Using Autofocus and Setting Aperture (Contax N/Contax 645)

Using Autofocus

If your camera has an AF/MF button on the back, push it to switch between autofocus and manual focus. Note that AF/MF is a push button. The rotary switch around the AF/MF button is for AEL (auto exposure lock). [Examples: A7S, A7II, A7RII, A7SII, A6300, A6400, A6500, A6600.]

If your camera has customizable buttons, press MENU, go to the Custom Operation1 tab, find Custom Key, and assign one of the buttons to AF/MF Ctrl Toggle. We suggest assigning the Focus Hold button for this purpose, which is the button on the Contax N-E Speed Booster ULTRA or Contax N-E/Contax 645-E Smart Adapter. Press that button to toggle between autofocus and manual focus. [Examples: A7III, A7RIV, A9.]

For other cameras, use the A/M switch on Contax N-E Speed Booster ULTRA or Contax N-E/Contax 645-E Smart Adapter.

Setting Aperture

With any A7 series camera, A9, A6300, A6400, A6500 or A6600, you may use the aperture ring of the lens in Aperture Priority and Manual Exposure modes by setting the switch on the adapter to the M (manual) position. In Programmed Exposure and Shutter Priority modes, the aperture ring is always ignored.

Aperture is always controlled on the camera body for other cameras.