Pat,

"Why would a manufacturer put such an explicit statement in their literature?"

Answer: Several possible reasons.

1. Advertising hype.

2. 1983 was twenty-two years ago. Lets hope they've come to a different conclusion since then.

3. They were comparing the "A" series to the "SF" (soft focus) series of lenses, which they also made, and were specifically designed for portraiture.

4. They were referring to wide open. There is no difference in their ability to focus 3-dimensional objects when closed down to f16-22.

The statement that I questioned was your referrence to "unusual spectral interpretation" Never heard that one before.

"Flat field lenses", such as the G-Claron, Apo-Ronar, and Fuji A series, are process lens formulations that are, supposedly designed to be optimized for photographing flat surfaced objects, such as printed pages. That was Ron Wisner's point of contention.