OK - I'll eat crow here. A couple of years ago I ran some tests with the 1.7x AF adapter and was disappointed with the results. It did not stack up to the 1.4x-L and 2x-L teleconverters, and the AF, which worked fine with a 50 mm lens, did not seem to be effective with longer lenses.
Last weekend and again today I decided to reconsider this, and I put the 1.7x onto the 400 f2.8, and shot some birds. Looking at the results, I have to admit I was wrong! The slides are very sharp. They don't have the great tack sharpness of the 400 f2.8 alone, or even with the other TC's, but they are still more than acceptable and better than many other lenses sans teleconverter. When I tested the AF with the 400 f.28 I was working with a subject fairly close up, and the narrow DOF really wreaked havoc on the adapter's AF ability. In real field work, while some pre-focusing is needed the AF works quite well. I even managed to get some sharp shots of birds in flight. The 400 f2.8 and 1.7x make a pretty decent 680 f4.5 AF setup, though pre-focusing when shifting to subjects more than a few meters is a must. I stand corrected - and I'm glad the folks on this list kept sharing their assessment of this device. That's what got me to go back and try it again. - MCC - - - - - - - - - - Mark Cassino Kalamazoo, MI [EMAIL PROTECTED] - - - - - - - - - - Photos: http://www.markcassino.com - - - - - - - - - - - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
