This text is definitely aimed at beginner photographers. Most of us, when purchasing our first camera, opt for a kit that includes a lens. Typically, this is a universal model with average specifications, which meets basic needs.
Such a lens usually has two rings. The larger one is called the zoom – it allows for bringing objects closer and farther away. The smaller one, located closer to the camera body, is responsible for setting the aperture. It usually remains in the position of maximum opening, and the aperture value is automatically adjusted by the camera or manually by the user.
Lenses of this type are called "kit lenses".
Both dials enable the adjustment of the lens's operation. The zoom changes the position of the lenses relative to each other and their distance from the sensor or film. This allows for zooming in or out of the object, which means that the same lens can be successfully used both in a tight space and in an open area, such as a park. Thanks to this, we don't have to physically move closer or further away from the photographed object - we can conveniently zoom in and out by turning the ring. Standing next to a person, we can zoom in on their face and take a portrait or zoom out to take a photo of their full figure. Sounds ideal? Unfortunately, this convenience comes with significant compromises.
The mechanical complexity of such lenses causes a number of problems. First of all, the lens array is much more complicated, which often leads to various issues in budget designs, such as chromatic aberration or even the inability to achieve perfect sharpness in photos. Another significant problem can be the image geometry representation – some lenses are sharp only at the center of the frame, while the edges remain blurry, or they generate spherical distortions. We quickly discover that some lenses are much more expensive than others, even though they have similar specifications on paper. However, there is one parameter by which the price of a lens can be easily estimated – the aperture value.
In my experience, lenses with a low aperture value are usually more expensive. This is due to the need for more precise mechanisms, better materials, and generally more refined construction. A low aperture value allows more light to enter, which translates to potentially better photo quality, greater capabilities in low light conditions, and attractive effects such as beautiful bokeh.
However, it may turn out that at reasonable ISO values, the lens struggles in poorly lit rooms, resulting in blurry photos, or, for example, our portraits appear flat, with the face not standing out from the background, and unlike those taken by professionals. This is a trap that can lead to frustration and discouragement, and consequently to abandoning the photographic passion when it turns out that the equipment does not meet our expectations.
So, is the aperture to blame? I suspect that manufacturers could mechanically unlock the aperture blades to open wider – that is, to reduce its value. However, this would cause the lens to no longer meet certain standards. You might not know it yet, but the higher the aperture value (meaning a smaller opening created by its blades), the sharper the photo. This is precisely why some lens flaws can be hidden by increasing the aperture value.
The earliest lenses were fixed focal length and featured a simple optical design, typically consisting of 2-4 lenses. Their uncomplicated construction and lack of moving parts allowed for easier production at satisfactory quality. This enabled the use of apertures with lower values. It's worth noting that the first photographs were taken on materials with significantly lower sensitivity to light, which required very long exposure times and a large amount of light. For this reason, the oldest lenses did not have apertures, and their brightness corresponded to values below f/1. This allowed for shorter exposure times and gave old photos their unique shallow depth of field.
Today, fixed focal length lenses primarily serve specialized functions. They can be divided into several main categories:
Wide-angle / fisheye
Standard / portrait
Telephoto
This division can be further detailed, but even at this level, clear specializations are evident.
Wide-angle lenses, including fisheye, are mainly used in interior and landscape photography, as well as during events when capturing the widest field of view is desirable. They are characterized by significant image curvature, which is particularly noticeable at the edges of the frame.
Standard lenses roughly correspond to the field of view of the human eye. On the other hand, portrait lenses, with their slightly longer focal length, gently bring the image closer, which often positively affects facial geometry. The choice of the right lens for portraits is a matter of individual preference—there are as many opinions as there are photographers.
Telephoto lenses are distinguished by their high magnification and are used in wildlife, sports, and macro photography. However, it should be noted that in professional wildlife and sports photography, zoom telephoto lenses with complex construction and high precision are most commonly used. Such constructions are extremely expensive, creating a clear boundary between amateur and professional equipment, and the price differences can be enormous.
If you're asking yourself this question, chances are you don't yet have a well-developed set of lenses and want to avoid mistakes when shopping. If you can't afford a lens worth one or several average national salaries, you must be aware that cheaper alternatives may quickly reveal their limitations.
If you photograph in good lighting conditions, there is a good chance that even a cheap zoom lens will meet your expectations. Simply stop down the aperture a bit, and many problems arising from lower optical quality will just disappear. However, if you're interested in portraits, seriously consider purchasing a prime lens. My favorite portrait lenses don't even have autofocus – and they work great. That's how it works.
The choice of lens largely depends on your needs. There are areas of photography where a prime lens won't do – anywhere that requires dynamic action: sports, weddings, events, or reportage. In such situations, speed and discretion matter, and the ability to change the focal length becomes invaluable. In good lighting conditions, you can still rely on cheaper equipment, but when the light starts to fade, you'll quickly feel the limitations – you'll be forced to raise the ISO, which means more noise, and this translates to a decrease in image quality.
Simple rule: if your work with the camera is quite static, you can save money by buying a prime lens with the appropriate parameters. At most, you'll do a bit of walking – but in return, you'll get better image quality. If your work with the camera requires movement – you most likely need a zoom lens, or several...
If you photograph nature as a hobby on sunny days, a 70-300 mm zoom lens with a stopped-down aperture should provide you with adequate comfort.
On the other hand, in dynamic lighting conditions and dynamic environmental conditions, you will most likely need an expensive zoom lens. Which one specifically? That depends on what you want to do.
Please treat this text as an introduction to serious considerations – you don't have to agree with it. In the final paragraphs, I will try to provide more specific answers. I'm writing this as someone who uses equipment daily and rarely reads buying guides or industry magazines. However, I've made so many mistakes in my life that I'm starting to believe I have something to say on this matter.