What a Macro Extension Tube Does
A macro extension tube is a hollow cylinder that fits between your camera body and lens. By moving the lens farther from the sensor, it shortens the minimum focusing distance and increases magnification. Unlike close-up lenses that screw onto the filter thread, an extension tube adds no extra optics, so the image quality stays true to your lens.
The Fotodiox Pro Automatic Macro Extension Tube for L-Mount Alliance mirrorless cameras is a 35mm section built from all metal. It maintains full electronic communication between lens and body, so autofocus and auto-exposure continue to work normally.
How to Set Up the Extension Tube
Mounting the tube takes only a few seconds. The steps below assume your camera is turned off and the lens is clean.
- Remove the lens from the camera body: Press the lens release button and twist the lens off as usual.
- Attach the extension tube to the camera: Line up the mounting index on the tube with the camera's L-Mount mark and twist until it clicks into place.
- Mount your lens onto the tube: Align the lens's mount index with the tube's rear mark and twist to lock.
- Power on and check operation: Turn the camera on. Autofocus and aperture control should function as if the lens were attached directly.
Understanding Magnification Gain
The increase in magnification depends on your lens's focal length. The formula is simple: magnification gain equals extension distance divided by focal length. For a 35mm tube on a 50mm lens, the gain is 0.7X. Add that to your lens's native magnification — if the lens already gives 0.15X, you get roughly 0.85X total.
Extension tubes work best with short to medium focal lengths. Telephoto lenses benefit less because the same extension distance gives a smaller relative gain. The tube is also less effective on lenses that already have a lot of built-in extension for close focusing.
Fotodiox Pro 35mm Extension Tube at a Glance
- Fotodiox Pro Automatic Macro Extension Tube, 35mm Section - for L-Mount Alliance Mirrorless Cameras for Extreme Close-up Photography: 35mm extension length for L-Mount Alliance mirrorless cameras This specific length is a good middle option for noticeable magnification gain without making working distance too short.
Fotodiox Pro Automatic Macro Extension Tube, 35mm Section - for L-Mount Alliance Mirrorless Cameras for Extreme Close-up Photography - Fotodiox Pro Automatic Macro Extension Tube, 35mm Section - for L-Mount Alliance Mirrorless Cameras for Extreme Close-up Photography: All-metal construction with smooth surfaces for effortless mounting Metal build feels solid and holds alignment reliably over repeated use.
- Fotodiox Pro Automatic Macro Extension Tube, 35mm Section - for L-Mount Alliance Mirrorless Cameras for Extreme Close-up Photography: Maintains electronic functions including auto-focus and auto-exposure No need to switch to manual metering or focus; the camera and lens communicate normally.
- Fotodiox Pro Automatic Macro Extension Tube, 35mm Section - for L-Mount Alliance Mirrorless Cameras for Extreme Close-up Photography: Can combine tubes for various macro ratios If you own multiple sections, stacking them increases total extension and magnification further.
What Happens to Exposure and Stability
Adding an extension tube increases the effective aperture, which reduces the amount of light reaching the sensor. Your camera will compensate automatically in an auto-exposure mode by using a longer shutter speed or higher ISO. In manual mode, you'll need to adjust these settings yourself.
The extra magnification also magnifies camera shake. A tripod is recommended for sharp results, especially when working at high magnification ratios. If you handhold, use a fast shutter speed or image stabilization if your lens or body supports it.
Practical Tips for Framing and Focus
With the tube attached, your closest focusing distance decreases. If the subject is not in focus, move the camera closer or farther until it sharpens. Different lenses require different working distances, so experiment a bit.
Extension tubes work best with lenses that have a native focusing range that already goes reasonably close. Try a few lenses to see which combination gives you the composition you want.
