How to Choose the Best Lens for You
by Jeff McLain
One of the most common questions we see on our various channels is: "What lens will be best for such-n-such?" As in, "What lens is best for family photos?" Or, "What lens is best for birds?" Or, "What lens is best for portraits?"
The truth is, outside of specialty lenses such as macro or tilt-shift lenses, the answer resides mostly with “it depends.” The lens choice you make as a photographer will rely on a few factors: Your intended angle of view, your desired depth-of-field, the level of ambient light in your scene, and "what’s typical." So, let’s break this down. . . (FYI - All numbers below are based on full-frame 35mm format.)
Angle of view
When you approach any subject with your eyes, you have a sharp area down the center of your field of vision, and then peripheral vision around that which is blurry. Most applications of the 50mm focal length are intended to be mimicking the field of vision of a human, omitting their outer peripheral out-of-focus areas, and these are often referred to as a “Normal” lens. At the 35mm focal length, the field gets wider, and wider still at 24mm. The lower the number, the wider it becomes until you get into "fish-eye" focal lengths such as 15mm and 8mm — known as Wide Angle lenses.
Conversely, as you move from 50mm and the number gets larger, you become more telephoto, with 85mm-135mm generally thought to be Short Telephoto, 135mm-300mm Medium Telephoto and longer typically considered Super Telephoto. But most folks just say “Telephoto” when it’s longer than 90mm.
In a nutshell, as you start out with a wide-angle lens, your subject will have to be very close to fill the frame. But as you move to longer lenses, your subject will have to be further away — which is why the 200-400mm+ focal lengths are ideal for subjects that are far away, like birds or football players.
In the images below, on the top left we start with the wider angle lens, where the distance to my face is very close. But as get to longer lenses, the camera has to move further away from my face to have me appear the same relative size in the frame. I’ve included the focal length and the approximate distance between the lens and my face in these images. Notice how the 24mm lens distorts my face. Compare that distortion to the 105mm focal length!
Angle of view is both a creative and technical choice — your creativity informs how you want to see the subject, but technical considerations may make you choose one focal length over another. Those technical choices usually revolve around how close you can get to your subject, how much depth-of-field you are requiring for the shot, and what amount of wide-angle distortion is acceptable for the image.
In the image below on the left, the wide angle is having a distorting effect on the top of the building. While still a cool shot by RMSP Graduate, Forest Woodward, in the context of professional architectural photography, you must be careful of distortion as this might not be acceptable to an architect. However, this sort of wide-angle distortion is acceptable in a lot of landscape imagery. Notice the effect of the wide-angle on the rocks in the foreground of this landscape image on the right by RMSP Instructor, Rob Gappert. As you get closer to objects with wide-angle lenses, those objects can distort along the edges of the frame.
Notice in Rob’s landscape the relative size between a rock in the foreground and the landscape on the far shore — the shoreline is much smaller in the image compared to the size of the rock, where in reality that same section of shore is much bigger than the rock!
When using a wide lens with products or still-life, you often will need to get close to the subject, or your subject will appear very small in frame. Wide-angle is typically not an ideal choice for tabletop product photography because that sort of work requires us to get at the subject to arrange or “style” it, or get lighting tools in real close — and if the camera is in the way, that’s a problem. Often, tabletop shooters will choose focal lengths closer to 50mm or short/medium telephoto like 90mm and tilt-shift, which I cover below. Anything longer and you run the risk of not getting the whole item in focus! Which brings me to: Your desired depth-of-field.
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Here’s the Rule-of-Thumb: The wider the lens, the more native depth-of-field. The longer the lens, the less native depth-of-field. In short, f/4 on a 24mm lens will have more in focus from close to far, than a 200mm lens will. The “in-focus” area of f/4 on a 200mm lens is a tiny sliver compared to what will be in focus on a 24mm lens. As the lens gets longer, the depth-of-field gets thinner. You could conceivably get an image that is sharp from foreground to infinity at f/11 on a 24mm lens no problem, but f/11 on a 200mm lens will never see the whole image in focus from foreground to infinity. But don’t fret! This can be used to your creative advantage!
When someone asks me “What lens is best for portraits?” The answer rests on the premise that portraiture is about the person, and not about their background — and therefore, you would want to render the background out-of-focus and the person nice and sharp, right? So, a 24mm lens wouldn’t necessarily be the best choice because the native depth-of-field on that lens is deep. You may be able to shoot them at f/4.0 and get the background out of focus a bit, but it won’t have the same creamy, buttery "bokeh" (the blur in the out-of-focus areas) that a 70mm lens or 135mm lens can produce at that same aperture, so a medium telephoto or telephoto lens would be a better choice for a portrait of someone if your creative vision wants to see them against an out-of-focus background — the traditional choice for portrait photography.
Examine this image below, shot at f/11 and then at f/4 and notice how much different the "bokeh" (out-of-focus background area), is. Notice how the wider aperture makes me stand out from the background, focusing our attention on the subject more.
Now, examine this series of images that depict the depth-of-field present with different focal lengths. All images shot at the same f/5.6 - you will see f/5.6 is not the same on all the focal lengths! Same can be said about all apertures – a given aperture does not perform the same on different focal lengths. The background is sharper in the wide-angle shots - and becomes softer as you go towards 200mm.
If I was shooting a large group of people, like at a wedding, for example, and I had people going left to right but also in depth, like a front row/back row scenario, my biggest considerations will be choosing a focal length that allows me to see them all in the chosen spot, as well as a focal length that has a good amount of native depth-of-field. 200mm would be a poor choice because it would put me across the street and unable to direct them all, and it would be hard to get them all in-focus due to reduced depth-of-field. I would choose a 35mm or 50mm lens where I can shoot at f/5.6 and get both the front and back row of people in-focus but still have the far background appear soft, which gets the group to stand out against the background. If I go too wide, then the people far-left and far-right will look like they are falling off the edge of the frame due to distortion, which is no good.
Specialty lens scenarios - Tilt-Shift and Macro
Specialty lenses are another topic. A tilt-shift lens will allow you to keep vertical lines straight up and down in an architectural photo, and also can be useful for technical focus requirements in a product shot, such as with the 90mm TS-E lens. I discuss this on YouTube in this video.
Macro lenses allow us to render an object at 1:1 magnification — such that if a small object measures 24.26mm across (like a quarter dollar coin), it will be recorded at 24.26mm across your 35mm full-frame sensor. This is called 1:1 and is the gold standard specification to look for in a quality macro lens. But because of this, and its medium telephoto focal length, these lenses have very shallow native depth-of-field and it would be very difficult to get total focus from foreground to rear with this type of lens. If you want to learn more about macro lenses, check out this You Tube video by RMSP Instructor Doug Johnson.
Photographers who have to shoot very small objects and render them in total focus traditionally would use a technical camera like a 4x5 to achieve this. Now, with advances in software, a photographer can do what is called Focus Stacking and shoot a series of images that focus through the object, and then the software can "stack" them into a final image that has critical focus from foreground to rear. This image of a Zoom F8n audio recorder below was shot with a medium telephoto lens at f/11 and because of the angle of the device, I was not going to be able to get the foreground front corner sharp and also the rear front corner sharp in one shot — so I stacked them to achieve maximum depth-of-field.
Ambient light and fast lenses
The last consideration is the amount of light available to you. Most folks shooting natural light will run into this technical consideration wherein the ambient light has fallen to a point where you don’t want to open your aperture up any more than your chosen f/5.6, but the ambient light is forcing you to slow your shutter speed into a dangerous zone for a hand-held shot. This requires that you raise your ISO. This is not as much of a consideration as digital sensor technology is improving and making it easier to achieve excellent image quality with extremely high ISOs, but it is still a concern if you are shooting in darker situations and you are in that dance between shutter speed being too slow, aperture being too open (narrow depth-of-field), or ISO being too high.
A "faster" lens won’t necessarily help a photographer in this situation. By "faster", I mean a lens that has an aperture that opens wider than the traditional f/2.8. In reality, if you need the depth-of-field of f/5.6, then you need f/5.6 — and having f/2.0 available to you isn’t going to help that depth-of-field situation. More ambient light, supplemental lighting, or the ability to have a high ISO are the things you would need.
This is what I refer to as Constants versus Variables. We’ll find these in our exposure triangle as well as when working with mixed lighting situations. In short, there are elements that are constant and unchangeable, and there are ones that you can vary. In the situation mentioned above, our shutter speed becomes a constant because with the lowering ambient light, we don’t want to go below 1/60th - so that becomes an unchangeable element. The ambient light, although it is changing quickly on its own, is a constant element, too, because we can’t control it. This leaves us with what we can change: the aperture or the ISO, (or adding supplemental lighting).
Another place we may experience this is working with mixed lighting. where you have fluorescent lights in a room that you can’t turn off, and there are too many to gel. And you need to shoot a portrait of a person with your strobe light, which is about 5600˚ Kelvin, but also see the room. The fluorescent lights have a nasty green tint and are the constant/unchangeable light source. In this situation, you can gel your strobe light with “windowpane green” to match the tint of the fluorescents, then adjust your color temperature on the camera to the fluorescent setting to match your light sources. So, Constants and Variables show up in exposure AND in color balancing situations that we often face as photographers.
OK, back to fast lenses . . .
Faster lenses help in situations where you are doing artsy portraits with very shallow depth of field. Imagine: You are shooting into dusk, and you find your exposure is at ISO1600, 1/60th of a second on your 50mm lens at f/2.8. And the light is falling into blue-hour and you are inspired and want to keep shooting these shallow depth-of-field portraits. However, on your particular camera you were diligent and ran a test to see how high of an ISO you could shoot at and not get noise, and because you ran this test, you know that your camera maxes out at ISO1600 before too much noise is present. You don’t want to shoot slower than 1/60th of a second because you could get camera-shake . . . and you’re at f/2.8.
Your ISO and shutter speed can’t be changed — they are your "Constants". In this situation, since you are already shooting at a very wide aperture, you will be able to keep your ISO and shutter the same by opening up your aperture to f/2.0 — this is your "Variable"! And if it keeps getting dimmer outside, you might be able to open up wider if your lens allows you to go to 1.8 or 1.4. Of course, your depth-of-field will be very shallow at this point, but this will be an aesthetic decision in that moment. Fast lenses are helpful to those who like that visual aesthetic and who shoot in dimly lit locations.
Fast lenses are very important to someone with shutter-priority in mind, like a sports photographer. If their exposure in a situation is 1/2000th at f/4.0 at max ISO — and the subject they are shooting really needs 1/4000th of a second to stop that action, and depth-of-field isn’t the primary concern — this is where being able to open up to f/2.8 on that same lens would be beneficial if they don’t have the room in ISO to raise it there. They can get their 1/4000th shutter with f/2.8.
You end up paying more for faster lenses. For example, the Canon 70-200 f/2.8L IS III USM lens is much more expensive than the 70-200 f/4L IS II USM lens, as it gives you one more f/stop of room to work, along with image stabilization ($1899 vs. $1299, respectively). Or, an even better example is to compare the Canon EF 400mm f/5.6L USM lens at $1149 to the Canon EF 400mm f/2.8L IS III USM lens at a whopping $11,999.00. You’re paying $10,850 for 2 extra stops of light and Image Stabilization! (Oh... but it’s worth it).
Fast lenses are also very helpful to videographers. When shooting video, the one constant you have that you can’t change is your shutter speed. At 24fps you keep the shutter at 1/50th of a second (on DSLR/mirrorless) and you only have ISO, aperture, and Neutral Density filters at your disposal for exposure. So, in that scenario, if you are shooting video in a dimly-lit situation and you are already at f/4.0, having the ability to get to f/2.8 or f/2.0 is extremely helpful. Digital noise becomes present when you raise the ISO too high in video files (again, camera dependent). And of course, if you have those very wide apertures on a wider lens, you’ll have more native depth-of-field than if you have those wide apertures on a telephoto lens. This is why most telephoto lens situations depend upon stopping action more than needing deep focus (e.g., hummingbird at a birdfeeder, horse race, football player, etc).
As mentioned earlier, there are genres where there is a typical "style" that informs the lens choice. Portraiture was traditionally short or medium telephoto lenses and a fairly wide-open aperture to get your subject to stand out. But, it depends! Perhaps you like shooting with one of these newer fast 50mm lenses at f/1.2 and you can get that same buttery bokeh from that shorter lens. Tilt-shift is typically the gold-standard for architectural photographers, but there are plenty of people out there shooting with regular 24mm lenses and using software to correct for keystoning distortion, for better or worse. And there are people using shorter lenses with sports and just getting their physical bodies closer to the action — such as when surf photographers leave shore and began paddling their cameras out into the waves with wide-angle lenses to get up close and personal!
You’ll notice I mention the word “typically” several times throughout this article. That's because these rules can be, and have been, broken. Your choices will be centered on what angle of view you want to "see" the scene with, and how much depth-of-field you, or your client, will require for the shot. Outside of those considerations will be how high of an ISO you can shoot at without digital noise on your camera system, and knowing that that ISO is your top-most threshold. That will dictate if you’ll need a "faster" lens or not. And those considerations all start with, “What do I shoot? And how do I shoot it?”
It depends! But if I were to give the short-list of recommendations, it's the following:
- Typically, landscape is shot with wide lenses: 17mm, 24mm, and 35mm. But Ansel likely employed longer lenses as he was trying to "reach across" large valleys for his portraits of famous rock faces from the roadside. So, it depends!
- Architecture is typically shot with 17mm, 24mm, and 35mm tilt-shift lenses.
- Group shots and documentary work usually run in the 35mm and 50mm range.
- Tabletop product is typically in the 50mm to 90mm range, and often employs tilt-shift lenses such as the 45 TSE, 50 TSE or 90 TSE.
- Food photography is also in that 50mm to 100mm range but can also take advantage of macro lenses or medium telephoto tilt-shift lenses.
- Sports and wildlife usually utilize longer telephotos like 200mm, 400mm, 600mm and on up. Unless the nature or wildlife is tiny, then you’ll need a macro lens!
- Wedding photographers shoot in a variety of scenarios like tight dressing rooms or out in nature — so a wedding photographer could conceivably get it all done with two lenses that cover the range: 24-70mm and 70-200mm.
- And portrait and family photographers can likely get everything they need in a 24-105mm zoom lens.
If you are looking at purchasing a lens, other considerations would be: if it is weather sealed or not, if it offers image stabilization, if it needs to be calibrated occasionally like the Sigma Art series, the size/weight of the lens, the reviews, the MTF chart, if it’s a “Pro” product like the Canon “L” series — and of course, the price.
I once asked one of the most successful and prolific stock photographers in the world who primarily shoots images of people and has an enormous catalog of imagery: “What lens do you use the most?” He responded, “I use the 24-70mm zoom on 95% of all my images.” Again, it’s all about asking yourself, “What do I shoot? And how do I shoot it?” and going from there.