Originally posted by augustmoon On a whim, on my trip back to see if I could swap out my 3rd copy of the Tamron 17-50 for perhaps a 4th copy, They unboxed and I snapped on the Pentax 16-50, nice, very nice, I thought to my self and bought it. Wow, now I know that I had 3 Tamron 17-50 copies in a row that performed poorly for me, but the Pentax 16-50 I bought was sharper at all FL and at 2.8 both center and corner.
Now this lens does have a curved field of focus, so I know a lot of people like to buy this lens (perhaps other lenses?) to photograph newspapers and brick walls, especially at 16mm and at 2.8. ( I think that most of the images posted of newspapers and brick walls are actually with this particular lens...)
I would say that this is not a good newspaper or brick wall lens.
Glad you manage what I was not able to - a good copy of the DA* 16-50mm.
I took my share of brick walls and newspaper photos, as well as a variety of landscapes and trees. Going in, I was well aware of the significantly poorer edge/border IQ of the DA* lens, and in fact the left half behaved overall in line with my expectations. The left edge had poorer IQ than the center, but as the lens was stopped down and/or the f.l. increased from 16mm, the amount of the poorer IQ at the left edge decreased to a narrorer band.
However, the right 25% of the image never cleared up. Increasing the f.l. had a negligible effect on the outer half of the right side. While stopping the lens down did reduce the amount of blur/unsharpness some on the right, it never decreased the actual area/extent of the blur - reducing the band of the blur to a narrorer boarder to the right (as was the case on the left side). So, for instance, if I shot a portrait with the right side up, the person's face was never really sharp (even stopped down and at 35mm or 50mm). However, it I took a portrait with the left side up, then the person's face was sharp.
I just wanted to make sure that I had at least a decent quality copy of the lens and then go out and enjoy taking photos, not perform QC for Pentax. What the brick walls, newspaper, and tree/leave images proved (to me) was that consistently across 3 lenses that the right side severely under-performed compared to the left side.
Fool me once - shame on you. Fool me twice - shame on me. The third time's a charm - not this time. So a 4th try was out of the question. I'm not in or by NYC where I can spend a day, go thru boxes, and keep trying to find a good DA* 16-50mm. I just want a good quality lens that I can rely on.