Everything you need to know about macro lenses

Having a macro lens in your food photography kit will allow you to look at your food in new, creative ways, creating some jaw-dropping, stop in your tracks images. Who doesn’t want that?

But what is a macro lens?

I asked you all on Instagram what your biggest challenge was when it came to macro food photography, and the most common answer was nailing focus – I hear ya!

In this post we’re going to look at what makes a macro lens different, and how to use it so you’ll be able to create those tack sharp, beautiful macro food shots you’re just dying to create.

What makes a macro lens different?

A macro lens is a special type of camera lens that has the ability to work with very short focusing distances, taking sharp images of very small subjects.

A true macro lens has a magnification ratio of 1:1 (or greater), and a minimum focussing distance of around 30cm.

So what does that mean?

A magnification ratio of 1:1 means that the ratio of the subject size on the sensor plane is the same, or greater than the actual real life size of your subject. That’s what makes macro lenses able to take those super sharp, close up images of things like insects.

If you see a lens with a magnification ratio of 1:1 or 2:1 or 3:1 etc… it’s a macro lens.

If the magnification ratio is 1:2, 1:3, 1:4 etc… it’s not a macro lens.

But macro lenses aren’t only good for shooting close up detailed images. Depending on the focal length you choose, your macro lens also makes an incredible portrait lens, which is ideal for food photography.

Related: How to choose your food photography lenses

Choosing the Focal Length of your macro lens

When choosing a macro lens, the first step is to know whether you’re shooting on a full frame or a crop sensor camera.

A lens on a crop sensor camera will act like the focal length it is, multiplied by the crop factor of the camera. For example, if your crop sensor camera has a crop factor of 1.6x then a 50mm lens will act like the following:

50 x 1.6 = 80
Therefore the equivalent focal length = 80mm

When I was working with a crop sensor camera, I used a 60mm macro. This acted like a 90mm on my crop sensor Canon, allowing me to get a shallow depth of field in my photos, as well as a tight crop.

However, on a full frame, if you were to use a 60mm macro, you wouldn’t get the same tight crop effect as well as the depth of field.

In these two photos, I’ve shot the same scene at the same angle with a 90mm lens, and a 55mm lens, so you can see the effect this has on the photo. Even though the front of the baking tray is in the same position in both photos, the field of view is much wider.

Neither of these focal lengths are “right” or “wrong”, but a tighter crop typically produces a more visually pleasing composition for these kinds of shots of small subjects.

It’s important to note that when you’re shooting the kind of photo above (ie. not the super close up range photos), you’re not actually using the macro capabilities of the lens – at this point it’s acting in the same way as any other 90mm lens.

So why would you bother buying a macro? Well… simply for versatility. By having the option to create beautiful, tightly cropped compositions and super sharp, detailed close ups, you can do a LOT more with just one lens.

Now I shoot with a full frame camera, I’ve changed my macro lens from a 60mm to a 90mm. This allows me to take those 45° angle shots with a really shallow depth of field, and a lot of focussed detail on the top of things.

Minimum Focus Distance

The Minimum focus distance of a lens determines how close you can be to your subject with it still in focus.

Generally speaking, the longer the focal length, the further you must be from your subject to be able to focus on it.

For example, the Canon EF 100mm f/2 USM (not a macro lens) has a minimum focus distance of 91cm, whereas the Canon EF 100mm f/2.8 Macro USM has a minimum focus distance of 31cm.

This means if you were shooting with the 100mm f/2 (not macro), you would need to be at least 91cm away from your subject to even be able to focus on your subject.

Whereas with the 100mm f/2.8 macro lens, you could be anywhere from 31cm away and create a tack sharp photo.

This gives you an extra 60cm of space to play with in your compositions. So more than just those super close up shots, you can create completely different compositions with the macro lens and still have your subject in focus.

Photos like this of these cupcakes just aren’t possible without the macro lens.

Magnification

A macro lens has a magnification factor of 1.0x or 1:1, which allows it to reproduce a life sized image of your subject on the camera’s sensor.

This means you can get really, really close to something and it will still be in focus.

Sometimes you will see lenses that have a magnification ratio of 1:2 labelled as “macro”, but a true macro lens has a magnification ratio of 1:1.

Depth of Field (DoF)

One important thing to keep in mind when doing macro photography is that the DoF is very limited when shooting at close range.

In order to create images where everything in your scene is in focus (ie. sitting within the DoF), you’re going to have to use a much narrower aperture (higher F-Stop number), to get the same effect of the depth of field you would at normal range.

In macro photography, we kind of need to throw out all our preconceived notions of what a “narrow” and “wide” aperture are. To achieve the same look we are used to getting at f/5.6, we might need to use f/16 when working with close range aperture.

In these examples of frozen raspberries taken at close range, you can see the difference in how much of the shot is in focus, even at narrow apertures like f/14. Particularly look at the raspberry on the top left to see the difference in the DoF, even at f/8 we’re seeing a lot of background blur.

At this type of magnification, it doesn’t take much for things to start to go soft. Getting the majority of your subject on the same plane of focus will help you keep as much of it as sharp as possible. Many macro shooters employ a technique called “focus stacking” to combat this softness, but that’s a topic for another post!

Want to know more about the Plane of Focus? Check out this post from my dear friend Rachel.

Stability

I consider a tripod a must in food photography the majority of the time. Not only does it allow you to nail down your compositions, but a good tripod will hold your camera steady so your shots are clear and sharp.

Having your camera on a stable base will also allow you to stop down your aperture and shoot with a slower shutter speed so that you can get more of your subject in focus, and compensate for your lighting situation.

Being able to use a longer shutter speed will also let more light in, which is useful when shooting in darker places (e.g. using natural light in the middle of winter.), and when shooting at very narrow apertures like f/18.

Want to learn more about using manual mode? Check out my FREE 5 day e-course “Manual Mode Essentials”

Focus

Due to the magnified nature of macro photography, nailing focus is incredibly important – plus this is the thing that most of you said you struggle with in macro food photography on Instagram.

When you’re capturing such a fine amount of detail on your food, the smallest adjustment in focus can make or break your photo.

While most macro lenses have built-in autofocus, I really recommend you shoot in manual focus mode. Manual focus allows you to manually define exactly where the plane of focus lies relative to your camera’s sensor.

If you do prefer to use autofocus, using single point (often labelled as AF-S) is the most accurate way to do this in food photography. This will allow you to select the specific point on your sensor that your focus point should be, allowing your camera to accurately focus at that distance.