Changing Iris

Iris display

Many cameras do not support apertures faster than (numerically smaller than) f/1.0. Therefore, with a Speed Booster, the boosted aperture is displayed on the LCD screen when a slow lens (f/1.8 or slower) is attached. If a fast lens (f/1.4 or faster) is used, the original pre-boost aperture is displayed, even though the actual aperture used is faster. Please take this into account when transferring exposure settings from a light meter.

Tip (for Blackmagic cameras with active MFT mount): the most common cause of failure to control the iris or display the iris value on a Blackmagic camera is a stuck lens release lock button. With the lens and the Speed Booster or Smart Adapter still attached, depress the lens release lock button of the camera body once, and after that communication between the Speed Booster and the Blackmagic camera will be restored with iris operation becoming functional again.

Changing iris on JVC and Panasonic

You may use either the camera body's controls to change iris, or use the jog lever on the Smart Adapter / Speed Booster (except Speed Booster S, or when using Canon CN-E 18-80mm T4.4 L lens).

Set camera to A (aperture priority) or M (manual exposure) mode and flick the jog lever upward or downward to change iris using the jog lever on the Smart Adapter or Speed Booster.

Push jog lever inward to turn off iris control with the Smart Adapter or Speed Booster.

If jog lever is pushed inward for a second time, iris control with the Smart Adapter or Speed Booster's jog lever is turned on again.

With a variable-aperture zoom lens, iris value changes whilst zooming. With a f/4-5.6 lens for example, if iris is set to f/11 at the widest zoom position using jog lever, iris will become f/16 when zoomed to the maximum position.

The aperture you set with either method does not take effect in photo mode (A, M) until the moment a photo is taken. In movie mode (if your camera has a dedicated movie mode) the aperture you set takes effect immediately.

With Canon CN-E 18-80mm T4.4 L lens​, set the IRIS A/M switch to A to control iris from the camera body and set it to M to control iris from the lens' iris ring.

Changing iris on a passive MFT mount camera such as the original Blackmagic Cinema Camera

Note: Speed Booster S does not support passive MFT mount. The earliest batch of Speed Booster for BMPCC (Blackmagic Pocket Cinema Camera) may require modification before passive MFT mount can be supported. Talk to Metabones technical support for service.

Connect a 5V power source (not included) capable of supplying at least 1A to the micro USB port. Flick the jog lever upward or downward to change iris.

Push jog lever inward to set lens to wide open. Push jog lever inward again to return to the previous iris value.

Auto Iris

We recommend against uing auto iris/aperture during video capture, such as the P (Program) and S (Shutter Priority) modes. EF mount lenses adjust iris in 1/8th stop steps which may result in visible disruption in the footage or oscillation of the iris. Use A (Aperture Priority) or M (Manual) exposure modes. This limitation does not apply to supported Canon Cinema EOS lenses (CN-E) which allows for a much finer iris adjustments. 

Cinema EOS Lens

With Cinema EOS lenses such as CN-E 18-80mm T4.4 L, if the IRIS A/M switch is at the M (manual) position, the following functions may not work:

In A and M exposure modes on Panasonic, and on JVC, display is in F-stops, not T-stops.