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Stable auto-exposure with the electromagnetic aperture mechanism

Continuous shooting can pose a series of challenges to photographers, of which inconsistent exposure is a common issue. To address this, various NIKKOR lenses incorporate an electromagnetic aperture mechanism that provides highly accurate diaphragm control for more stable auto exposure control.

A closer look at the electromagnetic aperture mechanism

The electromagnetic aperture mechanism provides for a more precise control of the aperture blades. This is key for enhanced stability of auto exposure control when capturing fast-paced scenes at high frame rates, especially in environments with tricky lighting.

In conventional lenses, the aperture is controlled mechanically by an aperture lever, which may result in varying camera exposures when shooting in continuous mode. Lenses with an electromagnetic aperture mechanism, however, are able to capture consecutive shots with minimal differences in exposures as the aperture opening is controlled via digital signals that are passed through the CPU contacts of the lens. This is enabled by a small motor inside the lens that moves the blades based on digital communication between the DSLR and lens.

NIKKOR lenses that incorporate the electromagnetic aperture mechanism are marked with an E.

Enabling smooth and reliable transitions

Mechanical linkages can be damaged if the lens is not aligned properly when mounted onto the camera, resulting in inaccurate values when the aperture is stopped down.

An electromagnetic aperture mechanism in place reduces the chances of aperture failure due to mechanical faults or occurrences of mechanical jams.

The electromagnetic aperture mechanism also eliminates the need for periodical calibration to maintain proper performance, a characteristic of most mechanical devices.

Chase the action with your NIKKOR

With the electromagnetic aperture mechanism, photographers are empowered to create expertly-composed shots with consistent exposures in every frame.


Lenses with an electromagnetic aperture mechanism are compatible with selected Nikon DSLRs.