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.
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).
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.
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.
We recommend against uing auto iris/aperture during video capture, such as the P (Program) and S (Shutter Priority) modes. Canon 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.