Whether you shoot on Canon, Nikon or Sony, or use solely third party gear, this post is designed to give you the best available information, to help you in your lens buying future. To make sure you know what you’re doing when it comes time to replace that old kit lens, I’m gonna walk you through focal length, aperture and what all those little letters on your lens mean.
Step 1 – Focal Length
I’ve written about this in great detail in the past in this post, and I very strongly suggest that you read it, but for the basis of choosing the right lens, the higher the focal length (number before ‘mm’), the more zoomed the lens is going to be. Of course, it’s a little bit more complicated than this, but more information can be found in the post mentioned previously.
Different focal lengths have different uses for different situations, but it’s all about choosing the right lens for you. Ask yourself what lens you currently use the most and what you like to take photos of, and that will give you a good idea of what sort of lens you want. Here’s a list of focal length ranges listed below, taken from my post on focal length.
Ultra Wide Angle 14-24mm
These lenses are often considered specialty items and the range is not often included as part of a kit lens. They create such a wide angle of view that they can look distorted as our eyes aren’t used to seeing that sort of range. They’re often used in event and architectural photography for getting a lot into a photo when shooting in a confined space. Wide and ultra wide lenses are about putting yourself in the middle of it all, not just about getting the whole of a scene in. These lenses are not particularly suitable for portraits as they enhance the perspective so much that the facial features can look unnatural.
Wide Angle 24-35mm
This is where you’ll find most kit lenses for full frame cameras will start at. 24mm is roughly the point at which the distortion that appears to stretch the side of the image stops appearing unnatural. They are used widely by photojournalists for documenting situations as they are wide enough to include a lot of the context and still look realistic.
It’s in this range at about 45-50mm that the lens will reproduce what our eyes will see (excluding peripheral vision). I personally like to use this range when shooting on the street or in situations with friends in a close setting such as at a dinner table or the pub. A standard lens such as a 50mm f1.8 is an excellent, inexpensive addition for a camera and will provide excellent results. Prime lenses (lenses with a fixed focal length – can’t zoom) will always provide better results than your kit lens as the lens is built with a single purpose in mind. It does one job well rather than multiple jobs poorly.
Mild Telephoto 70-105mm
This range is often where kit lenses will stop and you’ll start to get into the range of telephoto lenses and portrait primes (around 85mm). This is a good range for portrait lenses as the natural perspective of the lens will separate the face from the background without completely isolating the face.
Lenses in this range are often used for distant scenes such as buildings or mountains. They’re not suitable for landscapes because of the way they will flatten the perspective of a scene. Lenses higher than this range are mostly used for sport and animal photography.
These lengths vary depending on what type of camera you’re using, and it’s worth noting that the majority of camera users are using a crop sensor camera, meaning that the size of the sensor is smaller and that, in turn, crops the image. What this effectively means is that a photo you’ve taken on a crop sensor at 50mm, is going to look more like 75mm – more zoomed.
Kit lenses typically range around 18-55mm on a crop sensor lens and these lenses won’t fit on a full frame camera. If you’re looking to upgrade to professional quality gear, you’ll still want to find a focal length as close to that as you can, because if you step your lens up to 24mm, you’re going to be losing a lot of the wider angles. If it’s unlikely that you’re going to be upgrading to a full frame, professional camera in the near future, I would strongly suggest that you upgrade to a better quality crop sensor lens.
Step 2 – The Right Aperture
Aperture can be a confusing thing when it comes down to buying a lens, and as usual, I have an in depth article telling you everything you need to know, that can be found by clicking on that link. The lower the number (f/1.4, f/2), the wider the aperture will be and the more light the lens will allow in. When buying a lens, you should try to get this number as low as you can afford to go, without sacrificing the focal length that you want.
The lens that I use the most is my 24-70mm f/2.8 as it allows me a good zoom range and a very wide maximum aperture, which allows me to let loads of light into the lens and achieve a shallow depth of field. My lens is an f/2.8 and that means that no matter where I’m focusing, I can still set my aperture to f/2.8, which isn’t something that you can do with every lens.
A typical Canon kit lens will have the marking f/3.5-5.6, which means that the maximum aperture will change throughout the zoom range. The lens will stop at f/3.5 at 18mm, narrow to f/4 at 24mm, then f/5 at 39mm and finally f/5.6 at 47mm. These stops allow progressively less light into the lens into the lens, with a total difference of 1 1/3 stops, meaning that f/5.6 allows less than half the amount of light into the lens as f/3.5 does.
As you can see, this will really hold you back when shooting in low light, so I thoroughly recommend that the first upgrade you look for when looking for a new lens is one what allows you to have a wider maximum aperture that doesn’t change throughout the focal length.
Step 3 – What do all Those Letters Mean?
Well, they’re acronyms, and they vary between cameras, but they all essentially mean the same thing. Here’s a little diagram below that demonstrates that these letter mean by brand. With the exception of the crop sensor marking, every time you get some extra letters, your lens is getting more expensive and better quality.
For those that don’t understand what the terms above mean, here’s some definitions for you, along with a couple extra that aren’t listed.
Manual focus only. This is typically only found on either very cheap lenses, or much older lenses, and the acronym is the same throughout brands.
This is the version of the lens that you’re using. Lenses that have been around for a long time and have become very popular, aren’t usually replaced completely, the lens designer will take the lens and find ways to improve it and release it again under the marking of II – version 2. The higher the number, the better the lens.
These lenses will still fit crop sensor cameras, but you’ll end up with the crop factor that I mentioned in step 1. These lenses are specifically designed for full frame cameras and project a larger image onto the larger sensor, inside the full frame camera.
These markings tell you that they’re built for a smaller camera, with a smaller sensor and you’ll find that the focal length has also been adjusted accordingly. It also means that the projection from the lens is much smaller and will not work on a full frame camera; if you were to put it on a full frame camera, it would produce very heavy vignetting.
We all know what this is, it’s a way of stabilising the camera or lens so that you’re able to take a photo at a slower shutter speed. Different cameras have different techniques and locations for this, but they all essentially do the same thing.
Silent Wave Motor
This is a much faster focus motor, with clear advantages, but it’s also fairly silent and the end of the lens doesn’t tend to move when focusing. This has the added advantage of being able to put a filter on the end of your camera and not having to worry about it rotating as you focus.
Most lens manufacturer produce lenses to a price, so your kit lens isn’t usually very good quality, and this is especially true with my experience from Canon kit lenses. Stepping up to pro lenses, you’ll find a difference in quality and usually a wider maximum aperture, which is very useful for low light situations.
Low Dispersion Glass
This is used to reduce nasty chromatic aberration that is produced by cheap glass. You’ve probably seen it before, but may not have known what exactly it was called, but here’s an exaggerated example of it – notice the blue on the face:
A Note to Finish On
If you’re looking to improve the physical quality of your images, the best way to do this is to replace your kit lens (or don’t buy one to begin with) as soon as possible. Prime lenses are always going to provide better quality images for cheaper, and are excellent low cost alternatives to kit lenses.
Buy the best lens that you can afford for the focal length range that you use the most, and you won’t have too many complaints. Don’t worry if you’re using a crop sensor camera and you’re buying a full frame lens, just work with what you got. If you’re a good photographer, these obstacles won’t be a hurdle in taking great photos.