Originally posted by Docrwm Sorry, not convincing because Pentax does have some great lenses - just not the SDMs and this thread is about them and not Pentax overall. They're unreliable based on reports here at PF where folks are a wee bit bias in favor of Pentax.
My 2cents is that we have enough of a gap in hard data to prove conclusively that SDM is a dud RE: repair record but the anecdotal and survey evidence is compelling. I have stayed away from SDM so far but keep being tempted. I like what LensRentals said about 1. recent, 2. IS, 3. zooms are "an accident waiting to happen". I also like the further comment that Sigma wide zooms and primes are very reliable - wouldn't think that from the large sample data of the LensPlay report and comparatively high failure rates of the Sigmas (especially now, since Sigma has gone whole-hog for building in OS into every cotton picking zoom they redesign and a complete waste of money and weight for Pentax and Sony users). So, in comparison to others, and in comparison to the whole range of types of lenses on the market, SDM still feels like it is similar to the mechanical vagarities of a problematic design. Some may never fail, others may fail repeatedly. It seems to be a design issue similar to the complexity of what other manufacturers are experiencing (YES, a redesign of the motor is absolutely warranted, even mandated, based on staying competitive in an extreme marketplace). Again, I am drawing a summary of feelings I get when I read these reports, especially from experienced people like LensRentals and LensPlay. I might go for one SDM (50-135) and keep it at that, perhaps budget for an extended warranty plus a repair down the road. Maybe......or go for a Sigma or Tamron which have horrible record of decentering, sticking apertures, build quality, etc problems (or just keep my ca.1980's Tamron 19AH bought used for $85 and put up with the MF hassle). What fun!
Last edited by goldenarrow; 07-10-2012 at 07:19 PM.
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