This doesn’t happen very often, but B&H Photo actually has a Sony FE 400mm F2.8 GM In-Stock!
Not only will this replacement foot fit directly into any Arca-Swiss compatible quick release plate, but my fellow Sony Artisan Colby Brown noticed that its low-profile results in over an inch of depth reduction verses the stock lens collar foot.
• Arca-Type Compatible Replacement Foot
• Anodized 6061 Aluminum
• Provides Rigidness and Stability
• Reduces Flex and Vibration
• Lower Profile Provides Better Balance
• Optional Safety Stop Screws
Sony a9 Firmware Update 3.10 adds FE 400mm F2.8 GM OSS Lens support and improves overall stability of the camera
This update (version 3.10) provides the following benefits:
• Adds support for the SEL400F28GM lens
• Adds the Silent priority option to the Aperture Drive in AF menu Note: When using the Silent priority option, the sound of aperture drive will be reduced. The Auto Focus may become slower when the Silent priority option is selected
• Improves overall stability of the camera
Benefits provided by previous updates and included in this version
Mac Users Please Note:
If you’re running Mac OS 10.13 or 10.14 you must first run UpdateSettingTool.
[Please Note: UpdateSettingTool replaces Mac OS 10.13 Driver Loader for this update.]
Next, click on the Resources Folder, click on “SystemSoftwareUpdater” to begin the firmware update.
Before Updating Firmware Please Read:
Lightroom Classic CC 7.5 / LR CC 1.5 & LR for iOS & Android add Sony RX100 VA & VI Raw Support and Lens Profile Support for the soon-to-ship Sony FE 400mm 2.8 GM OSS lens