Thanks for detailed mail Ramesh --- Joseph Tainter <[EMAIL PROTECTED]> wrote: > "Hey Joe, > > "How can you tell if you got one from a bad batch? > It doesn't sharpens up when you use smaller > apertures > at some focal lengths or what?" > > I noticed on some shots I had taken in Paris that > there was pronounced > lateral softness. It was only a few images out of a > couple of hundred, > and I was not sure of the focal length or f-stop on > those shots. So I > tested it systematically, 28, 35, 50, and 80 mm., > all f stops to 16. It > turns out that the weakness was at 50 mm. f5.6, and > a bit at f8.0. When > I got the replacement I also tested it > systematically and found it was > superb. > > The test was on a tripod, using Provia 100F. I then > scanned the images > on a Nikon LS 2000 and looked at them at 200% to > 300% magnification in > Photoshop, no sharpening. > > Then, of all things, the Tokina techs said nothing > about it being soft, > but said that it had low contrast. I had not > complained about that. A > batch went out with a bad rear element, or so I am > told. Tokina tried > first to replace the rear element group, then gave > that up and sent me a > replacement. > > So if you buy a used one, test it systematically. > > Joe >
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