Received DA* 16-50mm 2.8 from Pentax vs Tamron 17-50mm 2.8

Started Apr 11, 2014 | Discussions thread
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DAVID MANZE Veteran Member • Posts: 3,384
Received DA* 16-50mm 2.8 from Pentax vs Tamron 17-50mm 2.8

This morning I received the Pentax DA* 16-50mm 2.8 motor/circuit repaired FOC from Pentax. I set about checking and calibrating the lens for AF at about thirty meters, this is more of a task than I thought it was going to be, using F2.8 I checked three focal lengths, 16-28-50mm, first checks showed some decentering but not too bad, soft at the edges,sharp in the center with +5/6 AF adjustment, OK, then at F5.6 the images sharpened up but still not so hot really, then I checked AF accuracy to find it front focused. To cut a long story short, I ended up with zero adjustment to get the sharpest images I could at 5.6, this meant that at F2.8 the images were softer, this means as far as I can see that the lens suffers from spherical aberrations and the focus point changes as you stop down. Overall I was moderately disappointed with results still having some softness at 16mm at the edges.(5.6).

I hadn't noticed before but there's quite a bit of wobble in the double trombones when extended and I don't think the construction is anything special, in my view it's not up to professional standards, ( too much play), all in all an expensive but dated lens optically that does however benefit from AW sealing and a quiet AF that's has reasonable speed.

Next I brought out my trusty Tamron 17-50mm F2.8, well in short it trounced the DA* with ease being sharp at F2.8 @ 50mm ( just a hint of softening in the top left hand corner) and only the slightest softness at 17/28mm, it won against the Pentax hands down. The DA* flared a lot more with a white mast against set against a foliage backdrop ( purple glow) the Tammy showed hardly any.

The Tammy comes in at around 300-350 euros while the Pentax costs 900 euros. For me there's no contest the Tammy's the better lens and I think mechanically as good if not better if not a little more crudely made, but there's no AW and I mm less wide, the AF is a grind/ gerker. I prefer the latter I think the Pentax will go up for sale. Some may remember I bought it with a dead motor for 250 euros.

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The longer I have the Tammy the more I realize that's it's the best optical bargain out there today, (if you get a good one)

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