david_kelly13 Posted May 13, 2007 Share Posted May 13, 2007 Earlier this year Carl Weese reported in The Online Photographer that the K10D had a problem focusing the DA21mm f3.2 on narrow vertical objects. He had Pentax send him a second lens to make sure it wasn't just a QC matter, and his tentative conclusion was that the AF sensor was much broader than indicated in the viewfinder, and therefore might sometimes favor a contrasty background object. He wrote that the problem didn't occur with the 40 or 70mm DA's, just the 21. I"m about to buy a K10D and would like to make the DA21 my first lens for it. Has Pentax addressed the problem Weese identified (and several other users confirmed)? I can't fall back on manual focusing because my left hand is impaired -David Kelly Link to comment Share on other sites More sharing options...
neil_swanson Posted May 13, 2007 Share Posted May 13, 2007 Only a few moments ago I got a return auth# from B&H for the exchange of my new DA21 for another. It just isn't sharp. I know about the AF problems. I've tried MF'ing the lens but I just can't focus like I used to plus often what you are focusing on is very small anyway. I di some tests at 3.2-8 and it was soft (well not biting sharp) until F8. At that point maybe DOF covered the fault. I need this lens to be as good as possible wide open. I know it is no ultra super sharp WO lens but it really has to be better than mine sems to be. BTW a Nikon D2 series camera can and will also be fooled by something high in contrast right near where you want to focus. I may be expecting mroe than the lens can deliver. I am comparing it to the 43,50 and 77. It isn't close to any of those. Link to comment Share on other sites More sharing options...
michael_kuhne Posted May 13, 2007 Share Posted May 13, 2007 I have not done any scrutinizing tests at smaller apertures, etc. but I have not yet noticed a problem with the 21mm on my K100D. I often do prefer to shoot with center-only AF sensor for accurate focus. Link to comment Share on other sites More sharing options...
neil_swanson Posted May 14, 2007 Share Posted May 14, 2007 I never let the camera choose a focus point. I have the camera always set to let me put it where I want it. The camera does have 9 cross type focus sensors afterall so the center one isn't the only "good" one like many other cameras. But center sensor or not ISO 100, 5 ft away from a near frame filling texture filled piece of wood in good light and a shutter speed over 1/1000 and the image isn't sharp? I did the same test with a $100 28mm A-SMC MF lens and it is far better than this 21 I have. I hope the exchange lens is better. I need this length and I don't want a zoom to get it. Link to comment Share on other sites More sharing options...
david_kelly13 Posted May 14, 2007 Author Share Posted May 14, 2007 Neil, you have hijacked this thread to discuss quite another issue, but as long as you have: if there is a QC problem with the lens you'll find out right away and please let us know. This lens is not the only reason I want a K10D but it is a big one. I'm experiencing Nikon withdrawal symptoms as i realize i can't simply go to KEH.com and grab an EX grade 20mm f2.8 for 300 bucks anymore. Link to comment Share on other sites More sharing options...
david_kelly13 Posted May 14, 2007 Author Share Posted May 14, 2007 Michael: Different camera, different firmware. If it works all the time with the K100D then it will probably turn out to be a firmware issue with the K10D. At least I hope so. Link to comment Share on other sites More sharing options...
neil_swanson Posted May 14, 2007 Share Posted May 14, 2007 David sorry you feel I took the point of your thread away. I just wanted to add that while I had read of Carls focus problems and also of others that I had what mught just be a bum lens. I though my post might prove timely. i did the tests I did to rule out the focus sensor just plain missing my target. Now I hope the lens was just a bad copy. I really like the view and the size. I also have a Nikon system. I have seen and now know when teh af sensor will be fooled and miss focus and I'd say that yes the Pentax could do the same thing. I will report back on wether or nor 21 #2 is the same or better than the one I have. Link to comment Share on other sites More sharing options...
john carter Posted May 18, 2007 Share Posted May 18, 2007 Has anyone had a 'major' focusing (or sharpness) problem with a FA 20mm f2.8? I haven't. Link to comment Share on other sites More sharing options...
david_kelly13 Posted May 18, 2007 Author Share Posted May 18, 2007 Neil, i'm glad you are following up on the lens -don't mind being hijacked at all! As for the 20mm 2.8 focusing perfectly, glad to hear it but again, this isn't the Nikon world where good used ones abound at KEH, I'd have to buy new=expensive :( Link to comment Share on other sites More sharing options...
john carter Posted May 20, 2007 Share Posted May 20, 2007 I agree (money), I did pay 'full wack' for my 20mm FA f2.8 a little over a year ago. I have to tell you, it was worth it. I just (8 months ago) got a 35 FA f2.0 for my K10d, and it is the only lens that has ever been on it, again no problems. I use, like someone said here or maybe someplace else, the single spot meter AF mode. Link to comment Share on other sites More sharing options...
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