Arnold
....the RMC (f/4) preceded the ATX (f/3.5-4) and was actually better, except that it focuses only as close as 0.7 m; the ATX, closer (to reach 1:3.5). There is no ATX f/4; only the RMC. ...
introduced 1978; was very expensive, equivalent to $1,542 in 1998 dollars. Herb Keppler, Popular Photography, April 1991: "Original 28-85 f/4 Tokina was large, didn't focus close, but was optically excellent and f/4 throughout. Replacement 28-85 f/35-4.5 Tokina was impressively small, light, close focusing, but optically it wasn't as good. Both are now discontinued."
From http://people.smu.edu/rmonagha/third/cult.html#tokina : Tokina 28-85mm f/4 RMC and f/3.5-4.5 ATX Tokina designed an RMC f/4 version of this lens which had a constant aperture, unlike the later ATX variable aperture version. The RMC version lacked the macro ability added to the later ATX version too. The ATX lens had a 1:3.5 macro capability and was significantly lighter (17 1/2 ounces versus 21 ounces) and slightly shorter (3 inches versus 3 1/2 inches). One big advantage of the variable aperture ATX zoom is that it used much smaller, lighter, and cheaper filters (62mm versus 72mm for the original constant aperture f/4 zoom). This filter factor is quite important if that new zoom means you have to run out and get all new filters for your new bigger zoom lens. That constant aperture may be nice, but you may pay for it twice, once for the lens and again for a new set of larger and expensive filters! On the other hand, the original constant aperture f/4 RMC zoom was proba!
bly a bit better optically, and close-focused down to only 2 1/2 feet. And it did have a constant aperture, albeit f/4. Not surprisingly, the older optically superior lens is often significantly cheaper on the used third party lens market. Seller on US EBay, 2002-10-30: "This is the excellent Tokina SZ85 28-85mm, f4 manual focus, two-touch zoom lens for Konica SLR owners. It has a solid all-metal build and an f4 constant aperture throughout the zoom range. Pictures with this lens are simply beautiful--sharp and contrasty."
