Camera Compatibility The Sony Cyber-shot RX100 Mark IV differs from the III slightly in camera thickness. The newer Mark IV camera can be used in the previous housing version made for the Mark III, Product Number 6116.12. All controls are operable in this installation with the exception of the rear control dial, which must be set to the inactive position. The rear dial control may be adjusted for the Mark IV camera by installing a washer underneath the control knob. Adjustment washers may be purchased through an Authorized Ikelite Dealer. This newer housing features improved ergonomics like a front-loading camera system and improved rear dial control. Continue reading for a full explanation of new features. The RX100 Mark III can be used in this housing with the exception of the rear control dial. Older RX100 Mark I and Mark II cameras are not usable in this housing due to differences in lens and control placement. Ergonomics A new slide-in, front loading camera mounting tray makes this housing a breeze to set up and shoot. Controls are provided for all important camera functions including a re-designed, spring loaded rear dial control. Rear push button controls are laser engraved for identification with a new bright red push button for the video record start/stop. A sensitive shutter lever makes it easy to half-depress the trigger for focusing and metering. Use the camera's built-in Wi-Fi feature to download photos to another device without