Sony alpha cameras always take images in aspect ratio 3:2 but you can choose a 16:9 overlay if you prefer to take images in 16:9. As the camera always saves the images in 3:2 you need to crop the images later in photoshop to 16:9. Unfortunately 16:9 is the only alternativ format you can choose and I would love the possibility to see black overlays in any aspect ratio i want.

For canon cameras there is a reverse engineered software called „Magic Lantern“. One option within this software is the possibility to create your own cropmarks / overlays. You just create a photoshop file with two layers. A white background layer and a second layer with whatever shape you want. When you copy this photoshop file on the SD Card of your camera you can load it onto your camera. The second layer with your shape will then bye shown as an overlay. It´s meant to use it for different aspect ratios but you can also draw a flower and let it appear on your camera liveview.

Here is a link to that software: http://magiclantern.wikia.com/wiki/Cropmarks

For Arri cameras you habe the following option to create costum Framelines:

http://www.arri.com/de/camera/alexa/tools/arri_frameline_composer/

For Sony cameras there isn´t such thing but there seems to be a way to build android apps and install them on the camera to create new functions. My question is:

Is it possible to built an app for sony cameras that lets you create costum overlays that show in camera live view?

Best, David