First let’s clarify a few abbreviations:

  • AF: Auto Focus
  • ERF: Electronic Range Finder
  • OVF: Optical View Finder
  • AE: Auto Exposure

The X-PRO2 and the X-100 serie starting with the X-100T and now the X-100F have an Electronic Range Finder. It’s at the bottom right of the Optical View Finder.

The problem is that the AF is very slow when you use the ERF and showing an enlarged image in it.

According to Fujifilm, it’s because:

The Auto Exposure (for the ERF: my addition) covering the entire angle (of the view finder: my addition) cannot be carried out with the enlarged image which is in a portion of the entire angle. The camera then stops behind the scene.

&mdash: Fujifilm: ID: 19546

Basically:

  1. The viewfinder freezes while displaying the enlarged view of the ERF.
  2. The camera goes “behind the scenes” and does the AE operation.
  3. The viewfinder un-freezes and displays the updated ERF view after having done both the focus and the new exposure for the ERF.

So the question is why does the camera need to do the metering to display the enlarged section in the Electronic Range Finder?

The view within the Electronic Range Finder needs to be exposed “kind of” properly, especially if it is within shadows or highlights, so it can be seen.