What do the mm mean in EXF

[33dollars]

This is one of those thing I don't get. In the EXF data it will express a measurement in mm.
What are those mm referring too ?

Here is a shot with snap focus in meters but the image is in mm
Just resized & sharpened a little.

 

[Blow-in]

Nice image....neighbours?

Are you refering to 18.3 mm? This is the focal length of the lens which has little to do with the distance the lens is focused on.....Tom will reply at greater length I expect.

Richard

 

[paulyrichard]

It's the focal length of the lens, 18.3mm = (28mm, in 35mm terms).

 

[33dollars]

So this wouldn't change if I was shooting infinity to macro ?

 

[Blow-in]

The focal length of the lens for a non-zoom is a 'locked-in' physical property of the lens. If you took it out of the camera it would still be the same. So the GR lens has a focal length of 18.3 mm which is equivalent to 28mm if the camera sensor was 'full format' (35 mm). When you focus the whole lens moves which changes the distance between the lens and the sensor to bring objects in to focus...best I can do from my phone!

Richard