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How to Buy a Camera Lens - Part 1 - Focal Lengths

Lenses come in all shapes and sizes and there are literally hundreds out there on the market. Deciding between them can be a daunting task, even for seasoned professionals and to beginner hobbyists a significant financial investment.

There are many articles out there on the web which will go into the intricate details of each individual product. This article is written for the amateur hobbyist and the beginner photographer. In this article and in the following articles, I aim to break down the absolute basics that will help you make the decision that is right for you and your budget when it comes to buying gear, taking pictures and editing your work, which could hopefully save you $$$ in the long run.

What will we cover in this lesson:

• Brands

• Focal lengths (mm ranges)

• Prime lenses


I want to get this section out of the way first, as in my opinion this is the easiest of all to cover. First and foremost, there is VERY little overall difference between lens brands at the amateur hobbyist level. Nikon may make a great 70-100mm and Sigma may make a very good 10-20mm, but if you go with any of the major brands, you should be ok.

The biggest lens and camera manufacturers on the market today are listed below. Each of these companies will make lenses exclusively for their own cameras. So Canon lenses for example wont fit on Nikon body.

Nikon - Website Link

Canon - Website Link

Samsung - Website Link

Panasonic - Websie Link

Pentax - Website Link

There are also a number of third party lens manufacturers. These companies will make each lens with a number of different mounts. So make sure if you buy a lens from them that you are buying the Nikon version if you have a Nikon camera etc.

Zeiss - Website Link

Sigma - Website Link

Tamron - Website Link

Some would argue and I would generally agree, that when it comes to third party lenses that the overall value for money is better.

For Example

The Canon, according to the reviews is marginally better, but you will be paying $600 more than the sigma for that benefit. Most amateur photographers probably wouldn't be able to see the difference between them. Just remember, when you look into your next purchase, that there are often VERY good alternatives to be found in 3rd party lens manufacturers.

Focal lengths (mm range):

Ok, so on to the serious stuff! If you have a look at the nearest lens you have to hand, or at any of the pictures in this article, you will see that somewhere written on it a number in mm. It is usually written on the front of the lens, and then again around the rubber zoom ring on the lens barrel. This number, or range of numbers is the focal length, or focal range of the lens. In practice, the larger the number of "mm" the more "zoom" the lens has.

The lens in the image below for example has a focal range of 18mm to 55mm.

This is a very common range, and is often the sort of focal range that comes packaged with cameras straight out of the box.

Below is an excellent set of images that demonstrates how different focal lengths would look, if you stood in the same spot and slowly "zoomed in" from 18mm to 300mm on the same scene.

Image from NIKON USA

Most lenses, and likely the lens which came with your camera, will have a variable focal range, for example something like "17mm - 50mm". This means that by adjusting your lens, you can achieve any focal length between the two values. From the photographers point of view, it is the same as "zooming in" on your lens. Lenses come in all different focal ranges...

From very narrow....

To very long....

Different types of photography will usually require different focal ranges. Below is a very rough breakdown:

Wide Angle 10mm to 28mmLenses: 10m

Common in landscapes and interiors/ architecture, as the wide angle allows the photographer to capture a whole room, building or to capture a wide open landscape.

Normal Lenses: 28-40mm. Commonly used in travel photography, great for taking pictures of people, and this focal range is similar to what the human eye can see.

Short Telephoto Lenses: 40-60mm. Commonly used for portraits and event photograph, allowing the photographer to stay at a reasonable distance from the subject, and capture either full body shots, or close portraits.

Telephoto Lenses: 60mm to 300mm

Commonly used for wildlife and sports photography, as it allows the photographer to take pictures of animals and people from a long way away.

So next time you are looking at some shiny new lenses in the store, have a think about the type of photography you will be using it for. There is not much point in buying a 10mm - 20mm lens, if you really want to take pictures of wild birds for example.

Prime Lenses:

So what about lenses that only have one focal fixed focal length?

Every now and again you may come across lenses such as:

Lenses with a fixed focal length are commonly called "Primes". Due to them being fixed, you are unable to zoom in or out, If you want to do so, you would need to physically move closer to the subject.

"So why would I want a Prime if I can just buy an 18mm - 200mm?" I hear you ask.

As you can imagine, a massive lens like this:

Is hardly practical to carry around with you every day, or whilst on holiday. And wilst yes, that particualr example is a bit of an exaggeration. Prime lenses are usually much smaller, lighter and more discrete than larger zoom lenses.

On my trip to Vietnam, I almost exclusively used my 35mm prime, for shots like this. As the lens was small, it was easy to carry around with me and gave me excellent results due to its sharpness and image quality.

Due to primes being much simpler to make, as they have far less glass components and moving bits, they will generally produce the best quality and sharpest image possible.

A good rule of thumb is that the longer the focal range (difference between biggest and smallest number), the poorer the overall final image it will produce. This is because in order to make a lens this diverse, it needs MANY more glass and moving components.

A longer focal range however, is of course far more versatile, and will allow you to carry less lenses, meaning they are much more practical when on holiday or travelling for example.

So when picking out a lens, we always need to weigh up this trade of between quality and versatility.

The final hard and fast rule, is that the more a lens costs, the better the overall image. End of story. . Th lenses that come with camera bodies or "Kit lenses" will sadly never be as good as a top of the line product.

Check back in for part two where I will go over aperture ranges, and part 3, where I will break down all the acronyms and Jargon you see in those super long names.

All my articles are written for the benefit of beginner and amateur photographers. If you have just started out, perhaps as your new years resolution and would like to receive all these juicy tips and guides directly to your inbox, please sign up to the mailing list below.


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