[opendtv] Re: Line Pairs/millimeter vs. Price vs. Image Format

Further:
The least expensive HDTV camcorder, with lens, is $499; the most expensive is some three factors of magnitude greater. The least expensive uses a 1/2.5-inch imager; ones with 2/3-inch imagers are much more expensive. Economy is not a good indicator of quality. 

TTFN,
Mark


Mark Schubin wrote:
For a fixed picture resolution, it is much easier to design a large-format lens than a small one. 

TTFN,
Mark


dan.grimes@xxxxxxxx wrote:
Mark Schubin: "Are you saying it's easier to make a lens that can provide 100 lp/mm lens than one that can provide 38 lp/mm? You'll have to do a lot of explaining to convince me of that."
By no means! I'm saying that it is more expensive to make a lens to cover a larger format area and have 100 lp/mm than to make a lens that covers a small format area and have 100 lp/mm. When I first entered the discussion, I did not know that the discussion of resolving power was in relation to a fixed imager matrix.
If we consider other qualities of the lens, such as contrast, MTF, even distribution, various distortions, etc., is it not more complicated to design the same qualities into a large format lens compared to a small one? Perhaps I am wrong on this. I gathered my knowledge while working with film where I spent a lot more money trying to cover 70mm film stock than to cover 35mm film stock. In the imaging department I was in, reduced resolution for a larger image area was not acceptable. And I worked mainly with fixed focal lengths rather than zooms.
Educate me on video lenses. When I compare a lenses to cover the 2/3" video imagers to ones that cover 1/2" imagers while claiming the same relative qualities, the 2/3" lens costs a whole lot more. Perhaps they really don't have the same qualities? 

Dan Grimes







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