Macro photography is a specialized genre that is very popular. Even though it’s just “close-up photography” for most people, a lot of terms and tools are emerging in the field of macro photography. Let’s take a look at a few basic
Let’s start with the most obvious: macro photography is broadly defined as close-up photography taken at life size or larger. We will talk about this in more detail in the next paragraph.
There are many half life-size (1:2) “macro” lenses on the market, and in everyday life we continue to call them “macro lenses”, but to be precise, in order to do true macro photography, you need to shoot at a reproduction ratio of 1: 1, that is, in real size.
2. Reproduction ratio
In simple terms, reproduction ratio is how the actual size of an object is related to the size of the object in the photo.
Imagine that you are photographing an object exactly one centimeter long: if this object appears on the camera as an object one centimeter long, then your reproduction ratio is 1:1 (the object is captured at life size).
If an object four centimeters long occupies one centimeter on your matrix, then in this case the reproduction ratio is 1:4 (a quarter of the natural size). Similarly, if you are photographing a 1mm long object that takes up 4mm on your sensor, then you get a reproduction ratio of 4:1 (4 times life size).
Reproduction ratios can also be expressed as magnification, where 1:1 corresponds to 1.0x, 1:4 corresponds to 0.25x, and 4:1 corresponds to 4.0x.
3. Working distance
Working distance is important in macro photography because it takes into account the physical length of the lens being used.
While the focal length is measured from the sensor/film plane to the subject, the working distance is measured from the front of the lens to the subject. This is important for a macro photographer to know because many living macro subjects, be they insects or birds, will run, fly, or crawl away if you get too close.
For example, a 1:1 reproduction ratio Nikon 200mm f/4 macro lens has a minimum working distance of approximately 29.5cm; its 60mm f/2.8 macro lens, which also has a 1:1 reproduction ratio, has a minimum working distance of just 9.65cm. This means that with a 200mm lens, you can be about 20.3cm further from the subject, than with a 60mm lens, while maintaining a reproduction ratio of 1:1.
4. Depth of field
Depth of field is also important for macro photography. Subject distance and focal length are key factors in how depth of field is displayed, and in macro photography you will almost always be working at the minimum focal length and minimum working distance.
Such a shallow depth of field can often be a plus, as it allows you to separate the subject from the background. Often, macro photographers work at f/22 or f/32 to achieve sufficient depth of field, and also use the following technique.
5. Overlay focus
Focus stacking is a relatively new technique for increasing depth of field. Although it can be applied to any genre of photography, it is best suited for macro photography.
This process uses multiple exposures of the same scene, changing the plane of focus from frame to frame. These frames are then combined (usually in post-processing) into a single frame to achieve greater depth of field than would be possible with a single frame.
Another benefit of focus stacking is that you can work at a medium aperture such as f/8 where lens performance is usually better compared to f/22 where diffraction can reduce sharpness.
The downside to this technique is that you need to work on a tripod and the subject doesn’t have to move.
6. Flat field lens
Macro lenses often have a special optical design to reduce field curvature, which is why they are called flat field lenses.
By correcting for the curvature of the field, macro lenses have a flatter plane of focus to be better suited for photographing flat objects/planes. This is also handy for depth of field, as the plane of focus will be flat from edge to edge, helping you make finer adjustments.
7. Macro Lens/Diopter
One of the easiest specialized macro tools to use is the macro lens, or diopter. It’s like a filter that you screw onto the front of your lens.
However, unlike a filter, a macro lens has a semi-convex element that helps reduce the minimum focusing distance of any lens. These lenses usually come in sets with different diopter powers, allowing you to combine different lenses to achieve varying degrees of close focus.
8. Reversing ring
Reversing rings are a unique solution for achieving close focus with any lens.
The idea behind these simple tools is to attach the lens to the camera with the reverse side, so that the rear element of the lens is facing outward and the front element is facing the sensor.
The reversing ring attaches to the lens with a filter thread (so an adapter ring may be required). It also has a bayonet mount for attaching to a specific type of camera.
This method works best with lenses that have a manual aperture ring and manual focus, however there are several automatic reversing rings available to work with more modern AF lenses.
In addition, for an even more dramatic effect, coupling rings can be used in combination with two lenses, where you flip one lens in front of the other lens to further zoom in and out.
9. Fur and extension rings
Other tools to help you achieve shorter focal lengths with any lens are bellows and extension rings. They are just as simple as the previous two methods, but generally give better results (from an optical point of view) because you don’t add extra optics to your shooting setup.
Both of these tools work on the same principle of increasing the working distance between the lens and the image sensor in order to reduce the available focal length.
Extension rings are the easier method. Like macro lenses, extension rings usually come in sets. You can use rings individually or in combination with each other.
On the other hand, the bellows is a flexible and more precise tool for adjusting the distance. While extension rings are available in 10mm, 20mm and 30mm lengths, the bellows can range from, say, 30mm to 200mm.
10. Ring Flash / Ring Light
The last couple of tools we’ll look at are ring flashes and lamps.
These tools are used in a wide variety of genres these days, but these ring-shaped lights are the perfect way to illuminate subjects in close-up shots.
Since you are often very close to the subject when shooting macro, you also often block the ability to use external light sources to illuminate the subject. Ring flashes/lamps solve this problem by attaching directly to the front of the lens to provide even and unobstructed light on close subjects.
These are fairly simple tools, and the main choice comes down to whether you prefer a higher flash output, or whether the tool is an all-rounder, that is, whether it is suitable for both stills and video.