Lens Adapter

A lens adapter lets a lens made for one camera mount attach to a body with a different mount. One side copies the lens mount, the other side copies the camera mount, and the ring's thickness holds the lens at the distance it was designed to focus from. Plain adapters do only this mechanical job. Electronic adapters add contacts so the camera can control the lens.

A plain adapter has no glass, so it changes nothing about the image. The lens draws exactly as it did on its original camera. Adapters with glass inside, such as speed boosters, add elements to the optical path and can soften corners or add color fringing, especially on cheap models. A poorly machined ring can also sit at the wrong distance, which shows up as a loss of focus on distant subjects.

No. The camera's body-to-sensor distance must be shorter than the lens's design distance, so there is room for the ring. Mirrorless cameras have short distances and accept most DSLR, rangefinder, and film-era lenses. Putting a mirrorless lens on a DSLR does not work, because the lens would need to sit inside the mirror box. Some lenses also have rear elements or protruding parts that hit the adapter or the sensor guard.

Only with an electronic adapter, and only when the lens has an autofocus motor. Canon, Nikon, and Sony sell adapters for their own DSLR lenses that pass focus, aperture, and stabilization signals, and they perform close to native lenses. Third-party electronic adapters between brands exist but can be slower or less reliable. Film-era manual lenses have no motor at all, so focus is always by hand.

A plain adapter is an empty metal tube with no contacts. The photographer focuses by hand and sets the aperture on the lens ring, and the camera records no lens data. An electronic adapter has contacts on both ends that relay autofocus, aperture control, image stabilization, and lens information between the camera and the lens. Plain adapters are cheap and simple; electronic adapters cost more and are made for specific lens systems.

A speed booster, also called a focal reducer, is an adapter with glass inside that shrinks the lens's image to fit a smaller sensor. A full-frame lens on a crop-sensor camera keeps most of its wide view and gains about one stop of brightness, because the same light lands on a smaller area. It works only when going from a larger format lens to a smaller sensor. Quality depends on the design, and the best ones cost as much as a lens.

Price and character. Film-era lenses often cost a fraction of new glass, and many draw in ways current lenses avoid: swirly background blur, soft glow at wide apertures, warm flare, and lower contrast. Photographers who like that look adapt Soviet, Japanese, and German lenses from the 1950s to the 1980s onto mirrorless bodies. The trade is manual focus and manual aperture, which slows shooting but suits portraits, still life, and slow street work.

Many cameras lock the shutter when they detect no lens, and a plain adapter reports nothing. The fix is a menu setting, usually called release without lens or shoot without lens. Once enabled, the camera fires normally. Exposure still works because the meter reads light through the lens. Aperture priority still works too: the lens ring sets the f-stop and the camera picks the shutter speed to match.

Through a plain adapter, no. The file records the camera, shutter speed, and ISO, but the lens name, focal length, and aperture are blank or show a placeholder value. Some cameras let the photographer enter a focal length and maximum aperture by hand for manual lenses, which then appear in the file and also help in-body stabilization. Electronic adapters pass the real lens data, so the EXIF looks the same as with a native lens.

No. Both sit between the camera body and the lens, but they do different jobs. A lens adapter bridges two mounts and, in its plain form, contains no glass. A teleconverter matches the mount on both ends and contains glass that multiplies the focal length, giving more reach at the cost of light. A speed booster is the closest cross-over: an adapter that bridges mounts and also contains glass, but its glass shrinks the image instead of enlarging it.