On Mar 25, 2007, at 12:20 PM, Jack Davis wrote: > Anyone made at least a semi serious side-by-side DA 14 v DA 12-24(at > 14) image comparison? > Godfrey?
I recently looked at a couple of DA12-24 RAW demo files. There weren't any that were captures at exactly 14mm. My prior impressions that it is a good lens but has more CA and more rectilinear distortion than the DA14 does at lens openings and focal lengths which bracket the DA14 were borne out. The f/8 exposures were significant improvements over the f/4 exposures. But I don't own one so I can't do an exhaustive side-by-side unless someone wants to loan me one for testing. But those test shots inspired me to do some more exhaustive DA14 test shots on a variety of targets. My summary: - Some corner/edge light falloff is apparent until about f/5. - Rendering characteristics vary depending upon focus setting and lens opening, most are excellent particularly at f/4.5 and smaller lens openings if working in the very near range. - Corner and edge sharpness are satisfactory wide open but improve greatly when stopped down to f/5-5.6, after which they continue to improve a little but very slowly to f/11 or so. - Much after f/11, diffraction effects begin to intrude on sharpness. - Flare resistance is excellent even wide open. - There is a small amount of CA, consistent at all lens openings, which can be removed easily in Lightroom or Camera Raw. - It is a demanding lens to focus critically when wide open and focusing near the close-focus limits. At f/5.6 the DoF at normal shooting distances is so great that it covers a multitude of sins, but wide open and at close range you have to have it on the money. I go to manual focus and use Pentax Magnifier FB 2x for critical focus. - Using a tripod with this wide a lens is essential to getting the best resolution. Moving to the K10D, the incremental resolution upgrade is most advantageous for this lens and the DA21 Limited. I've had the DA14 since I first bought the DS body and it is one of my most consistent performers. I've made well over 3000 exposures with it. The more I use it, the more I learn to exploit it, the more I like it. Compared to the Sigma 14mm f/2.8 and Canon EF14/2.8L that I tested, the DA14 is a jewel and incredibly inexpensive for its quality. Regards field of view coverage, comparing what I get from it against my old work done with Nikkor 20mm f/3.5 AI-S, Zeiss Biogon 21/3.5, and Leica Elmarit-M 21/2.8 ASPH lenses, it holds its own very well. It's not quite up to what I could get from the Hasselblad 903SWC's Biogon 38mm f/4.5 ... but then very very few lenses in this class are. BTW: set to Program mode and the MTF line, the camera tends to keep it at f/5.6 most of the time, which is right in line with my evaluations which indicated best performance between f/4.5 and f/5.6. Godfrey -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
