Re: filmscanners: Canon 4000 scanner VS Nikon LS4000

[Arthur Entlich <artistic@ampsc.com>]

I don't believe this is correct.  I own quite a few Kodak and Navitar 
lenses for projectors.  Kodak originally produced flat field lenses 
which were designed for flat slides, but it caused Kodak's own mounted 
slides, (paper mounts) for Kodachrome and Ektachrome to look bad.  So 
they introduced the curve field lenses to deal with this.  As you 
mention, the curve field have the disadvantage of making a slide placed 
backwards into the tray twice as blurry on the edges as a flat field 
lens would.

Art

Jim Snyder wrote:

> on 11/20/01 2:26 PM, Bill Fernandez at bill_sub@billfernandez.com wrote:
> 
> 
>>At 9:44 AM -0500 20-11-01, Bruce Kinch wrote:
>>
>>>Perhaps it's worth noting that Kodak now provides "curved field"
>>>projection lenses as standard for normal (cardboard, presumably)
>>>mounted slides in their Carousel projectors, but their older "flat
>>>field" design is recommended for glass mounted transparencies.
>>>
>>BF: If memory serves correctly this has been the case at least since
>>the 1970's.  Curved field lenses were standard, and flat field lenses
>>were special orders.
>>
> 
> Actually, I think the problem is that Kodak's original lenses curved the
> opposite way the film did, exaggerating the out of focus edge effects. The
> flat field lenses corrected this to a much improved image. Accidentally
> showing a slide reversed often meant sharp corners, but writing that was
> backwards, etc.
> 
> Jim (old-timer) Snyder
> 
> .
> 
>