Anamorphic de-squeeze shows a properly de-squeezed image (with or without surround view) on the EVF-1 and/or MON OUT when working with 2x or 1.3x anamorphic lenses. Requirement is the Software Update Packet 4.0.
Anamorphic de-squeeze includes four different modes:
Using a 2x anamorphic lens with de-squeeze turned off, viewfinder and/or MON OUT will deliver the full sensor image, horizontally squeezed by a factor of 2, so a circle is egg-shaped. The dotted lines indicate the frame lines that will result in a 2.39:1 image once the image is de-squeezed. These frame lines are 1.195:1 (2.39 divided by two = 1.195).
Using a 2x anamorphic lens with "de-squeeze 2x" enabled, viewfinder and/or MON OUT will deliver the full sensor image, properly de-squeezed, so a circle is a proper circle again. The dotted lines show the 2.39:1 aspect ratio, and you can see that you will record some extra image to the left and to the right, which can be used in post for repositioning.
If the "De-squeeze 2x" setting makes the image too small for you, you can switch to "De-squeeze 2x & magnify". In this case the image in the viewfinder and/or the MON OUT is zoomed in on the center area of the recorded image. The 2.39:1 image now almost fills the horizontally available space, leaving a little bit to the left and the right of the 2.39:1 frame. As the image, however, is zoomed in, the camera captures more image content to the left and right than shown by viewfinder and/or MON OUT. Please note that this mode is available in Standby and Record, but not in Playback mode. If "De-squeeze 2x & magnify" is set for the viewfinder and/or MON OUT and an image is played back from an SxS PRO card, playback will be "De-squeeze 2x" instead.
Specifically developed for 16:9 sensors, 1.3x anamorphic lenses do not squeeze the image by a factor of 2, but rather by a factor of 1.3. That makes a 2.39:1 image fit almost perfectly onto a 1.78:1 (16:9) sensor. For the sake of simplicity only the resulting images with surround view off are shown below. However, surround view can also be switched on.
Using a 1.3x anamorphic lens with "de-squeeze off", viewfinder and/or MON OUT will deliver the full sensor image, horizontally squeezed by a factor of 1.3, so a circle is again egg-shaped. The dotted lines indicate the frame lines that will result in a 2.39:1 image once the image is de-squeezed. These frame lines are 1.838:1 (2.39 divided by 1.3 = 1.838), which is of course very close to the 1.78:1 aspect ratio of the available pixels on the ALEXA sensor.
Using a 1.3x anamorphic lens with "de-squeeze 1.3x" enabled, viewfinder and/or MON OUT will deliver the full sensor image, properly de-squeezed, so a circle is a proper circle again. The dotted lines show you the 2.39:1 aspect ratio. As you can see, you will record just a little bit more image on top and bottom.