Antisthenes

Yup.

Frustrated people will always find reasons to complain.

The Sofort is quite historic, as it's Leica's timid, first foray into what could /actually/ be called "medium format".

Leica's...

Consider the two meanings for "visualization" listed by Merriam-Webster:

1: formation of MENTAL [i.e. abstract] visual images
2: the act [..] of PUTTING INTO [concrete] VISUAL FORM

"Meaning 1" is...

@stefpix
> I am wondering if Sony's new lenses are designed by cutting
> corners and they all focus shift

Focus shift is essentially caused by spherical aberration (SA). A lens subject to...

@Rishi
> The lens also stopped down even for AF-S/initial acquisition
> if you pointed it a bright-ish scene - as if the camera is
> afraid of letting in too much light, which makes no sense

In...

.
> That's a 50mm lens, a standard, boring focal length. [..]
> it's something that you can put on the camera and take
> everywhwre with no high expectations.

The kind of fashionably dismissive...

Simple Definition of compliment : a remark that says something good about someone or something Simple Definition of complement : something that completes something else or makes it better As to ...

Note that discussions about the aperture bahaviour of this lens based on Rishi's interesting, but necessarily quick hands-on are fairly irrelevant.

Sony explicitly states that the A7R2 must be...

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As light field photography demonstrates, imaging systems are becoming, more and more, computational systems.

An important theoretical limit of such systems is that the mapping mechanism...

Your assertion:

"there exist bijections form R^3 to R^2, you did not have to go to countable sets"

My reply:

Such bijections are theoretical constructs — e.g. fractal — that are not computable,...

Your assertion:

"On a more mathematical note, R^2 and R^3 are not isometric, and there is nothing we can do about that."

My reply:

As explained above, nothing prevents a 2D surface from being...

Your assertion:

"There is no projection that would preserve distances - it is a trivial thing to figure out. All points on any radial way, for example, will be projected to one, which means zero...

Your assertion:

"The same "distortion free" lens makes your head look like a head of a Martian near the edges and does not preserve angles or ratios of angles/sides not parallel to the image...

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Note that, say, a 24MP full-frame sensor has a pixel pitch of about 6 microns — i.e. about six thousand nanometers. As explained above, there exist optical systems that can project a picture...

Nope. It's you who are a bit out of your depth, as demonstrated by your shallow, sweeping statements.

Your assertion:

"there is no such thing as a distortion free lens or a lens with...

On a more mathematical note, a projection is a mapping. Furthermore, it's far from established that the fabric of the Universe has the cardinality of the continuum.
At a microscopic scale — e.g....

The angles and distances of 3D objects can be preserved by photographing them using a bi-telecentric lens, as used e.g. in machine vision applications.

With such a lens, given that the entrance...

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It's thus much more rational for a lens designer to allocate the "correction budget" — i.e. ther finite number of available lens surfaces and degrees of freedom in an optical design — to...

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Examples of well-corrected, essentially distortion-free lenses include e.g. the Apo-Nikkor photoengraving process lenses.

Other examples include the reduction lenses in the scanners that...

Assume the subject is a 2D flat plane — e.g. a brick wall — and that the camera is parallel to said wall.

Assume we choose, on this wall, four distinct points, which we'll name A1, A2, B1 and...

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Volume anamorphosis will NECESSARILY happen when mapping / projecting a 3D subject to a 2D surface, like a film or an image sensor.

This is a bit similar to the "distorsion" which occurs...