Basics:
The topic of this tutorial is camera lenses, what do they do and how do they effect photos. A common phrase that you may hear is ‘you should marry your lenses and date your cameras‘. The point of this phrase is that lenses are incredibly important to the photography process, and when you’re starting off often it is implied that if you get a certain camera, you’ll be able to get the images you want, but in reality choosing the right lens is often more important to get the photos you may like and hopefully in this crash course on lenses I’m going to help you get started on getting understanding on how lenses are named and how to pick the right one for yourself.
I am going to start off with the fundamentals of what lenses do, and what the numbers in the names mean. Lenses focal lengths are measured in millimeters, and to simply put it, the smaller the number is, the wider angle the lens is, and the bigger the number, the more zoomed in the lens is. So, a 16mm lens can capture a very wide field of view, where as a 200mm lens captures a very narrow field of view, it’s that easy, the bigger the number the more ‘zoomed in’ it is.
Lenses are generally categorized into 3 different classes, Wide, Midrange and Telephoto lenses, these names are incredibly descriptive of what they do. Depending on what type of camera that you use and it’s sensor size, the actual number of millimetres a wide, midrange or zoom lens is will be different. To keep things simple as I get started I’m not going to be referring to the focal length of a lens in millimeters but rather the class of lens that they are in and in the next video in this series I’m going to be covering how to determine the right lens for you based on what camera you have and it’s sensor size because it’s a complicated topic, the key thing I will say now though is to know there is a difference between micro 4/3rds, APS-c, and full frame cameras and it’s a very important topic to understand about your camera before you buy a lens for it.
This is a cheat sheet to help show what the numbers are relative to the most common sensor sizes. I use full frame cameras so I will be using them as the point of reference. So, for me a wide angle less than 35mm, a mid-range lens is anywhere from 35-85mm and a telephoto lens more than 85mm. None of this is set in stone though and it comes down to how you use a lens not what I tell you a lens is used for. So, what are differences between Wide, Midrange, and Telephoto lenses and what are they good for?
Wide Angle Lenses
I’ll start off with wide angle lenses. In very general terms, wide angle lenses are what are often associated with that ‘gopro’ camera kind of look, or like a selfie camera on a phone. A wide-angle lens allows the camera to capture a very wide field of view. They are best suited for landscape photography when you want to capture everything you see making your subject very small and having a large focus on the environment, or situations where there is a lot to capture, but not alot of room to do so, like home interiors. This does not mean that is all they are good for, but those are the easiest examples. If you are adventurous you can use wide angles for portraits, but they tend to introduce distortion at the edges of an image, making people look a little wonky. Wide angle lenses also are a little more expensive to make because they require more complex glass inside them to bend the light, so just when you are shopping it’s handy to keep that in mind. A phrase you may hear also is ultrawide lenses, which in really are just the widest of wide angle lenses and eventually you get so wide to a point there is a fisheye effect introduced because of the amount of distortion, they are fun but are very niche types of lenses for unique situations.
Midrange Lenses
Midrange lenses are most common type of lens, they are generally comparable to what you normally see with your eyes. Their image is very neutral and are just the right balance between allowing you to be close enough to your subject that you get nice subject isolation, however not so close it is uncomfortable or intruding. They are pretty much useful for every kind of photography and if a camera is going to have a fixed lens on it, it is almost always a midrange lens. Midrange lenses also introduced very minimum distortion and are the cheapest to manufacture because of their neutral profile meaning that they are a great option when you’re getting started.
Telephoto Lenses
Telephoto lenses are lenses that get you close to a subject, without needing to be physically close to a subject. Using a telephoto lens narrows the photographer’s field of view to just a sliver, so that the photo is really focused on the subject of the image and the background is appears flat and is able to make the background so blurry its non-existent. The application of telephoto lenses can really range, they can be useful for situations where the subject is extremely far away, like wildlife photography or sports, or situations where you want to get close, like macro photography or portraits. However that doesn’t mean that’s all they are good for and a good telephoto lens is often a staple in most landscape photographers kit.
Prime vs Zoom Lenses:
Another quite common term that is associated with lenses is Prime vs Zoom lenses. Thankfully, this is also amazingly easy to explain, prime lenses are stuck at one focal length, like 50mm, and cannot zoom at all, whereas zoom lenses, as the name implies, can zoom. A common range on full frame is 24mm-70mm, this is often referred to as a midrange zoom, because it covers a huge range spanning from a wide angle focal length all the way to a telephoto range and everything in between.
You may be saying to yourself, why then would you ever want a prime lens? What is the benefit? This where it gets fun, for me at least, because prime lenses are fixed at one focal length it is easier to design them to have larger apertures like f1.4 and f1.8. I’ll discuss the importance of aperture in another video, but what it means essentially is they perform better in low light situations, generally you can get sharper images, and can get better subject isolation.
Often a prime lens will outperform a zoom lens at its one focal length. Prime lenses are also usually lighter weight than a similar zoom lens and a little sturdier cause of the reduced number of moving components in them. Lastly prime lenses are a better price because of their simplicity usually, and if you are looking for a value, prime lenses are usually the way to go, though some of the most expensive lenses out there also are good prime lenses, so that’s not always the case.
The catch is what you gain in creative control and quality in your image by using a prime lens, you give up in versatility because of you want to zoom with a prime lens, you will need to use your feet. But say for instance you want to cover the focal lengths 24mm-70mm but only with prime lenses, you will need pretty much 3 different prime lenses to have the same coverage of one zoom lens, and that advantage of a prime lens being light weight quickly disappears because 3 lenses usually weigh more than 1, and if you are at an event or traveling, having to change lenses constantly is not ideal for a fast-paced workflow. For this reason, zoom lenses are extremely practical and convenient if used well.
Zoom lenses are so important because they offer a level of convenience and practicality that prime lenses completely lack. To make things more complicated though, there are two classes of zoom lenses, variable aperture zooms and fixed aperture zooms.
A variable aperture zoom lens is a lens that has a changing aperture as the lens zooms in. Variable aperture lenses are generally more compact lenses and cheaper because manufacturing the lens is a little less complex. Variable aperture zoom lenses can also cover a greater zoom range like 50-300mm because they do not need to use as large glass elements inside them. Variable aperture zooms are great for affordable first lenses that are versatile and also for lenses to travel with as you only need one lens to cover a huge range.
A constant aperture zoom lens is a lens that maintains the same aperture throughout its zoom range. This make the lens have a more consistent performance, typically better image quality, good low light performance across its zoom range and be much more desirable for video work. There are high quality zoom lenses that are both a constant low aperture lenses at f2.8 and cover a range like 24-70, the trade-off is they are bloody expensive and are usually extremely heavy. Constant aperture zooms are better for professional work or those who do not wish to compromise on image quality while using a zoom.
Conclusion:
So, overall, its always going to be a matter of compromise, there is no such thing as a perfect lens, but there are many particularly good ones. The whole reason I started this educational journey was to learns about lenses, and I have a lot of opinions on them, but to put it in very general terms, I prefer using prime lenses when I can, and when you are starting off, I highly recommend you start off learning on a 35mm or 50mm prime lens. Not only are you going to be better able to play around with low aperture photography, which is quite frankly extremely fun, but the limitation of only using one focal length will help you understand composition better and make you a better photographer long term in my opinion.
Shane Bethlehem Photography 