Quite obviously if you go up close to photograph the athlete you will be in their way, and also cause distraction.

For large scale sports competitions, photographers are assigned a press pit and that’s all they are allowed in. They will usually have to shoot from across the entire venue, but obtain half-body shots of athletes.

This can well be the case in landscape photography, where you find something interesting for instance in the middle of a lake that is not possible for you to cross, or on the zenith of a neighbouring hill.

If you would like to get one of these lenses, consider the list below. Links bring you to Amazon for latest prices.

  • Canon EF 70-200mm f/2.8L USM - Canon has to date released three (similar) versions of this lens, this being the first generation recommended here. The reason is that while this version does not offer image stabilisation, which can make a ton of difference at the professional level, this should be a good entry-level experience if you would like to dabble with this focal length, at a fraction of the price of the third-gen version.

  • Nikon AF-P NIKKOR 70-300mm f/4.5-5.6E ED VR - Again, assuming that low light performance is not a necessity, this lens is gives you a whole lot of bang for your buck.

  • Sony FE 200-600mm F5.6-6.3 G OSS - A zoom that reaches 600mm in focal length is unheard of in the market; Sony is the only manufacturer to have this capability as of now.

Max aperture

Most kit lenses have a maximum aperture of f/3.5-5.6, meaning that it can open up to f/3.5 at its widest focal length, and only to f/5.6 at its longest focal length.

In terms of letting enough light in, these lenses mostly do fine during day time outdoors.

But they tend to not make the cut if shooting indoors and at night; you will have to use a ridiculously high ISO which will result in barely useable photos.

To shoot at night with greater ISO flexibility, f/2.8 is the least you will need, and pretty much the industry standard as I explained in my earlier article How Pros Shoot Night Photography on Streets without Tripods.

In terms of artistic requirements, they will also not give excellent bokeh or background blur.

Based on my experience, the buttery, smooth background blur starts becoming more pronounced at the f/2.0-f/1.8 range. The lower you go, the more pronounced the effect becomes.

Sharpness (center and edge)

There are two parameters when it comes to measuring the sharpness of a lens: centre sharpness, and edge sharpness.

All lenses demonstrate a decrease in sharpness from the centre of the frame to the periphery; it is just a matter of how drastic the fall-off.

For the purposes of most photographers, centre sharpness is really what matters because you mostly place your subjects towards the centre of the frame anyway.

But in the case where large blow-up prints or presentations are required, edge-to-edge sharpness becomes a critical consideration.

I shall not go in depth into how to assess the sharpness of the lens here, but I can point you in the direction of what to look.

Whatever lens you are looking to study, search for its 'MTF graph, short for ‘Modulation Transfer Function’.

A highly-simplified account is that you look for 1) how much the line drops towards the right, and 2) at which point is the drop most rapid.

These two things tell you 1) if the edges are going to look good, and 2) if the sharp area is wide enough for your use.

Ideally you should compare the MTF graphs of the few lenses you are thinking of buying. You will quickly be able to get a rough sense of what you are getting out of with your money.

Weight

Weight is a huge consideration, despite it having nothing to do with the image quality of the lens.

You should only carry how much your body can physically take.

I have learnt this the hard way - carrying too much gear out of FOMO walking over long distances and extended periods resulted in muscle tears, in turn becoming a recurring injury.

So make sure you listen to your body when it comes to buying a lens - buy a lens that, when combined with your camera body, is of a manageable weight, even if that means spending more.

This is typically the case with third-party manufacturers - they are often able to come up with lenses at a fraction of the price of the native lens, but often bulkier.

Nothing costs you more than a sustained injury, which tends to develop over time among certain genres of professional photographers.

Budget

Personally, I tend to not skimp on lenses.

But this is because I make a living with my photos; lenses are a critical factor that impacts how my images look. Saving money on lenses but get sub-par image quality is therefore not a smart trade-off.

The considerations are obviously different if photography is a hobby for you and you have no intention to make money out of it in the short future.

If you are at a stage where you have not decided which camera system to stick to in the long run, I would advise that you go with mid-range lenses and avoid those in the highest price point; lenses only become valuable investments once you are set on a camera system, as I explained further in my earlier article Guide to Investing Smart in Lenses and Camera Bodies.

What is the difference between a zoom lens and a telephoto lens?

They are different groups of lenses by definition, though some lenses fall into both groups. Zoom lenses refer to lenses that enable the photographer to shoot with varying focal lengths. Telephoto lenses refer to lenses that are physically shorter than their focal length. The two definitions represent different ways of classifying lenses although in practice, especially at longer focal lengths, lenses are often both zoom and telephoto.

Do not conflate the two - zoom lenses and telephoto lenses are not opposites, and do not share much of a relationship.

They are two distinct ways of categorising lenses and are therefore not two ends of the same spectrum.

Zoom lenses are relatively straightforward - any lens that allows the photographer to vary the focal length falls into the definition of a zoom.

Telephoto lenses, on the other hand, require more of an explanation.

The textbook definition of a telephoto lens is a lens that is shorter than its focal length. Some lenses fall into this category obviously because of the sheer length of their focal lengths - of course you wouldn’t have a 400mm lens on you (that’s 40 cm fyi).

Because of this, the word ‘telephoto’ is often used interchangeably with ‘long’. Generally, we call any focal length above 70mm telephoto.

But technically, this is not always true. There are lenses with focal lengths longer than 70mm that isn’t telephoto, and shorter lenses that could turn out to be telephoto.

Without getting into too much detail, I hope you see the relationship between the two, being that there are none.

Zoom lenses can happen to step into the telephoto focal length territory, but it may or may not happen.

Conversely, telephoto lenses may or may not be zooms.

There are no fixed correlations between the two.

Do pros use zoom lenses?

Yes of course! There are genres of photography that almost have to be shot using zoom lenses, because prime lenses are not going to provide the degree of flexibility required. These are typical of sports, news, wildlife and event photography, where professional photographers find themselves working under immense time and spacial constraints. High quality zooms are always in demand among pros.

There used to be a widespread belief within the photography community that professional photographers do not shoot on zooms because the image quality will suffer as compared to primes.

This could have been generally true decades back but today, the same cannot be said of zooms.

As I have laid out above, while zooms are generally plagued with more issues, the best zooms on the market today are on par with what you can get on the best primes.

Budget is the price, given that it is much more difficult to make a fine zoom than a prime.

But from the perspective of professionals, where money is the issue, there is no issue. Of course you invest into your business - and especially when you are paid to buy the gear anyway.

Are zoom lenses worth it?

Definitely yes if you do photos for a living or aspire to create a career out of it, full-time or part-time, which means it would cost you quite a bit to miss a shot. It is debatable whether to pay a high price for a zoom upfront if you can afford to miss some shots, as is usually the case with hobbyist and beginners.

Those who are already pro

If you are reading this, I assume that you are not yet a full-time photographer or making a substantial amount of money out of photography because if you are, you most likely are not asking this question in the first place - the answer would be straightforward, that is to buy the gear.

Those who are hobbyists

This situation is also similarly straightforward for anyone who is a hobbyist and do not aspire to turn it into their profession. In this case, stick with what you have until you absolutely can’t make it work anymore.

This is a great rule of thumb generally; it forces you to learn as much as you can about your gear.

Those who want to turn pro

For those who are pro-consumers who are thinking of getting into the industry, the line can be less clear-cut.

Based on my experience, of turning into a pro from a pro-consumer, I learnt that you will have to get your gear up to industry standards before you will be able to get your feet in.

It can be a difficult decision especially if you are in a lot of financial pressure, as is usually the case with early career photographers.

But it is not a matter of buying or not, because if a zoom is what you need for the type of work you do, you will need it even if someone hands you a job right now.

So my advise is to research on what other photographers in your field are using, save up for it, and buy it at your earliest convenience.

What is a good zoom lens size?

The biggest lens that you should buy is the one that you can realistically carry for the duration of your photo sessions. Unless you are in a specific area within photography in which case your choice of lens is pretty much limited, where you get to chose, go for a lens no heavier than your body could take. The general advise is to avoid lenses over 1kg, it not meant to be used on a tripod.

This recommendation would, of course, apply better to some than others, and I am speaking from the perspective of an average woman.

But as I explained above in relation to the inherent extra weight zoom lenses come in, as compared to primes, zooms can really start posing health issues to photographers generally.

If you foresee yourself having to walk over a long distance carrying the lens and on a regular basis, it would almost always be worth it to pay a premium in exchange for a lighter lens.

You can photograph only so long as your body is up for the job! No lens can cost more than your health, truly.

Summary

In this article, we talked about:

  • What zoom lenses are good for;

  • The disadvantages of zoom lenses;

  • What to look for in choosing the best zoom lens;

  • The difference between zoom and telephoto lenses;

  • Whether pros use zoom lenses;

  • Whether zoom lenses are worth it; and

  • Good zoom lens size

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