I get many questions on choosing one lens, so I decided to share some of my ideas on the subject.
Why use only one lens?
The idea is to limit our options. If we only have one lens we can focus our creative energy into reading light, composition and less on gear selection. The more time we spend with a single lens, the more we learn about that lens, its strengths and weaknesses. All lenses, even the most expensive ones, have their flaws. And even the cheapest lenses have a sweet spot, a combination of focus distance and aperture where they really shine. Our goal is to know our lens's strength and to use them to our advantage while avoiding their flaws when possible (Or learning to exploit their flaws in a creative way).
Once we spend some time with a lens we will begin to see like it, without looking through the camera. This makes photography more intuitive and efficient. I can come upon a scene and know whether or not I can compose an image, again, without even pulling the camera out of its bag.
Using one lens also teaches us some life lessons, like learning to let go. Most scenes don't make great photographs. We need to learn to put the camera away and just enjoy what is happening around us. Just because we can't make a photograph doesn't lessen the importance or significance of a moment or event. We should appreciate every moment, camera or not.
Prime Lens or Zoom?
A prime lens is the most restrictive but also yields the most rewards. A lens that is close to our eyesight, somewhere between 40-50mm is ideal. If you like to get close, like I do, then a lens that has close focusing abilities is nice. The prime lens I use is a 50mm macro lens. Though if you tend to prefer wider compositions then a 35mm works nicely and is still an angle we can learn to see without looking through the camera. I wouldn't go much longer with a prime, but some people use a 70mm. Prime lenses are the easiest to learn about. With only a few sessions we can recognize when the lens performs at its best and if there are any combinations (aperture-focus distance) where it doesn't perform up to our standards. Certain lighting situations can, like direct light, reveal flaws or pleasant surprises from our lens. It really doesn't take long to get used to one focal length. And before you know it, you won't even think about it or wish you had more options, you will just accept what you have and work with it.
Zoom lenses are easier to digest when it comes to choosing one lens. However, it is much more difficult to discover their sweet spots and take advantage of the single lens approach. A zoom lens might perform beautifully at 38mm at f8 when focused at infinity but at 58mm, it might be soft and then at 70mm, be sharp again! Center sharpness and edge sharpness change throughout the zoom range, even with the highest quality lenses. I think compositions are often weaker when we use a zoom, we tend to get lazy and are less creative. If you just can't wrap your mind around a single prime lens then stick with a zoom with the least amount of range. The "standard" zoom, like the 24-70mm is your best bet. I would recommend spending time at each of the primary positions like 70mm, 50mm, 35mm. Maybe say to yourself that you will only photograph at 70mm one week, then 35mm another. This will make it easier to learn your lens's characteristics. .
Obviously, this approach isn't appropriate for all styles of photography. A 35mm prime isn't really going to work if you are primarily a wildlife photographer. That doesn't mean you can't use a minimalist approach. Working with minimal gear and understanding every aspect of that gear will benefit us no matter what type of photography we enjoy. I enjoy spending time in the presence of wild animals. On occasion, I will rent a telephoto and spend the day looking for animals. I give myself plenty of time to learn the lens's characteristics so I can use it at its best. I rent the same lens every time so I am familiar with its operation, however, every lens is different, even two lenses of the same model can have some unique variations and the internet is loaded with reports of "bad" copies of lenses. So always give yourself some time with a rented lens before committing to serious work. In my studio, I have a dedicated lens just for extreme macro work. This type of photography is impossible in the field and requires a very precise approach, special lighting, in a very controlled environment.
We all get stuck in our head the idea that we will miss something if we don't have every possible option available. That has been placed into our minds by clever marketing. Once you spend some time with one lens, you will forget about it. One lens is all you have and all you really need. That is the final goal, to forget about our gear. The mechanics of photography must be mastered and then forgotten if we hope to create meaningful photographs and learn about our world and ourselves in the process. Cameras, lenses, computers and printers are just tools, they don't make great photographs, you do. You just need to cleanse your mind of all the gear and gimmicks so you can start seeing.
Use a lens you already own. Please don't go buying an expensive new lens. If want to try a lens, rent it first. Then if you like it, buy it used. Don't get sucked into the upgrade circle.
If you have any questions or comments please feel free to contact me.