I've received a Tokina-Special auto 135mm 1-2.8 lens and am wondering what it is I've got here - its quality and whatnot. I've searched for reviews and such on it but haven't had any luck. The only thing I've found is on the Tokina 50-135mm f/2.8 Pro DX AF. Is the lens worth hanging on to? I'm a newby to photography and am grateful for any info and/or advice anyone can offer. Thanks! j.