MGrayson
Subscriber and Workshop Member
Good Morning,
I'm moving a discussion of mirrors and image orientation from Behind the Scenes to its own thread because I feel like I've pulled that miraculous place too much off topic. I'll have the usual verbiage and pictures (computer drawn, alas, not photography) later.
You are correct. The reason for the asymmetry is that you must choose how to turn around inside the room. If you were in zero gravity, you could turn around the usual way, or by rotating around your hips and ending up upside-down. In that case, the image would appear reversed left-right, but not up-down.
This choice of rotational axis, and it's mandatory in all odd-dimensional spaces (and three happens to be odd), is the root cause of all mirror and viewfinder related issues.
I don't want to go into four-dimensional photography, but the image on the three-dimensional sensor (that would be a LOT of voxels) , e.g., a tintype, is NOT reversed - merely rotated. The image on the 3D ground glass, OTOH, would be appear rotated and reflected, and not just rotated, as on our 2D versions. To be precise, it's what the world would look like through a corner mirror - three mirrors arranged like the corners of a room - everything upside down and backwards.
That's it - no more higher dimensional or non-Euclidean photography. (My Ph.D. thesis was on counting the bathroom tiles of four-dimensional non-Euclidean creatures. I am not making that up. We called it "Growth Functions of Fundamental Groups of 3-Manifolds", but that's what it amounted to.)
Matt
I'm moving a discussion of mirrors and image orientation from Behind the Scenes to its own thread because I feel like I've pulled that miraculous place too much off topic. I'll have the usual verbiage and pictures (computer drawn, alas, not photography) later.
John,Not sure about the starfish, but isn’t the reason why the image in the camera obscura is not reversed left to right when viewing it a simple matter of perspective of the viewer? In other words, in this case you are viewing the image projected on the wall whereas in the case of the viewfinder you are in essence viewing from the opposite side? I suspect I must be missing something pretty basic here so look forward to being thoroughly disabused of my (il)logic upon reading your essay, abridged for photographers and lowly experimentalists such as myself.
John
You are correct. The reason for the asymmetry is that you must choose how to turn around inside the room. If you were in zero gravity, you could turn around the usual way, or by rotating around your hips and ending up upside-down. In that case, the image would appear reversed left-right, but not up-down.
This choice of rotational axis, and it's mandatory in all odd-dimensional spaces (and three happens to be odd), is the root cause of all mirror and viewfinder related issues.
I don't want to go into four-dimensional photography, but the image on the three-dimensional sensor (that would be a LOT of voxels) , e.g., a tintype, is NOT reversed - merely rotated. The image on the 3D ground glass, OTOH, would be appear rotated and reflected, and not just rotated, as on our 2D versions. To be precise, it's what the world would look like through a corner mirror - three mirrors arranged like the corners of a room - everything upside down and backwards.
That's it - no more higher dimensional or non-Euclidean photography. (My Ph.D. thesis was on counting the bathroom tiles of four-dimensional non-Euclidean creatures. I am not making that up. We called it "Growth Functions of Fundamental Groups of 3-Manifolds", but that's what it amounted to.)
Matt
Last edited: