What is a macro lens? You’ve probably seen many examples of macro photography. But understanding the nature of macro lenses can be difficult, or even downright confusing.
In this article, we’re going to break it down for you. You’ll discover everything you need to know about macro lenses.
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The Technical Definition of a Macro Lens
How do macro lenses do this?
Macro lenses are built to have a low minimum focusing distance. Most lenses can’t focus on an object several inches in front of them. A macro lens can.
When you use a macro lens, you can keep focusing until your subject looks magnified. It’ll appear huge in the frame.
Lens magnification capabilities are measured based on the size of the image on the sensor. Most professional camera sensors are 36mm in length.
If you photograph a subject that’s 36mm long, and you focus all the way in with a macro lens, you should get an image of your subject on the camera sensor that’s 36mm.
If you opened up the camera and looked at the sensor, your subject would take up the entire length.
And that would be a true macro photo.
In other words, the technical definition of a macro lens is one that displays the subject as life-size on the camera sensor. This is also known as a 1:1 magnification ratio. If a lens is able to achieve this 1:1 magnification, then it is a true macro lens and can capture true macro photos.
True macro lenses are also referred to as dedicated macro lenses. It’s designed with this 1:1 magnification capability in mind.
Most macro lenses are true macro lenses, but not all of them are. When you go to purchase a macro lens, I recommend checking the maximum magnification ratio. If it’s not 1:1, then it won’t get you true macro images.
What Are the Capabilities of a True Macro Lens?
And this comes with certain pros and cons.
Dedicated macro lenses tend to be incredibly, incredibly sharp. They’re often the sharpest lenses in a manufacturer’s lens lineup, beating out gear that costs twice the price.
This is because macro lenses are designed to show detail. They’re designed to show you everything in a scene so that it’s tack-sharp.
Even budget macro lenses do well with sharpness. The old Tamron 90mm macro lens is one of the sharpest lenses I’ve ever used, even though it’s cheap.
Note that macro lenses are often sharpest at high magnifications. This is one of the factors that separate dedicated macro lenses from macro alternatives, such as extension tubes or close-up filters.
Even if you mount them on a sharp lens, you’re just not going to see the same level of sharpness.
Bokeh refers to the background blur you get in your photos, like this:
And different lenses create different bokeh.
The best lenses create bokeh that is soft and creamy. It looks amazing, and it complements a sharp subject.
Look at the soft bokeh in this photo.
Generally speaking, macro lenses provide amazing bokeh. The Canon 100mm f/2.8L, for instance, gives gorgeous backgrounds.
Even cheaper macro lenses are known for their quality bokeh. The Sigma 105mm f/2.8 macro provides beautiful bokeh at a great price.
A big reason for this is the wide maximum aperture. Macro lenses can usually be shot with an aperture up to f/2.8. And the wider the aperture, the better the bokeh!
Image Stabilization Difficulties
The higher the lens’s magnification, the more difficult it is to capture sharp images.
This is because even small movements get magnified by a fully extended macro lens.
Fortunately, many macro lenses have built-in image stabilization. This helps counteract camera shake.
But when you’re working with a lens that doesn’t have image stabilization (and most of the budget macro lenses don’t have it), you have to be very careful.
It’s important to hold your camera in a firm grip with your elbows tucked in–or to use a tripod.
Dedicated macro lenses are plagued by serious autofocus difficulties, especially when working at high magnifications.
You see, at high magnifications, the autofocus has to work hard to pinpoint your desired point of focus. Even small changes in real-life focal points can be a huge task for an autofocus system.
Macro lenses are rarely built with fast autofocus. If you choose to shoot with the autofocus on, you’ll be stuck waiting while your lens hunts for the correct point of focus.
That’s why I recommend you avoid using autofocus whenever possible. Instead, you should use manual focus–which will allow you to focus much more smoothly and quickly. Fortunately, most macro lenses have a well-designed focusing ring, so working with manual focus shouldn’t be too much trouble.
Small Working Distance
While macro lenses have the amazing ability to focus up close, this comes with a major difficulty:
A small working distance.
The working distance refers to the distance between the front of your lens and the closest part of your subject.
So if you’re taking photos of a flower, you’ll find that the front of the lens gets very close to the flower. In fact, you’ll often cast a shadow on your subject, which can be frustrating when you’re shooting in golden-hour light.
That’s the nature of high magnification lenses. The closer you focus, the smaller your working distance.
Fortunately, you can get around this by purchasing a longer macro lens. Because the longer the lens, the longer your working distance. While a 50mm macro lens has a tiny working distance, a 180mm macro lens will give you far more room to maneuver.
Common Macro Lens Focal Lengths
Macro lenses come in three focal length groupings:
Short, standard, and telephoto.
Short Macro Lenses
Short macro lenses are small and light; they tend to be best as walkaround macro lenses. More serious macro photographers tend to avoid these focal lengths. The short working distance makes them difficult to work with.
Short macro lenses also tend to give less impressive background bokeh.
Standard Macro Lenses
Standard macro lenses tend to be the bread and butter of most macro photographers’ toolkits. These lenses range from 90mm to 105mm.
There are Canon standard macro lenses, such as the Canon 100mm f/2.8L. There are Nikon standard macro lenses, such as the Nikon 105mm f/2.8 VR. And there are Sigma, Tamron, and Tokina standard macro lenses.
Standard macro lenses are a good compromise between weight and working distance. The standard focal length keeps the lens from getting too heavy, but it also allows you a decent working distance for close-up shots.
Telephoto Macro Lenses
Telephoto macro lenses are mostly used by photographers who shoot moving subjects.
If you photograph butterflies or dragonflies, a standard macro lens might scare off your subjects. That’s why you’ve got to go in for a telephoto macro lens. This will get you close-up shots without taking you right up to the subject.
The longer your macro lens, the more you have to worry about camera shake. I recommend using fast shutter speeds or working with a tripod.
You should now know all about macro lenses.
And you should know about their benefits and their limitations.
There are plenty of great Canon macro lenses, Nikon lenses, and even third-party macro lenses out there if you’re interested.
So check them out, and have some fun doing macro photography!