Originally Posted by Aussie Bob II
An un-corrected system that exhibits "only" a 1 pixel(!) color smear, and that has astigmatism built-in cannot possibly be as good as a color corrected system with
Color correction in any system, particularly a cylindrical system (which is what Isco and my own systems are), should be (and is) measured in small fractions
of a pixel, the smaller the better. A 1-pixel aberration would get me hung from the nearest lamp post if I tried to pass it off as "crisp", much less "the crispest... on the planet".
Having only two elements is a trivial advantage and has nothing to do with "crispness". Each glass surface if anti-reflection coated
reflects around 0.5% of the incident light, on average. The extra 4 surfaces on corrected systems therefore, if coated (which all cylindrical systems are), will introduce around 2% extra loss of brightness, in return for better sharpness and no color aberration
I'll grant you that a vertical compression system - like the FVX200 - will take advantage of the user having to zoom the image larger
(prior to optical compression), thus increasing the numeric aperture (and hence the brightness) of the system and the final image, while constant height systems (horizontal expanders) lose a few per cent compared to the zoom method for the contrary reason, but that is not comparing apples with apples.
For a vertical compression system to work in the same way
, and with the same convenience as a horizontal expansion system - Constant Height - you would need to remove the lens for 16x9 presentations to make a true comparison, which you specifically recommend against
doing. The reason for this recommendation, I suspect, is that a compression system is inherently Constant Width
. In order to make it Constant Height
and to use the full pixel array, the user will need to both remove the lens and
re-zoom the image smaller, which kind of defeats the purpose, I think, forcing users to tinker around with zooming, which they do not have to do with Constant Height systems.
Each system has its foibles, pros and cons, advantages and disadvantages, but to claim an un-corrected prism system that only uses 3/4 of the horizontal pixels is both
"crisper and brighter" than an Isco or any other cylindrical system on the planet
- and it's a BIG planet - is not telling the full story of the process with all its "ins" and "outs".