LEN · Lenses
Macro Photography Basics: Magnification, Light, and Focus
Macro photography reveals a world invisible to the naked eye. This guide covers magnification ratios, lighting, and focus technique.
Diagrams
True macro means 1:1 magnification - the subject is rendered life-size on the sensor, so a 20mm insect fills a 20mm-wide full-frame sensor. Lenses advertised as macro with ratios like 1:2 or 1:3 are close-up lenses rather than true macro, though they are still useful. Dedicated macro lenses come in 60mm, 100mm, and 180mm flavours; a 100mm f/2.8 macro is the most versatile, giving working distance without being enormous.
The depth-of-field problem dominates everything. At 1:1 and f/2.8, depth of field can be under 1mm - a fraction of a bee's body. This is why macro shooters stop down hard, often to f/8-f/16, and why some stack multiple frames focused at different distances in software. Practical rules: keep the sensor parallel to your subject (a butterfly's wing, a coin), focus manually, and use focus peaking if your camera has it. Autofocus hunts badly at high magnification, so manual focus with a slight rock forward and back is the standard technique.
Light is the second battle. A macro lens at f/16 in shade needs a lot of light, and a pop-up flash produces harsh shadows and hotspots on shiny subjects. A cheap diffuser - a plastic dome or even a sheet of tracing paper over a speedlight - transforms insect and flower shots. Ring flashes give even, shadowless light that suits documentation; a single diffused off-camera flash gives more directional, dimensional light. Natural light works if you shoot in open shade or on overcast days, with a reflector to lift the shadows.
Gear and habits. Extension tubes are the cheapest way into macro: a 12mm tube on a 50mm f/1.8 gets you close for a fraction of a lens price, at the cost of light and autofocus speed. Reverse-mounting a lens with an adapter ring works too. Whatever you use, keep the camera and subject still - a tripod with a focusing rail is ideal for static subjects, and for live insects, patience and a shutter speed of at least 1/200s matter more than gear. Start in your own garden at f/11 and work outward.
Key points
- True macro is 1:1 magnification; lenses rated 1:2 or 1:3 are close-up lenses, not true macro.
- At 1:1 depth of field can be under 1mm, so stop down to f/8-f/16 and keep the sensor parallel to your subject.
- Diffuse your flash with a dome or tracing paper - bare flash ruins shiny insects and petals.
- Extension tubes are the cheapest route into macro; a 12mm tube on a 50mm f/1.8 works well.
