> From: Shel Belinkoff <[EMAIL PROTECTED]> > > Well, I found that on the ST 20/4,5 and the three examples of the K20/4.0 that > I had (still have one) the sharpness at the edges diminishes substantially, to > the point of a soft blur in some cases. I've made a lot of pics with those > lenses, and when the size gets up there, that soft blur becomes quite > noticeable. Unacceptable! Could I have had a total of FIVE poor examples? > Doubtful ...
Statistically, you could have had atypically bad samples (since the population must be in the thousands), especially of a lens that would be particularly sensitive to errors in manufacture, but I'd agree that it seems unlikely. I agree that the edges of the 20/4.5 SMC-T are bad, worse than any other 20mm I've tested. I would have expected the K20/4.0 to be better simply because I can't see much point in redesigning something so similar to the Takumar design if it wasn't better. Anybody know if the M20/4 is any better? Honestly, if the edges of the K lens are bad I fear the edges of the M are going to be worse. > Since I could get a fair sum for those lenses, I took the money and ran. The > K18/3.5 seems to be quite a bit better in that regard. Talk about a lens that is hard to find... Given what the more common 18/3.5 nikkors are going for, I don't think I'm in the market for an 18/3.5 Pentax. It's also going to be bigger than a 20mm if the nikkor is any guide, which makes it a less attractive choice for a light travel kit. > From: graywolf <[EMAIL PROTECTED]>, about poor sales of K/M 20/4.0 > A. They were not quite up to the quality of the more normal focal lengths. No > super-wide-angle was before computer design became the norm. Kinda forgot about computer-assisted design. It explains the poor performance of SMC-T 24 and 20 in terms of corner performance. > B. They were damn expensive (around $500, IIRC)compaired to their other lenses > (even the 35/2.0 and 85/2.0 were only around $300, I had them but could not > afford the 20mm). Remember we are talking 70's and 80's dollars here maybe 3-5x > todays in real money. And Pentax people didn't buy them? There seem to be a lot of 20/3.5 and even a couple of the coveted 20/4 AIS nikkors on the market. > C. Super-wide-angles were considered very specialized lenses, back then. 28's > were about the longest most folks thought of using, even 24mm's were considered > rathere specialized lenses. How then could Pentax justify Tak 20/4.5, K20/4, M20/4, K18/3.5, and SMC-T/K 15/3.5, all within a relatively short period of time? Nikon in more or less the same period of time had a 20/3.5 (big), 20/4.0, 20/3.5 (small), plus 18/4.0 and 18/3.5. Something was pushing the companies to put out a good ultrawide (although with the possible exception of the K18/3.5 none of the aforementioned lenses are really good from what I can tell). DJE
