I never said there was anything "wrong" with the design, it's just that AT THE SPECIFIC magnification the older designs were designed for, the pseudo-zooms are going to hard time matching the classic fixed designs, the extra elements needed for faster speed and wider focus range become a burden rather than help in terms of contrast, saturation, and flare reduction just like a prime is better at one focal length than a zoom at the same focal length. Except in this case you are comparing a FAST ZOOM to a Slower prime. Guess which one is almost always going to be better if you use the prime for what it was designed for? JCO -----Original Message----- From: William Robb [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 10, 2004 9:44 AM To: [EMAIL PROTECTED] Subject: Re: 50 or 100 mm
----- Original Message ----- From: "J. C. O'Connell" Subject: RE: 50 or 100 mm > FREE is psuedo-zoom. It is pretty obvious if the focal length varies > and it does. Pentax has made both dedicated and pseudo- zoom macros. I > believe the switch occurred when they went from F4 designs to F2.8 > designs in the early 80's. Of course any lens that "does" Macro is a > "real" Macro lens but when I was referring to the > "classic" macro lens designs I meant the fixed focal length designs > optimized for a specific closeup magnification, similar to the designs > of modern high end enlarging lenses. > Not withstanding, the macro lenses with the fixed rear element design are incredibly good lenses. I recall reading in the literature of the day when I bought the A100mm f/2.8 macro that the design allowed for superior lens performance throughout the focal range. As the lens is excruciatingly sharp from 1:1 right through to infinity (no small feat), there is absolutely nothing wrong with the lens design. William Robb
