Fuji 23 1.4 WR as ‘35-50mm’ zoom

Jeff Biscuits wrote:

BeatX wrote:

Hmmm, interestint point. I didn't thought about it this way. I need to run some tests to confirm Your words, unfortunately I don't have access to any lenses than those two I have listed in my signature. But I will keep in mind to check it in the future, when there will be opportunity. Thanks

Your current lenses are fine for the test. Stand in one place, point at the same spot, and take one photo with each lens.

Then crop the 23mm image so that its width is roughly 0.7x its original value.

You should see that the location of every part of the image is the same.

For a bonus test, take the 23mm image at f/2 and the 33mm image at f/2.8. You should see that the depth of field is the same in both images.

If all else fails, consider that light travels in a straight line and then imagine straight lines emanating from your eyeball/camera to everything you can see. Then make a rectangle with your thumbs and index fingers at right-angles to each other and hold it in front of you. Move that rectangle from close to your face to far away while keeping it the same size and keeping your feet in the same place… you still see the exact same view, you just see more or less of it within that rectangle depending on how narrow a field of view you restrict yourself to.

Exactly - perspective is yet another property that has been confused by this nonsense of "equivalence" between different sensor sizes that has caused more confusion than clarity.

Photography is a process of projecting a sector of 3 dimensional space on to a plane - what we mathematicians call a projective transform. All the point on a ray from the projection point are mapped to the same point on the plane. A projective transform does not respect distance. However, it respects relative distance between points as they are mapped onto the plane. The key factor is the distance from the projection point and the plane. For a camera that translates to the distance of the camera to the focal plane.

https://courses.engr.illinois.edu/cs543/sp2011/lectures/Lecture%2002%20-%20Projective%20Geometry%20and%20Camera%20Models%20-%20Vision_Spring2011.pdf