alanr0

Garry - my way of looking at this: Absent mechanical vignetting, the entrance and exit pupils are simply virtual images of the iris/system stop, as viewed through the front and rear elements ...

I have not worked through your calculation in detail, but you seem to be looking for a single model to predict macro performance as focus is adjusted. The "thick lens" model follows from Gaussian ...

As bobn2 said, it is more about the device construction. Doping makes a difference indirectly, in that the P and N-doping concentrations change the width of the PN junction. PIN diodes have an ...

Thanks for posting Garry. Some observations based on my own analysis: In your root-sum-of-squares expression, you appear to equate the diameter of the geometric blur, c, with the diameter of the ...

If the plane containing the two parallel lines is parallel to the image plane, then their images remain parallel. This is what is meant by rectilinear projection. Even if you tilt the camera ...

Agreed, Tom. Strictly speaking, the horizon is not a straight line, though it is pretty close if one's viewpoint is near the surface of a sufficiently large sphere. How close? On an ideal spherical ...

My apologies Tom, you are quite right. If one is about to disagree with someone on the interwebs, to avoid embarrassment one should: (1) Re-read the OP carefully at least twice.

Tom Axford said This was in the bit-mapped derivation, so won't have shown up in an automated search of his text for specific words like "assume", "assuming" or "assumption". Similarly, I said : If ...

Agreed, it is possible if the focal length varies with object distance, but that breaks one of Tom's key assumptions. Changing the principal plane separation will be difficult without changing the ...

<snip> Unfortunately, to substitute in the original equations, we need to know either x1 or x2 . In your scenario, we only know the difference. You have two equations, but at least 3 unknowns: f , p ...

Thanks for that. Unfortunately, I don't have access to the  Journal of the Society of Motion Picture and Television Engineers from 1968. The original (1998 and 2006 versions ) of equation B1 is ...

Thanks for that - I had not seen it before. It maintains consistency with the original 1997 draft, in terms of the conclusion (i.e. equation B.4), while preserving the lack of rigour and attention ...

Agreed. Well you can always talk endlessly about what you would have done to it if you had captured it.  I believe this is traditional amongst sports fishermen, and  I don't see why it can't be ...

There is a similar Annex B (informative) in both ISO 12232:2006, and an earlier pre-publication draft of the 1998 standard from October 1997. Note that the published ISO12232:2006 version contains ...

There is an argument which holds that a raw file is not an image file. This may seem like splitting hairs, and there can be some debate about this, but, for instance, ISO 12232:2019 mandates that ...

As I understand it, the numbers are calculated per-pixel, then normalised to the area of the pixel. "Pixel area" is potentially difficult to define without a detailed understanding of the ...

Which standard do you mean? The obvious candidate is the SI Brochure . The current 9th edition from 2019 includes the word "exposure" exactly once, but only in the context of ionising radiation on ...

Without equalising the post-processing so that the comparison images have equivalent tone black level and identical tone curves, I have no way of knowing if there is a significant difference to ...

<snip> To my mind, PDR is not a particularly useful tool for comparing these images. Your original point made here was that bit-shifting the output from an ISO-invariant sensor introduces ...

That makes more sense - I thought I might be missing something. You can't make changes after a reply is posted.  This is often annoying, given my fingers' inclination to type something different to ...