Using a 1.7x Convertor with DA* 50-135

I am thinking of extending range with the 1.7x Teleconvertor. Reading some reviews it suggests that this is primarily designed for 'prime' lenses. Is this the case and any one got comments. I assume it takes the AF function from the lens and takes control..

I've tried my 1.7 with my 50-135 once or twice and have generally been rather disappointed with the results. The 50-135 gives such lovely images that adding in the teleconverter rather spoils them. On the other hand, I have only tried this once or twice, and never using a tripod, or trying to adjust the focus-wotsit so I wouldn't say you cannot get good results, just that it isn't quite as easy as just bolting it on and away one goes.

K.

The AFA 1.7X does "take control" of AF functioning (so that the actual lens, even if it's an AF lens, is really being used as an MF lens). In fact, one of the neat things the 1.7X does is to limit the focusing range with AF lenses that have long focus throws, so that they can "hunt" less (assuming the light is bright enough to compensate for the TC's "darkening").

I have no experience using the AFA 1.7X on that particular lens, but my experience is that, in general, TC's (including the AFA 1.7X) don't work very well with most zooms, but do often work reasonably well with many primes (where they are always a compromise, of course).