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Discussion Starter · #1 ·
In terms of the trade-offs of vertically amplitude squeezing vs anamorphic lens for widescreen 16:9 projection, what are the performance trade-offs?


1. Faster phosphor wear is a known as a minus for vertical amplitude squeezing.

2. Lost light using anamorphic lens (8% to 40%) depending on lens design


But how about the "wasted brightness" myth of using vertical amplitude adjustment?...With the following assumptions, this "wasted brightness" myth may be false with a crt. Assumptions:

A. Brightness is a function of the number of electrons hitting a number of phosphor at a given potential (voltage).

B. The number of phosphor molecules "lit-up" is the same

C. The vertical lines of resolution are the same.

With the above assumptions, I conclude that the brightness will be conserved (i.e. not wasted) with the trade-off of accelerated phosphor wear.


Additional considerations or assumptions missed that will make the conclusion different?


The "wasted brightness" and "wasted resolution" are facts with digital projectors when not using an anamorphic lens but not necessarily with crt's.
 

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"C. The vertical lines of resolution are the same."


But if you are using a greater percentage of the raster vertically the sweet spot of the projector isn't the same. You now have more space so you should be able to run more lines without overlap. Hence higher resolution and more brightness if you take full advantage of the additional raster area (with more lines) and it was being either optically compressed vertically or optically stretched horizontally.


If you think about it (or draw it out) it is the same idea as it is on a 4:3 digital just that there is no fixed number of lines on a CRT. But there is a sweet spot which is a certain number of lines for a given raster image size. Increase the raster image size vertically and you can have more lines/resolution and correspondingly more brightness.


Shawn
 

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Discussion Starter · #3 ·
Thanks for pointing it out.

In my assumptions, I should then add:

D. Line height:length ratio is reduced with a panamorphic lens and therefore offers better resolution (i.e. no overlapping of lines).


But would not the conclusion remain the same concerning brightness?


"With the above assumptions, I conclude that the brightness will be conserved (i.e. not wasted) with the trade-off of accelerated phosphor wear."
 

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It's all academic until somebody comes up with a practical anamorphic lens design.
 
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