Welcome to part two of picking your first digital camera for photography. In part one we looked at the advantages of having an ILC and how to pick the body. We also briefly covered sensor sizes, which will come in handy when understanding lenses.

Contrary to what you might think, most of the perceived image quality comes from the lens, and not the camera. It’s worthwhile to invest a good portion of your budget in a good lens. As a beginner you might not be able to see the difference between good glass and cheaper glass but in time your eye will develop and you will be able to appreciate the difference.

In order to make an informed decision when it comes to picking your first lens, you must have a basic understand of the following three elements, listed from simplest to more complicated:

Lens Mount
Aperture
Focal Length

Lens Mount

At the bottom of each lens is a lens mount. It’s a screw-like piece of metal which fits snugly into your camera’s body. There are many different types of lens mount (in most cases each manufacturer has their own, sometimes more than one) but the only important thing is that it matches your camera’s.

Luckily, as it’s one of the most important things - the lens mount is usually written somewhere quite high on the description of the product. Below is a slide show of several popular photography equipment suppliers and where the lens mount is listed.

Note: be careful with Amazon, I’ve found lots of pages to have been auto-filled incorrectly.

Here is a list of popular camera manufacturers and the names of their respective lens mounts for each sensor size.

Some manufacturers, like Sony for example, have the same lens mount across their sensor line-up. This is cool because you can use the same lens on multiple sensor sizes without buying an adaptor. However, the effect of that lens will differ across the sensor sizes - more on this later in the focal length chapter.

Aperture

Great stuff, now that you understand lens mounts, you are making progress. You won’t be in the awkward situation when your lens doesn’t fit your camera. The next fundamental component of the lens we must learn is called the aperture.

As the aperture opens, more light comes in. Notice how we can open and close the aperture blades until we reach out desired diameter.

Aperture refers to the opening, the hole, in the lens which lets light through to the camera sensor. The wider the opening, the more light can enter the sensor. This is a good thing when shooting in low light conditions.

Additionally, the wider the opening, the thinner the area in focus will be. This comes in advantage when you want to create subject to background separation. If you are buying your camera primarily for portraits, a wider aperture will be important.

Aperture is listed in f-stops. They represent an approximation of the amount of light that reaches the sensor. Here are common f-stops values you will see on most lenses. Each represents a doubling of light that reaches the sensor, as you either close or widen the aperture.

The smaller the f-stop, the wider the opening, the more light. Although having a wider range of f-stops makes your lens more versatile, it also adds complexity to the design. This in turn, makes the lens usually heavier and more expensive. You will have to find a compromise between cost, weight and the ability to take in light.

The f-stop is always written in the name of the lens. Look back to the example screenshots of online stores. Can you see where the f-stop is written?

Focal Length

Great, we can now look at the correct lenses for our camera body, and we also have a fundamental understanding of aperture. We will now look at the last element: focal length.

Focal length is the length (distance) between the rear-most glass element of the lens and the sensor (simplification), once the lens is mounted on the body. This defines how wide or zoomed in the frame will appear. The technical term is Field of View (FOV).

The focal length is always written on the lens, usually twice. It’s that important. It will heavily influence how you compose your frames.

The focal lengths available on this full frame zoom lens.

In the not-to-scale example above, you an see that although the focal length stays the same, the FOV changes with the size of the sensor

The focal length IN COMBINATION with the sensor size determines the field of view. This is why when you see a MFT lens with a focal length of 25mm, it will give you the SAME field of view as a 50mm full frame sensor.

Here is a table so you can see an overview.

Notice they are not exact divisions of each other. Outside of full frame, there is no real standardization.

Although I recommend against getting a Full Frame camera as your first digital camera, it is the standard way to describe a particular field of view. The size of the sensor is the same as a frame of 35mm film so the history of how to refer to that focal length is more established.

Fixed Focal Length vs Variable Focal Length

There are two types of lenses (simplification). The first type being a lens with a fixed focal length, (ie it doesn’t change) often spoken of as a Prime lens. The second type has a variable focal length - or for short; a Zoom lens.

Prime Lens

A prime lens has a fixed focal length. The field of view doesn’t change. Naturally you can “zoom in” digitally later.

The benefit of this is that you get a lighter, smaller and cheaper (for equivalent image quality) instrument. They usually have a wider aperture, too. However the biggest reason I recommend a prime lens for a beginner is ironically because of its limitations.

When you are staring out (or even intermediate level) it's ironic that the limitation of a fixed FOV is a benefit. It allows you to more easily train your mind to learn how your lens sees. Once you learn, your brain will start to pick up compositions without even looking through the viewfinder. Learning skills like this is important in the early stages of your photography journey. Seeing your skills improve is one of the most rewarding feelings about photography.

Zoom Lens

The glass elements within the lens can move. Allowing you to optically zoom in and out. This is better than digitally zooming as you might do with your phone. In a digital zoom, you get closer to the pixels, showing you what the image is made of and ruining the magic. In an optical zoom, the focal length changes, which as you now know, changes the FOV.

A zoom offers you more ways to compose the same scene. This is great if you are shooting landscapes where moving closer would mean walking miles. If you are getting a camera primarily for landscapes, go for a zoom. If you are just starting out however, and landscape is not your one true love, then go for a prime lens.

Recommendations

You now know all the important fundamentals for picking out an appropriate lens. Here are my recommendations.

A word on portability.

Similar to how I recommend a portable camera for beginners, it’s not surprising that I recommend focusing on portability for your lens, too. It shouldn’t be the most important aspect, but if your camera and lens are a pain to carry with you, then you won’t be inclined to use them.

Anything near 120g to 200g will be appropriate for MFT or APS-C prime lens.

Do I need the widest aperture possible?

Although having a wide aperture is helpful, most beginners would do better to focus on weight and size rather than the absolute widest aperture possible. Usually as apertures become wider then the weight and size increase.

An aperture with f2 will be enough for beginners.

Which is the best focal length to start with?

50mm equivalent (approx. 35mm on APS-C, 25mm on MFT) is a great focal length for your first lens. The FOV it offers is wide enough for broader compositions but also tight enough for when you want to compose around a subject - like a person.

35mm (full frame equivalent) is another great choice because it’s very close to what the eye sees. This means you are already used to composing at this focal length. However because it offers a wider FOV than 50mm, it’s harder to compose with as there will be more elements in the frame.

If you want to shoot landscapes primarily, go with a zoom. Unless capturing animals is your thing then go for a “Standard Zoom” which uses the focal length range of 24-70mm on full frame. Remember to convert that to your camera sensor’s size.

Lastly, regarding zooms. You might be attracted by the draw of having a really wide zoom range. I would advise against this. Yes, it does give you more options, composition-wise, but it comes at a cost for equivalent image quality at that price point. I would get a maximum of around 3x zoom.

How much should I spend?

When it comes to second-hard prime lenses, I would look for something around 340€/290£/370$. It will be more for zooms because of the added complexity of the design.

Conclusion

Good job getting through all that. Both cameras and lenses are very deep subjects but with what you now know, you know enough to make an informed choice and most importantly start shooting! Once you start taking pictures, everything will start making more sense. Let me know in the comments what you would want to learn next.

Picking your First Digital Camera (Part 2/2)