It seems to me that the general idea is that, once you start getting to become a decent photographer and are really moving beyond your kit lenses, you shouldn't be looking at anything slower then f/2.8

Is that the case? When is it acceptable to buy a high quality lens that is slower then that, other then for really long telephoto (at which point buying f/2.8 becomes stupid expensive). Or should you always try and stick to f/2.8 or faster?

In response to some of the answers given so far, would a better question be "for which types of photos/situations can you get away with using the f/4 version of a lens instead of the f/2.8".

For example, in my (limited) knowledge, you'd definitely want to use the f/2.8 for portraiture and sports, while an f/4 would be enough for landscape and architecture photography.

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    If are encountering a specific problem, then please ask it directly. This kind of vague question is not constructive and I suspect answers would be as generic. Mine would be buy what you need. – Itai Nov 19 '12 at 19:59
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    I don't think it's that terrible of a question. We do all sorts of myth-busting here, and this is certainly something I've heard from people On The Internets. – mattdm Nov 19 '12 at 21:11
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    The real question this is converging to is Why are there apertures smaller than F/2.8? ;) – Itai Nov 19 '12 at 23:59
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    I agree with @mattdm, this question is great for myth-busting here. – John Cavan Nov 20 '12 at 0:24
  • Weight can be a huge factor when you shoot for 12 hours straight, climb a 500 meter high mountain etc. Working female photographers are usually more concern with weight and constantly using heavy equipment can actually injure photographers that are not physically strong(male or female). – Gapton Nov 20 '12 at 3:38

11 Answers 11


Many many reasons exist to buy lenses slower than f/2.8.

  • Price
  • Size
  • Specialty lenses
  • No need for a wide aperture
  • Versatility
  • Compromise over above factors

As you suggested not all types of photography require wide apertures. Landscape photographers oogle over the Canon TS-E 24mm f/3.5 L II Tilt-Shift Lens for example. It is f/3.5, costs around $2,000USD, and is of extremely excellent quality in all regards.

Another reason is simple "business sense". A pro doesn't buy f/2.8 just to buy it, they buy what they need to make images as their clients and work demands. You might be able to use a 70-200mm f/4 IS lens to get excellent images. Would spending $2,000 USD on a f/2.8 version of that lens produce more income for a professional? That is a question they would have to ask themselves before simply spending money for a heavier and bigger lens.

Versatility is a big one. Take for example the Canon EF 100-400mm f/4.5-5.6 L IS USM Lens. It is extremely versatile. Could you get the big 100-400mm in a f/2.8? Possibly, but I doubt it would ever be this size or image quality. The tradeoffs are worth it in this case to have such a focal length range. You aren't going to be shooting indoors with low light with this lens, but that isn't what it is for.

Regarding Your Edit

You can "get away" with slower lenses doing just about anything. You are just going to have to bump up the ISO, potentially use a tripod, flash unit, or multiple exposures to get a shot. Can you shoot sports indoors at f/5.6 without a flash and with a camera that is poor at high ISO performance? Probably not very well, but you can probably do it. But you probably can't shoot very great photos with a poor high ISO performer, no flash, and a lens that is only f/5.6. Take for example a current smartphone. Can they "get away" with capturing an image even in poor lighting and poor effective apertures, yes. But the results are poor.

  • It's worth noting that slower objective may deliver better resolution, low speed tilt shift objectives being part of examples. – Euri Pinhollow Mar 22 '16 at 6:36

Canon's 70-200 f/4 L lens is a perfect example of a lens slower than f/2.8 that has a niche even when an f/2.8 equivalent is available. Comparing the f/4 lens(s) to their corresponding f/2.8 cousins, the f/4 lenses are around half the weight (not to mention half the cost), which makes a real difference to some people if they're carrying the lens around all day.

  • How much image quality are you sacrificing for that reduction in weight and cost? – Taylor Huston Nov 19 '12 at 21:00
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    @TaylorHuston - the Canon 70-200 f/4 is known for it's amazing sharpness and image quality, so, while the f/2.8 is better, in practical terms you're not sacrificing image quality - just low light capabilities and depth of field control (and f number does not indicate image quality, just the size of the "hole" in the lens) – Nir Nov 19 '12 at 21:45
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    All of Canon's 70-200 L lenses are very highly respected. I think you're talking about the difference between "excellent" and "really excellent" across all the 70-200 L's. Bear in mind that there's an IS and non-IS version of each, and the f/2.8 pair is now in its 2nd version. The f/4 II currently exists only in the rumor mill. In any event, that's a lot of really nice lenses. – D. Lambert Nov 19 '12 at 21:46
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    @TaylorHuston None. The image quality between the f/4.0 and f/2.8 are very close, and they both produce very, very sharp images. Weight reduction can be extremely important when you have a 12 hours event to shoot, or a mountain to climb, or if the photographer is not physically fit/strong. I am 6 foot 2 and carrying a 70-200 f/2.8 with flash for just 10 hours was harder than I think. – Gapton Nov 20 '12 at 3:32

When I was doing online photography course, the photographer who wrote it was specialised in food photography. At some point he admitted moving from lens with f2.8 to f4 explaining it by the change of his style of shooting. Before he liked food having very shallow DOF, and now he wanted to show more details.
I am shooting food for stock and almost never use such shallow DOF as f2.8, so yes, food is one of the subject where pros might want go for f4 lens.

BTW, I don't think all the pros use f2.8 for portraits, especially in studio and with telephoto lens as sometimes more than just eyes need to be in focus in portrait. For example fashion images outside, where environment needs to be included, f2.8 wouldn't work.

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    FWIW, I rarely went wider than f/5.6 in studio portraits when I was a pro. This narrow DoF portrait thing is a recent trend, and really doesn't work even now for all applications. We used to like fast lenses for focus accuracy and viewfinder brightness, but autofocus (and EVFs/LCD screens) make that a lot less important now. – user2719 Nov 20 '12 at 23:30

There is more than just lens quality, depth of field control and low light shooting ability to consider. For some applications size and weight are important or perhaps a convenient zoom range in one package. As @Itai said "buy what you need". My kit consists of several fast primes but I also have a 24-120 f4 zoom. I have that lens because I wanted something smaller than a 24-70 f2.8 (or equivalent). I carry that lens on my camera in a small shoulder bag pretty much everywhere I go. For me it is the right lens for the job of "I have a camera with my at all times". Others choose a compact camera for that job. I feel the 24-120 f4 is a good compromise the range is 24 on the wide side because I care more about wide angle than telephoto and the 5 times zoom has better quality than some of the uber zooms. I give up the fast speed to gain a lighter lens.

I bought what I needed.


Lens design is always a matter of choosing the right balance between a number of factors. Maximum aperture is one, of course, but others are size, weight, distortion, micro-contrast, evenness of field, zoom range, curvature of focal plane, chromatic aberration, spherical aberration, and more — including, of course, price.

Pushing a lens to a fast aperture requires compromise in the other areas. Even when cost is no object, you may prefer a smaller, lighter lens.

The Pentax DA Limited 15mm f/4 is an example of this in action. At around $650, it's a medium-priced lens, but it gets strong reviews. It's a stop slower than, for example, the Canon 14mm f/2.8L, but it's a third the weight and a fraction of the size. The Canon lens (as a pro-grade "L" model) can gather more light, and is certainly technically better (read: makes fewer design compromises), but it would be something I'd only take along were I expecting to want a wide angle. The Pentax lens just nestles into a corner of my camera bag, just in case.

(That's not meant to be a Pentax advertisement; I'm just comparing two lenses I know. The Pentax DA 14mm f/2.8 would be another choice, but it's not nearly as nice as Canon's.)


Some times we have a f2.8 or two already and don't need all lenses f2.8. Because of weight. size and cost.

I'm using a 5Dmk3 and currently use a 40mm f2.8, 100 f2.8L and 70-300L so I really don't need a 24-70 f2.8L unless I was a full time Professional and I'm not. Only studying less then 3 years Photography full time. Yes f2.8 and faster lenses are easier to control bokeh and or dept of field in most situations. but we learn ways around this when we have no choice such as bringing your subject closer and background further to achieve similar results. And believe it or not most pros use artificial lighting and prefer to keep ISO lower where a f2.8 only helps with one stop as Flash work to several stops when used properly. I already ordered this lens the f4L to complete my range of 24-70 FF with my 5Dmk3 and will love the added contrast, weight savings, sharpness, macro capability and much more at a savings. Because I know how to use my tools.


A wide aperture lens wont necessarily be the sharpest lens, and when it comes to most landscape photography sharpness is much more important than aperture as most shots will be taken at apertures of f/5.6 - f/11 to increase depth of field and sharpness.


It isn't always about speed. I do a lot of work at f8 or so and would love to go even more closed but diffraction creeps in.

I do submit that some famous names, part of Group f.64, have achieved artistic success.

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    Thus raising the question: Why would a serious photographer buy a camera with a film size smaller than 4"×5"? :) – mattdm Nov 20 '12 at 13:18
  • I have a friend who would agree with you! Keeps on wanting to lend me one of his 4x5s. But developing! Ugh... not sure I can handle that... – Paul Cezanne Nov 20 '12 at 14:36
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    I'd argue that for some types of photography (certainly not all), a "serious" photographer would probably be using a medium format camera where an f/2.8 or faster lens is only an option on the "normal" prime. And if you're using a technical camera with an MF back, your fastest lens is likely an f/5.6 Digitar or Digaron. – user2719 Nov 20 '12 at 23:25

I think the answer depends mostly on cost. A serious photographer may not be a rich photographer! Most fast lenses are expensive compared to the slower equivalents, so in the end it all boils down to how good an image do you need and how much can you pay for it.

  • I think cost is just one of the factors. Cost is important, but those f/2.8 zooms are huge. – mattdm Nov 19 '12 at 21:53

People have already mentioned image quality as well as size and cost, but there's another very simple reason: sometimes you want a huge depth of field.

Landscape photography is often shot with a very closed down aperture; f/4 is hardly a common landscape aperture size. Street photography is almost always shot at very narrow apertures for DOF reasons.

Just because you can shoot at wide open apertures doesn't mean it's always desirable; it's just that many beginners end up with lenses that don't open very wide, and automatically think wide aperture == more expensive == better.


Why would a serious photographer buy a lens slower than f/2.8?

Because a EF 400mm f/2.8L IS USM II costs $10,000 while a EF 400mm f/4L DO IS USM costs $3000.

Because they don't make a f/2.8 version of the world's widest fisheye zoom.

Because you only need f/2.8 if you're actually shooting at f/2.8.

And because expensive equipment doesn't make you a better photographer.

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