8 Things to Consider Before You Buy Your Next Lens

By: Andrew S. Gibson  

Prime lenses are best for creating portraits like this one, taken with the aperture set to f/1.2 to blur 

the background.

Are you thinking of buying a new lens for your camera? Stop, and read this article first.
One of the hardest things to achieve when buying new camera gear is clarity. Why do you need a new lens, how much should you spend, and where does it fit into the big picture of your gear acquisition? Once you are clear on these points, it makes the process of deciding which lens (or lenses) to buy next much easier.
Let’s look at eight things to consider before you buy that new lens:

1. Budget – how much do you have to spend?

Everybody’s budget is different, and the amount of money you have to spend determines which lenses come into consideration. But, no matter what your budget, hold that figure in mind while you read this article. You may see things in a different light afterward.
My approach is to own as few, good quality lenses as possible. In other words – don’t over buy. Keep the big picture in mind. What lenses would you eventually like to own for your camera? How does your next purchase fit into this plan? Ideally, you should have a good idea of which lenses you need, and then you can plan accordingly.
This type of thinking can lead to a big shift in what lenses you decide to buy. For example, a few years ago I became frustrated with the size and weight of my Canon system. I was also thinking ahead to some travel plans I had coming up, and realized it was important to keep my kit as lightweight as possible (hand luggage allowances are very low and strictly enforced in New Zealand airports). That led to the decision to switch to the Fujifilm X-Series system. I now have the lightweight kit required for traveling.

2. APS-C or Full-frame?

Most manufacturers offer both APS-C and full-frame cameras in their ranges. But this makes buying lenses even more confusing.
Let’s say you own an APS-C camera. But at the back of your mind you think you might one day buy a full-frame body. That raises the question – do you buy a lens that works on APS-C bodies only (the advantage being that it is probably smaller and lighter than a lens that would fit a full-frame camera) or one that fits a full-frame body as well (which will probably be larger and more expensive)?
Tricky question to answer, isn’t it? And that’s not even taking into account the difference that sensor makes to the lens’s angle of view.
Ideally, you should decide when you buy your first camera body whether it should be APS-C or full-frame, then stick to the same sensor size in the future. It greatly simplifies the lens buying process, and eliminates a lot of confusion.

What do these two lenses have in common? They are both 35mm f/1.4 lenses. The Canon one (left) is much bigger than the Fujifilm lens (right) because it is made to fit a full-frame camera. This is a good example of how sensor size, affects lens size.

3. Don’t fall into the focal length trap

The focal length trap is the belief that you need zoom lenses that cover every conceivable focal length. For example, if you start off with an 18-55mm kit lens, then buy a telephoto zoom, you might feel that you need one that starts from 55mm so that you don’t miss out on any focal lengths in between.
This simply is not true. The next point explains the way you should be thinking about lenses.

4. What subjects are you going to photograph?

Continuing with the 18-55mm kit lens example, you may find yourself considering the following second lenses: a 50mm prime as a portrait lens (giving you the benefit of high quality imaging and wide apertures), or a macro lens for taking close-up photos of insects and flowers, or wide-angle zoom for landscape photography, or a super-telephoto for wildlife and sports photography.
The key point here is that lens choice is related to subject. The subject always comes first. Once you know what you are going to photograph, you can choose the best lens (or lenses) for the job. Focal length is a secondary consideration.
In other words, don’t buy a lens because you think you should own it, buy it because you actually need it.

5. Should you buy a zoom or a prime lens?

The benefit of zoom lenses is convenience. If you are a wedding photographer it is much easier to zoom from a wide-angle to a telephoto when you need to, than it is to change lenses. If you are a landscape photographer it is easier to use a wide-angle zoom to frame the scene precisely, than it is to change prime lenses (or it may not be possible to stand where you need to get the shot).
The benefits of prime lenses are image quality and wider apertures. Compare an 18-55mm kit lens (typical maximum aperture f/5.6) with a 50mm prime with maximum aperture of f/1.4. There’s a four stop difference 16 times more light) between f/1.4 and f5.6, which helps you take photos with blurred backgrounds, and also to shoot in low light conditions, without raising the ISO too much. That’s why a 50mm prime is a better portrait lens than the 18-55mm kit lens (taking us back to the point about lens choice being driven by subject, not focal length).
Some photographers prefer primes, others zooms – thinking about your priorities will help you decide which is best for you.
For example, if you are a landscape photographer who always shoots at f/8, f/11, or f/16 then the wider apertures that prime lenses have are of little use to you, and a zoom may be a better choice.

Action photos require a telephoto lens and a camera with a good autofocus system capable of tracking moving subjects. A zoom will help you frame the subject accurately.

6. Don’t forget about weight and size

Think about the weight and size of your lenses carefully. After all, you are the one who is going to be carrying them around.
But there is another thing you should also think about when it comes to size, and that is filters. You can save a lot of money on filters by buying smaller lenses. If you’re curious to see how much, do a search for circular polarizing filters and compare the prices of the same filter in 58mm and 77mm sizes. If you need to buy a lot of filters (landscape photographers take note) then you can potentially save hundreds of dollars by buying a smaller (the diameter of the lens or filter size is also smaller) lens.

Wide-angle zooms are ideal for landscape photos and will help you take photos like this. Bear in 

mind that smaller lenses also require smaller (and less expensive) filters.

7. Build quality, weather proofing and autofocus

Most manufacturers have inexpensive, middle range, and expensive or high end lenses. Inexpensive lenses may seem like a bargain at the time, but they won’t be built as well as more expensive ones, and they may also have inferior (i.e. slower and noisier) autofocus motors.
At the other end of the scale expensive lenses tend to be built well, use good quality autofocus lenses (i.e. faster and quicker) and may also be weatherproofed (important if you take photos in bad weather or dusty conditions).
Bear these points in mind when considering a lens. Don’t forget to ask how well the lens is built, whether it is weatherproofed, and the speed and quality of the autofocus motor.

Wide-angle lenses are also helpful for taking photos indoors, where you may not have space to 

move back to use a longer focal length.

8. Brand name or third party?

You can often save money by buying a third-party lens for your camera, but in my opinion it is best to buy a lens made by your camera’s manufacturer whenever possible. Unless you have a specific reason to buy a third-party lens (usually because the type of lens you need isn’t made by your camera’s manufacturer) then stick with OEM (Original Equipment Manufacturer) lenses. They hold their value better, and autofocus performance is usually superior.
Editor’s note: for a good discussion on that topic, head to: Brand Name Versus Third-Party Photography Gear: Which is better?

If street and candid photography is your thing, then consider buying smaller lenses to help you take photos like this, without being noticed.

9. Image Stabilization*

An Image Stabilizer is a motor inside the lens, that moves the elements in a way that compensates for the movement created by camera shake. It is given different names by different manufacturers (Nikon, for example, calls it Vibration Reduction). It helps you take photos in low light, using lower ISO settings or smaller apertures, than would otherwise be possible. Lenses with Image Stabilization cost more than their non-stabilized counterparts, so think carefully about whether or not you need it, before paying the extra money.
* Some manufacturers, like Sony and Pentax, build Image Stabilization into the camera body, not the lenses.
Hopefully these points will help you decide which lens to buy next for your camera. If you have any questions about lenses let us know in the comments and I will do my best to answer.

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Mastering Lenses
If you want to know more about buying and using lenses then please check out my ebook Mastering Lenses: A Photographer’s Guide to Creating Beautiful Photos With Any Lens.