Extension tubes are one of the most affordable ways to achieve macro photography — they cost $20–80 vs. $400–800 for a dedicated macro lens. They add no optics (no quality loss), just physical distance between lens and sensor, allowing closer focus and higher magnification. The tradeoff: you lose infinity focus and some light.
Lens & Extension Setup
0.25 = 1:4, 0.5 = 1:2, 1.0 = 1:1 (true macro)
Stack tubes: 12+20+36mm for common Canon/Nikon sets
Macro Results
How to Use Extension Tubes for Macro Photography
Extension tubes extend the minimum focus distance of your lens, enabling higher magnification. The formula for added magnification: extension length ÷ focal length. A 25mm tube on a 50mm lens adds 0.5× — if the lens focuses to 0.1× at its closest, you now get 0.6× with tubes. This is more than enough for detailed insect, flower, and product photography.
Compensating for Light Loss
Extension tubes cause significant light loss at high magnifications because the lens projects light over a larger area. At 1:1 magnification, you lose exactly two stops. Your camera's TTL metering automatically compensates in Aperture Priority or Program mode — the camera measures light through the lens and adjusts shutter speed accordingly. In manual mode, apply the effective aperture correction calculated above.
Choosing the Right Focal Length
Longer focal lengths give more working distance between lens and subject at the same magnification — critical for photographing living insects that are easily disturbed. A 100mm macro lens with 25mm extension gives more subject distance than a 50mm with 25mm extension at the same magnification. Working distance is approximately: (focal length × (1 + native magnification)) — check your specific lens's minimum focus specifications for exact calculations.
FAQ
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What are extension tubes?
Extension tubes are hollow rings that fit between your camera body and lens, moving the lens farther from the sensor. Moving the lens forward allows it to focus closer, increasing magnification for macro photography. Unlike close-up filters, extension tubes don't add optical elements, so they don't degrade image quality. They do cause light loss that must be compensated.
How much do extension tubes increase magnification?
Added magnification from extension tubes equals the extension length divided by the lens focal length. A 25mm tube on a 50mm lens adds 25/50 = 0.5x magnification. If the lens already focuses to 0.15x, combined magnification is 0.65x. A 50mm tube on a 100mm macro lens (1:1 at 0mm extension) would give 1.5x magnification.
How much light do extension tubes lose?
Extension tubes cause light loss proportional to magnification. The formula: effective f-stop = marked f-stop × (1 + magnification). A lens at f/5.6 with extension tubes giving 0.5x magnification has effective f-stop of 5.6 × (1 + 0.5) = f/8.4 — approximately one stop of light loss. At 1:1 magnification, you lose two full stops.
What extension tube lengths are common?
The most common extension tube set for Canon EF and Nikon F mounts includes 12mm, 20mm, and 36mm tubes (total 68mm). Tubes can be stacked in any combination. For mirrorless systems (Sony E, Fuji X, Canon R, Nikon Z), tube sets typically include 10mm and 16mm tubes. Manufacturer extension tubes maintain autofocus; third-party tubes (Meike, Kenko) are cheaper but may disable AF.
Can I use extension tubes with any lens?
Extension tubes work with any lens that physically mounts to your camera. They work best with standard and telephoto lenses (50–200mm). Wide-angle lenses (under 35mm) gain much less magnification per mm of extension and the working distance can become impractically short. They don't work well with zoom lenses at wide focal lengths. Dedicated macro lenses (90–105mm) combined with extension tubes can achieve 2:1 or higher magnification.