How to Read Camera Lenses – It’s Easier than You Think

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Starting out in photography is tough enough as it is – and that’s without trying to learn how to read camera lenses.

Photography can be expensive and there’s a steep learning curve involved.

Any tricks or tips that can make this process easier will go a long way to keep you interested, improving and passionate.

There’s so much to focus on – which might force you to delay learning how to read your lens the right way.

I won’t blame you for thinking it’s difficult, or for not wanting to learn it right now – but the rewards make it worthwhile.

Learning how to read a lens will give you better control over your lens and ultimately – your photography.

There were a couple of times while I was learning that I wanted to throw the towel in and go back to using my smartphone (though their tiny sensors pale in comparison to a dedicated camera).

It’ll take a Little Time to Get Right

Learning how to read camera lenses isn’t easy when you’re getting started – there’s so much else that needs your attention.

In hindsight, all I needed was some simple guidance. It helped me break through the confusing early stages and got me started down the right path.

There are little tips and tricks you can use to make the whole process easier – and tons of visualizations and mnemonics you can use to remember the trickier things.

You’ll find the information you need now, laid out here in a simple to understand way to help you learn how to read camera lenses – without all the added frustration.

Different types of lenses and different brands might mark their lenses in different ways, so I’ve done my best to cover the major ones for you.

Before getting started though, get yourself a good lens diagram that clearly shows all the markings on the lens.

Try the ones that show the front and side view if possible.

Using this along with your actual lens will help you get familiar with everything you’ll learn today.

This whole process isn’t going to take too long, but it needs consistent attention. Setting a little time aside every day will make this all a lot quicker.

With all this in mind, let’s get into the guide!

Camera Lenses Explained for Dummies

I’ve already put up guides that go into more detail on how camera lenses work and what’s inside them.

I’ll just give you a brief overview here to set the scene.

The camera is totally useless without a lens. It can’t gather all the scattering light and redirect it onto its imaging sensor – this is why you need a lens.

It’s ingeniously designed and engineered to use complex physics to harness and redirect the light that comes into the lens, onto the camera sensor.

Several pieces of expertly shaped glass inside the lens is moved and adjusted to get the light perfectly focused onto the camera sensor – and in turn – giving you perfectly focused and sharp images.

Camera lenses are marvels of technological and scientific progression and there’s no doubting it. The people who design them are some pretty intelligent folks.

The issue is that this feat of engineering and tech can be a terribly complicated topic for the average Joe to tackle.

Luckily though, I’ve already spent hours, even days, trying to break down this information into something I can understand – and eventually teach.

It suffices to know that lenses capture as much scattering light it can through its aperture opening and redirects it onto the camera’s imaging sensor – producing a clear and tact image for the world to see.

There isn’t too much use going into more detail on this, for now, so let’s move on to learning to read camera lenses the right way.

Camera Lens Numbers Explained

This section is going into all the numbers and figures you’ll find on your lens.

We’ll go through it by topic (aperture, focusing, zoom, etc.) so that you know exactly how each reading affects your photography.

Bear in mind that different lens brands mark their lenses in quite a number of ways.

This is why I said it’s a good idea to get a lens diagram (even better if it a diagram of your exact lens) to help you better visualize and make notes on what you need to understand.

Let’s move on to the first set of numbers.

Aperture

This is a little more complex than shutter speed and ISO, so we’ll deal with it now and get it out the way first.

Aperture refers to the circular opening that controls how much light is let into the lens.

Aperture is written as a fraction of the total focal length of the lens.

How is Aperture Written?

For example, you’ll see it written as f/2.0. This means that the aperture is half the size of the focal length (in millimeters).

If your focal length is 50mm, your aperture – at f/2.0 – will be 50/2 = 25mm.

Aperture is measured in f-stops and each stop allows double the amount of light in than the previous stop.

So an f/2.0 aperture will allow twice as much light in as an f/2.8 aperture.

The area of the opening is what we consider, not the diameter of the opening.

You can also get half-stops and third-stops on some cameras. This gives you more precise control over the aperture and how much light you want to let in.

Wider apertures are represented by lower numbers (f/1.4) and narrow apertures are represented by higher numbers (f/16).

When buying a lens, the most important number is the maximum aperture value – this decides how ‘bright’ the lens is and its speed.

Aperture Stops

These are the “levels” of aperture opening – you can also find some lens apertures between these full stops, e.g. an f/1.8 lens is the third stop between f/1.4 and f/2.0.

The aperture stops are:

f/1.4 – f/2.0 – f/2.8 – f/4.0 – f/5.6 – f/8.0 – f/11 – f/16 – f/22 – f/32

Remember that f/1.4 is the widest aperture here, and f/32 is the narrowest.

When reading from the left, each of these stops allows in twice as much light as the previous stop.

Between each of these stops, there are half and third stops too.

Focal Length and the Types of Camera Lenses

The focal length of a lens is the distance between the imaging sensor and the point where the light converges in a lens (its point of best focus).

Some lenses have the ability to zoom in and out (they’re called zoom lenses) and they are said to have variable focal lengths.

This is achieved by some ingenious feats of engineering and physics, way beyond the scope of this article.

Lenses that can zoom in or out are called prime lenses – because the non-zoom lens wasn’t a catchy name.

Here’s a quick list of the types of camera lenses you’ll get at the different focal lengths:

Ultra wide-angle and wide-angle lenses: 8-35mm
Standard lenses: 50mm
Telephoto lenses: over 70mm into the 1000s
Fisheye lenses: 4mm and 8mm
All-in-one zoom lenses can zoom between any or all of these ranges
Portrait lenses: 50mm and 85mm

How is Focal Length Written?

All focal lengths are written in millimeters and are separated into wide-angle, standard, telephoto and all-in-one zoom lenses.

You’ll see focal length written as follows:

For zoom lenses, you’ll see two numbers written like this: 18-55mm
For prime lenses, you’ll see one number like this: 50mm or 85mm

Wide-angle and ultra-wide angle lenses have a shorter focal length and range from 8-35mm.

Standard lenses are prime lenses with a 50mm focal length – it’s called 50mm because the level of zoom and perspective is very similar to what our eyes see.

Telephoto lenses start from around 75mm and up.

So as an example – what does 55-200mm lens mean?

It’s a zoom lens that has a variable focal length ranging from 55mm up to 200mm.

Remember that the real world focal length will be influenced and changed depending on whether the camera has a full-frame sensor or not.

Types of Lens Focusing

There are three types of focusing on most cameras:

Automatic focus (AF)
Manual focus (MF)
Some cameras also have a hybrid mix of both of these – an assisted focus

There’s often a quick toggle switch that’s marked “AF/MF” on your lens that lets you change between the two modes.

Be sure to only manually adjust your lens when you’re on the “MF” setting as not all cameras allow for manual adjustments while in “AF” mode – you can actually damage your camera.

Lens Diameter for Filters and Attachments

Lens diameter is a number you’ll find near the front of your lens.

It refers to the size (in mm) of the threads for attaching all kinds of filters and UV attachments.

The “ø” sign is used along with a number (the mm measurement).

If you want to attach and filters or anything, it’ll need to match this size – otherwise, you’ll need an adapter.

If you can’t find the lens diameter measurement number on the front of your lens, it’ll usually be on the side, somewhere near the front of the lens.

Brand-Specific Markings

This is probably the most diverse area when you’re learning how to read camera lenses.

The same feature can be written in a bunch of different ways, depending on which brand you go with – and there a lot of lenses out there!

In this section, you’ll see the different ways lenses are marked on the most popular lens brands – let’s get into it.

You’ll have Sony, Sigma, Canon, and Nikon lens numbers explained in an easy-to-compare way.

Full-Frame Sensor Lenses

Full-frame lenses have a larger sensor size that lets them capture a bigger frame.

They’re generally more expensive – but you actually get the full-frame experience and don’t have to worry about cropping and zooming.

Different brands use the following ways to show their lens is full-frame compatible:

Canon: EF
Nikon: FX
Sony: FE (for their mirrorless models)
Sigma: DG

These are the most common lens brands, so we’ll stick with these four throughout this section.

Cropped Sensor Lenses

These lenses have a smaller sensor size than the full-frame sensors.

This means that you’re getting any images you take will be cropped.

The exact crop factor will depend on the lens brand, but it’s usually around 1.5x.

So a 50mm lens will give you the real-world focal length of 75mm – your 50mm will basically be transformed into a 75mm lens.

The major brands mark their cropped lenses in the following formats:

Canon: EF-S
Nikon: DX
Sony: E (again, for their mirrorless models)
Sigma: DC

P.S. You might often see the sensor category referred to as the format of the lens.

Image Stabilization

Image stabilization is how lenses and cameras work together to reduce the effects of handshakes and bumps on image quality.

They use clever techniques to help your

This is often done in both the lens and the camera body – and again, it’ll depend on exactly what camera and lens you use.

Keep an eye out for these markings (the full name is written in parentheses):

Canon: IS (Image Stabilization)
Nikon: VR and VR II (Vibration Reduction – VR II is the second generation of this technology)
Sony: OSS (Optical Image Stabilization)
Sigma: OS (Optical Stabilization)

Image stabilization is important if you want to get more consistently sharp photos from your lens.

Autofocusing Motors

The ultrasonic motors let your lenses focus quieter and faster than ever before.

There are some differences between brands in the performance of these – but they all do the same thing.

You’ll find them written in these ways:

Canon: USM (Ultra-Sonic Motor)
Nikon: SWM (Silent Wave Motor)
Sony: SSM (Super-Sonic Motor)
Sigma: HSM (Hyper-Sonic Motor)

Low Dispersion

This refers to lenses that have been carefully designed and manufactured to reduce chromatic aberrations.

This usually happens around the edges of your photos and at the edges of objects (especially rounded ones) where light isn’t refracted accurately.

The special design helps fight this effect and gives you more color-accurate photos – usually only professionals will notice the difference.

This is how low dispersion is marked:

Canon: ED
Nikon: ED
Sony: ED
Sigma: APO

Final Thoughts

That’s it for our “How to read camera lenses” guide.

By now, you should feel prepared and confident to handle reading the most common lenses out there.

You’ve learned how most lens characteristics are marked on the lens – and some markings unique to each brand.

Get yourself a good camera lens diagram of your lens, or the one you’re trying to learn to read. Put it in your office or room, somewhere that you’re going to see it often.

Make notes and write down anything important you learn along the way on the diagram.

You’ll find yourself getting familiar with all the markings and parts of the lens in no time.

Now that you know how to read camera lenses the right way – you’re ready. You have everything you need to get you on the path to better photography!

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Author

Alex Parker

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