While buying the camera itself and especially afterwards, it is often difficult to know exactly what to do when considering buying a lens. What do all of those technical characteristics mean? What is the best lens to suit your budget? What type of lens do you actually need? What is a fixed focal length lens? Basically, you probably have thousands of questions and I will try my best in this article to answer some of them.
This is actually an ideal moment for me to do this since two of my friends asked me for advice last week regarding photographic equipment, and I myself bought a new lens (which I will undoubtedly speak about in detail once I have had enough time to play around with it ).
Above all, I don’t want people to think that I am contradicting myself: I still think that the purchase of equipment should not be your main priority. If you have problems with your photos (lack of sharpness, colors, or anything else), it is probably due to something that you are doing rather than to the equipment that you are using. However, when you start to get to know the kinds of subjects that you are interested in photographing, you may develop special needs. Or, if you feel limited by your equipment, you can always expand your capabilities by acquiring a new lens.
As usual, it must be your needs that determine the equipment that you buy. This article attempts to be a complete guide for helping you make your choice, but it will not make the choice for you An of course, it is valid for all brands!
Given the number of existing lenses, it is understandably complicated to find your way through this jungle of products. Let’s begin by specifying something which may seem obvious, but which may nevertheless be helpful: it is not possible to mount a Canon lens on a Nikon camera, or vice versa. However, there are two, third party brands (Sigma and Tamron) which offer versions of their lenses for practically all existing brands of cameras.
Now let’s look at each of the different parameters that you should take into consideration:
This is usually the first bit of information that you will see when reading the description of a lens: the focal length is expressed in mm – for example, 50 mm or 18-105 mm. This number indicates to what extent your subject will be enlarged (or reduced in size) relative to your vision while taking a photo. The focal length parameter allows us to distinguish between two different types of lenses:
· Standard: means that what you will see through the lens will correspond, more or less to what you would see with the naked eye. For technical reasons – which I will not get into right now – the focal length of the human eye is around 50 mm for a film camera or a full frame format camera (two types of cameras which you probably don’t own), and 35 mm for an entry or mid-level reflex digital camera. As a result, this category contains all of those lenses with a focal length ranging from around 35 to 85 mm.
This type of lens is generally ideal for taking portraits or “a little bit of everything” photos. Furthermore, the lens that usually comes in the kit with a camera is an 18-55 mm lens – which falls into this category and to some degree the next one – which is perfect for taking vacation photos or pictures of your mother.
· Wide-angle: this category gets its name from the fact that the scene that you will see through this type of lens is wider than what the human eye sees. This category generally includes lenses of a focal length of 28 mm or less. This type of lens is often used for landscape photography where the goal is to capture as much of the scene as possible. Since there is a tendency when using this type of lens to get closer to one’s subject, there is an increase in the impression of depth of the captured images as well as in deformations due to perspective.
There are also very wide-angle lenses which greatly deform the image called “fish-eye” – due to the resemblance that the bear to a fish’s eye. But, these are very specialized lenses and are generally not a priority for photographers.
· Zoom: this category contains all those lenses with a focal length in excess of 100 mm (lenses with a 300 mm focal length or higher are called super-zooms); this type of lens is used to fill up a frame with the subject even from a great distance. As a result they are frequently used in sport and nature photography. Some small zooms – around 100 mm – can be used for portraiture.
From left to right: a wide-angle (10-22mm), a standard with a little wide-angle (15-85mm) and a telephoto lens (100-300mm)
I hope that these 3 simple categories have already helped to clarify things for you. Now let’s speak about 2 points which are intimately related to the focal length.
Minimum focusing distance
At the same focal length, let’s say 50 mm, an ant will not be the same size on the photo if the picture is taken from 50 cm away or from 5 cm away – that seems fairly obvious. Here is where the minimum focusing distance comes into play: only macro lenses allow you to focus at a very short distance away from a subject in order to fill the frame with it – like the ant in our example. Therefore a lens is considered to be macro if it has this characteristic which does not have anything to do with the focal length: there are macro lenses with a focal length of 50 mm and others with a focal length of 200 mm.
Zoom or fixed focal length?
To simplify things: a zoom has a variable focal length whereas a fixed focal length lens obviously has a fixed focal length. You might be thinking: “Fixed focal length lenses are dumb, you need to walk to get closer instead of just zooming!”. How lazy are you?! I am generalizing a bit since there are good and bad lenses in the two categories, but let’s take a look at their respective advantages:
Advantages of fixed focal length lenses
- Quality: zooms have been getting significantly better, however for the same amount of money, a fixed focal length lens produces clearer and more precise images, with more sharpness than zooms. This is not always the case, but it does have some validity as a general rule.
- Price: fixed focal length lenses are, generally speaking, cheaper – which is logical since they are of a simpler construction (they do not have moving parts for zooming). Obviously, there are also very expensive fixed focal length lenses in professional product lines. Entry-level 50 mm lenses are known for being extremely affordable while offering very good optical quality.
- Weight: since they are of a more simple construction, this type of lens is generally lighter than a zoom, which is not a negligible factor after a long day of walking on a holiday outing for example.
- Maximum aperture: generally speaking, fixed focal length lenses have a wider maximum aperture than zooms, we will speak more about this point later on.
- Creativity: this is a more personal and less objective factor, but by forcing you to move around in order to correctly frame a scene, a fixed focal length lens requires you to be more creative in order to choose other angles from which to shoot.
The advantages of zooms
- Versatility: Zooms cover a wider range of focal lengths, they allow you to take several different types of photos. And, depending on the lenses that you normally carry with you in your camera bag, they can even be advantageous in terms of weight and cost.
- Flexibility: Depending on the range of focal lengths that it covers, a zoom can allow you to take wide-angle shots, standard shots as well as zoom shots with the same lens! I’m thinking in particular about the “trans-standard” 18-200 mm type lenses.
This article may already seem long to you, but there are many factors to take into consideration, and we are talking about the way in which you are going to spend your next Christmas bonus after all. Preparing in advance for your next purchase could end up saving you a few bucks. But don’t worry, the rest of this article will be shorter!
First of all, if you still don’t know what this is or if you need a refresher, go back and read the article on aperture before continuing. The maximum aperture is expressed by a value in the form of f/number, and determines the extent to which the lens’s diaphragm can open. Meaning that the greater the maximum aperture (and the smaller the f value, remember):
- the more you will be able to take photos in low light conditions without lowering your shutter speed, increasing the ISO sensitivity or using a flash
- the more reduced your depth of field will be
Depth of field is a very interesting aspect from the point of view of creativity, and I can tell you that until you have taken a photo at a setting of under f/2, you won’t really know what depth of field is.
But the ability to take photos in low light conditions is a major advantage which should not be neglected! This is why lenses with a wide maximum aperture are called “luminous” (they allow more light to enter) or “fast” (they allow you to use faster shutter speeds).
You should be aware of the fact that these advantages generally translate into a much higher price, especially for zooms and/or long focal length lenses.
The maximum aperture value appears after the indication of focal length among the values indicated on a lens. Here are three examples to help you better understand:
- 50 mm f/1.8 means that this is a fixed, 50 mm focal length lens which has a maximum aperture of f/1.8
- 18-55 mm f/3.5-5.6 means that this zoom’s diaphragm can open up to f/3.5 at 18 mm and up to f/5.6 at 55 mm
- 28-70 mm f/2.8 means that this 28 to 70 mm zoom has a maximum aperture of f/2.8 regardless of the focal length
The maximum required aperture depends on the situation in which you are taking photos:
- Indoors, especially in very bright situations (I am thinking about concerts), you will need an aperture of f/2.8 or more.
- On overcast days, especially in conditions requiring a fast shutter speed, you can get away with an f/3.5 or faster.
- In full sunlight, any type of aperture will do.
At this point, you have become aware of the two main elements which will determine your choice of lens: focal length and maximum aperture. Now let’s take a closer look at the other details.
Stabilization prevents motion blur (which occurs when your camera is not stable), and is therefore not very useful when using a tripod for example. Stabilization is very useful when you are using a lens with a very long focal length – which will be more subject to motion blur.
This technology will allow you to reduce your shutter speed by up to two notches (or maybe even more) without encountering the motion blur problem – which can be very useful in low light situations.
Stabilization is not trivial. As a matter of fact it is because of this consideration that I recently recommended to a friend that he not make the purchase that he was considering: an attractive offer on an 18-55 mm lens without stabilization – which has a poor reputation, and a 75-300 lens with which he would only have been able to take clear photos in ideal light conditions (which never happens when you need it to, obviously).
There will be bad lenses produced by your camera’s manufacturer and there will be good lenses produced by third party manufacturers such as Sigma and Tamron, and vice versa. My principle is simple: I look for a lens from my camera’s manufacturer (Canon in my case). And, if I can’t find what I’m looking for, I look for a lens from a third party manufacturer.
For certain models of lenses, you may prefer to choose the third party alternative when the difference in quality is minimal, but the difference in price is significant. It is up to you to read the tests available on the internet in order to decide whether or not there are significant savings to be had.
This is obviously the most important limitation for many of us. I am not going to lie to you: generally speaking you get what you pay for, and an inexpensive lens will usually be less good than one from a superior product line, it’s only logical. But the important thing is the relative price! Let’s take an example: a 50 mm f/1.8 costs around one hundred euros, and nevertheless, it is a good lens with a wide maximum aperture and excellent crispness. It is very affordable since it is of a very simple design and is built from inexpensive materials. There are two other lenses in the same product line – both of which are 50 mm fixed focal length lenses – one of which opens to f/1.4 and sells for 4 times more and the other to f/1.2 and sells for 15 times more.
Let’s summarize what we have discussed. Depending on your needs, you will have to determine:
- the focal length that you require: wide-angle, standard, zoom
- if the lens needs to be flexible (zoom) of if that is not an indispensable consideration (fixed focal length)
- if you need to be able to focus at close distance (for macro photography) or not
- if you require a wide maximum aperture, meaning whether or not you will be taking photos in low light conditions
At this point, you can begin to determine 2 or 3 lenses that suit your budget, or decide to continue to save you money (I’m not joking, that is an option). Read the tests conducted on specialized internet sites by doing a Google search, as well as user feedback on forums. At the end of all this you should be able to make your choice!
That’s it, I didn’t think that this article would end up being so long, but the subject is vast, especially when trying to satisfy all types of needs and attempting to speak about all the available brands! If you have any questions or comments, please don’t hesitate to leave them in the comments section below.