IMPORTANT: This article applies only to specific products and/or operating systems. Check the Applicable Products and Categories section of this article before starting these steps.
When an astronomical telescope or microscope lens that does not communicate signals with the camera is attached, the shutter cannot be released if the Release w/o Lens option is set to Disable in the Setup menu. When attaching these types of lenses, set the Release w/o Lens option to Enable.
Also, when an astronomical telescope or microscope lens is attached to the camera, change the shutter speed for exposure adjustment. (The aperture value is not displayed.)
IMPORTANT (DSLR-A900/DSLR-A850 ONLY): The latest firmware update for the DSLR-A900 and DSLR-A850 adds a Release w/o lens option to the camera menu. Downloads are posted on your model support page.