How to Choose a Macro Lens

Putting a macro lens on your camera lets you capture the world from a unique perspective that people often overlook. Having the right lens makes that much more enjoyable. We're offering this guide to choosing a macro lens, to help you know what to expect and what to look for.

Opening image ©Fran Ros ( @fmros ) captured with the Irix 150mm f/2.8 1:1 Macro Dragonfly lens.

What is a macro lens, anyway?

You might - or might not - be surprised to learn that there's a difference between a close-up lens and a "true" macro lens. There's one requirement for a macro lens. It needs to be able to reproduce a scene at the same size on your camera's sensor as it is in the real world. In mathematical terms, that's expressed as a 1:1 (one to one) ratio. In simple terms, we call it "life size".

So, if you shoot an object that's 1/2" tall with a macro lens, it should be 1/2" tall on the sensor, right? Not quite. First, you have to consider that how large an object appears to you depends on your distance from the object. Second, adjusting your focus changes the magnification ratio of the lens. That's why you'll find macro ratio markings on the barrel of a macro lens.

Basically, a macro lens will render an object at life size when set to the 1:1 ratio focal setting and with the object at the minimum focusing distance of the lens. Only the most technical photography tasks will call for such exact duplication, so we won't dwell on that further. The important thing to know is that some lenses are marketed as macro lenses but aren't actually capable of 1:1 magnification.

How Focal Length Affects Macro Lenses

When you understand the concept of macro photography, some things should start to make sense right away. For instance, the focal length of a lens obviously affects the image size on the sensor, too, at least from the same distance. So, it stands to reason that the focal length of a lens will affect the distance at which that 1:1 ratio is produced.

Macro lenses are available in many focal lengths, from medium wide angle to telephoto. Wide angle macro lenses are rare, since the minimum focusing distance becomes very short. Very long focal lengths can be problematic for macro work, since any movement tends to be magnified.

"Normal" (35mm - 50mm) and medium-telephoto lenses are usually well suited for macro photography. Determining the right one for your purposes depends somewhat on what you intend to shoot and what other purposes you'll use the lens for.

Why Longer may be Better

When we engineered the first Irix macro lens, we chose a focal length of 150mm. That's somewhat longer than many macro lenses and we had good reasons for giving you the extra reach.

Room to work

The 150mm focal length gives our macro lens a minimum focusing distance of 34 cm (about 13.4"), helping you avoid "spooking" live subjects like insects. It also leaves some extra clearance for supplemental lighting and a little room to make "adjustments" to the scene without disturbing the lens and camera.

Shallower depth of field

The longer the focal length of a lens, the shallower the depth of field. Macro photographers can capitalize on a shallow depth of field to help isolate and emphasize a subject or part of a subject. Our 150mm Dragonfly Macro lens lets you work with very shallow DoF wide open, with plenty of room to stop down until you achieve the most effective focus range.

Versatility

A macro lens is more useful if it has other applications. Wide angle lenses are nice for sweeping landscapes when you're out shooting nature, however as we've mentioned, they rarely work well as macro lenses.

The extended focal length makes our Dragonfly 150mm lens much more than a macro. It's a great street lens. It's also suitable for medium-range wildlife and nature photography and it makes an outstanding portrait lens, too!

Aperture Size and Diaphragm Construction

Aperture size range plays an important role in any type of photography. A wide maximum aperture means faster shutter speeds and the opportunity to minimize depth of field. A narrow minimum aperture lets you extend the depth of field when you want maximum front-to-back sharpness. Keep in mind that an extremely wide aperture may not always be effective in a macro photo. When shooting close, small subjects, you'll often need to stop down a bit to bring out enough detail. For that reason, you probably don't need to invest in an expensive lens with an aperture of f/1.4 or f/1.8. You can always use supplemental lighting or a higher ISO setting to increase your shutter speed.

The way the diaphragm of a lens - the part that controls the aperture size - is constructed makes a considerable difference in the quality of bokeh. If you don't know, that's the appearance and aesthetic quality of blurred portions of the scene. The number and shape of the blades affects the shape of the blur, particularly for bright points of light.

Irix has you covered.

We considered these features in developing our macro lens, too! The 150mm 1:1 Macro Dragonfly employs a diaphragm with 11 specially curved blades. This configuration creates a nicely rounded aperture. It produces beautiful bokeh and helps eliminate diffraction as you stop down, to retain maximum sharpness in your images. We've given it a great aperture range, from a fast f/2.8 to a super-sharp f/32.

Prime vs. Zoom

There are many zoom lenses available with macro capabilities. You'll need to decide whether a fixed focal length or zoom works best for your purposes. We can't make the decision for you, but we can list a few of the pros and cons to help you decide:

Macro Zoom Lenses offer one obvious advantage: a variable focal length. That means you can reframe your shots without the need to move and set up again. That can be very convenient in many situations. There are a few compromises you'll have to make with zoom lenses:

• Magnification ratios change when the focal length changes. You'll need to adjust your focus when you zoom in or out to maintain a constant ratio.
• More moving parts mean a greater chance of focus drift.
• Maximum aperture settings are often narrower and may not be constant throughout the zoom range.
• Usually heavier than prime lenses
• Usually more expensive than prime lenses

Prime macro lenses lack the ability to change their focal length, so in order to reframe a shot, you'll need to move. On the other hand, you'll probably be staying close to your subject for most macro photos, so the ability to move quickly may not be a major factor.

A good quality, fixed-focus macro lens has none of the disadvantages listed above. Price and weight are, of course, major considerations and so is a wider aperture. One less obvious, but important advantage is the ability to maintain the same magnification ratio from shot to shot.

By simply locking the focus at the setting you choose, you can ensure that constant magnification. That's assuming that the lens has a focus lock, as our Irix 150mm Macro lens does. Your shot then will be managed by varying the camera-to-subject distance and the aperture setting.

Communication with the Camera

Macro photography calls for a lot of concentration on your composition and focus. You may also have a subject that moves, as well as wind and camera movement to deal with.

With all of that going on, it's a bonus to be able to count on your camera's exposure system. A macro lens that allows you to use your choice of auto-exposure modes will make your life much easier. Choose one that provides electronic aperture control through the camera. Bonus tip: That will also provide the aperture setting in your EXIF data so you can look it up later.

Fine Focusing

When you're working at macro magnification, precise focus is critical. In fact, many photographers use only manual focus for macro photography, just to be sure. Even so, distances are so short at this range that finding that precise spot can be a challenge.

We engineered the Irix 150mm macro lens to overcome this issue in multiple ways. First, the focus ring rotates an incredible 270 degrees. That makes your adjustments much less "touchy".

Second, the focus ring has a wide, textured, rubber grip with a raised tab. The improved grip and added leverage make for almost effortless "nudging".

Third, the lens also supports focus confirmation. That means fine-tuning the focus is even easier.

External vs. Internal Focusing

Another important aspect of macro focusing is whether the physical length of your lens changes when you focus. Imagine carefully setting up for a shot only to have to start over because your lens creeps to close to focus on your subject. Even worse, your lens element could come into contact with something in the foreground or scare your subject away. This scenario can become a reality with an external focusing lens.

A macro lens with internal focusing is a great advantage. The elements that control focusing move within the lens housing, behind the objective lens. The lens length stays the same, so when your front element is set, is stays put even when you refocus. Internal focusing is just one more of the features you'll appreciate in the Irix 15mm Dragonfly Macro lens.

Why we think you'll choose our macro lens

We admit it. We want you to choose our 150mm f/2.8 1:1 Macro Dragonfly lens. In fact, we considered everything in this article and more when we created it. Let us give you a few more reasons to choose it:

Award-winning design: You don't need to take our word for the success of our design. In addition to outstanding customer reviews, our macro lens quickly acquired some of the industry's most prestigious awards, including the iF Design Award for 2019 and the Red Dot Award for 2019.

Irix optics: Our glass, optical design and coatings are already well-known for their sharpness and aberration control. The 150mm Dragonfly proudly continues that tradition.

Universal Stability: At macro magnification, the slightest movement can ruin your shots. To help you quickly create a rock-solid setup, we added a rigid, removable collar with an Arca Swiss-compatible foot for your tripod.

Superior exterior: Our first macro lens is also the first to sport our new Dragonfly housing. We combined the best features of our Blackstone and Firefly finishes to create a uniquely comfortable, lightweight and highly rugged exterior.

Weather sealing: You won't have to leave your macro lens behind or "bag it up" when conditions aren't ideal. Five weather seals protect this lens, to keep dust and moisture out. No need to worry when you're getting down and dirty for the shot you want.

Oh, by the way, do you shoot cinema?

Professional cinematographers know that having a top-quality macro cinema lens can add a whole new dimension to their productions. At Irix, we support their industry, too! That's why we recently launched our Cine line, with a gorgeous macro lens based on our already-proven 150mm optics !

The Irix Cine 150mm T3.0 1:1 Macro lens is already making a name for itself. It's more than up to the challenges of the cinematic industry and we think you'll want to choose it for your video productions, too!

Find Out More

Get the full story on both of our macro lenses, on the Irix USA website! You'll find specs, details, customer reviews - oh, and free shipping, too! Follow these links to the information pages:

Irix 150mm 1:1 Macro Dragonfly Irix Cine 150mm T3 1:1 Macro