pwithem

<p>I still don't see any logic supporting the premise that legacy full frame lenses will perform poorly on the K-1's 36MP sensor, as compared to 35mm film. I hear insinuation about coatings, which makes me think the sensor surface vs a film surface might register light a little bit differently, but I've never seen such a thing presented for judgment. Maybe there's something to this and it's been done somewhere? </p> <p>It makes sense that higher and higher pixel density would allow you to explore the limits of your glass in a way that film may not allow. That is, you could blow up a digital image more (effectively/easily) than you could film, and thereby expose evidence of glass imperfection. But if this is the case, it's only showing how digital would give you more capability over film, not that the glass performance is somehow worse. It's always up to the user how far you want to crop and zoom in a photo before printing, but if you operate on digital within similar boundaries you might use with film, I wouldn't expect any glass performance issues. </p> <p>Consider that the 16 MP K-5 has about half the sensor surface area and half the MP as the K-1 sensor, so the pixel density would be nearly the same as a K-5. I've been very happy with my full frame glass on the K-5, so why should I expect performance to get worse with the larger, uncropped sensor? (Of course, if it's vignetting, that would happen on 35mm film too.) Also consider that the K-5 has higher pixel density than the K20, K10, and *ist D. Those increases in density (even with noise) have been overall improvements, granting more crop/zoom capability. Was legacy full-frame glass getting worse for somebody during those body improvements? If you just want to make the same size prints as before at similar dpi, the K-1 36MP sensor is not going to limit you, it's just going to give you greater FOV.</p> <p>DPR's statement</p> <blockquote> <p>a 36MP sensor is <strong>likely to be fairly demanding</strong> on older glass, and our initial impressions of shooting with one older 50mm Pentax prime aren't wholly encouraging.</p> </blockquote> <p>doesn't prove anything; it doesn't tell us why a 36MP sensor is "likely to be demanding" on older glass. Maybe DPR knows something, but they're not telling us here. Until I see a direct comparison, the notion that higher MP "puts demands" on a lens is a boogey-man argument that many fear but few understand. </p> <p> </p>

<p>Sounds like SDM failure. I went through three failures and two repairs on my 16-50. After the third failure, I came very close to fixing, selling, and buying a Sigma lens. Instead, I did not send in for another repair, but found a procedure for altering the firmware, which made the lens default to use of screw drive motor for focus. It was the best thing I ever did. Of course, it makes the normal screw drive motor noise, but that was music to my ears because I knew it was focusing. <br> Giving up the SDM was a very easy sacrifice to make. In exchange, I got to keep weather sealing for the 16-50 range, retain the good optics of the 15-60, and not lose money on selling and buying new. And it simply works every time. <br> <br />You should be able to find the procedure by googling, but if you have trouble, I can take a look and try to confirm what I did - it was a couple of years back. I had to use my K10D (which I no longer have) to complete the procedure, so not sure if it'll work using current bodies.</p>