Viewfinders: I am puzzled.

Started 2 months ago | Discussions thread
Tom Axford Veteran Member • Posts: 6,162
Re: It's the image in the viewfinder that matters, not its physical size.

Tommi K1 wrote:

Tom Axford wrote:

Belgarchi wrote:

The viewfinder of both the Olympus Pen-F and OM-D E-M10-III have a coverage of 100% and a magnification of 1.23x, and both use a Four Thirds sensor.

A viewfinder magnification of 1.00 means that the image in the viewfinder appears exactly life-size when using a lens of the normal focal length (25mm is commonly taken as the normal focal length for Micro Four Thirds cameras).

The eye-level viewfinder magnification is not altered by format.

The viewfinder magnification is not altered by format.

I'm not sure why you introduce the term "eye-level"?  That's irrelevant.

It is measured by using 50mm lens focused at infinity.

Only if you are using a full frame camera.  The OP is using a Micro Four Thirds camera, for which the normal focal length is 25mm, not 50mm.

That is why E-M1 has 1,48x magnification instead 0,74x. There is no equivalence as it makes it wrong.


There are many other values too, pupil distance as well eye relief, frame coverage etc that all are changing the eye-level viewfinder magnification and values.

There are as well many viewfinders:

  • Eye-level viewfinder
  • Waist-level viewfinder
  • Iron-frame viewfinder
  • Reflex sight viewfinder


The magnification value is that how much the subject is magnified through the eye-level viewfinder. E-M1 has 1,48x so it is 1,48 times larger than naked eye would see it.

That means:

  • 0,75x things appear three quarters of the size
  • 0,5x half as big
  • 0,9x nine-tenths as big
  • 1,5x halftimes larger
  • 2x two times larger

There is a shoal of red herrings here.

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