Re: Frustrated With AF Problems
On Sun, Mar 23, 2008 at 12:24 AM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: On Mar 22, 2008, at 9:03 PM, Christine Aguila wrote: I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine Ya know, maybe Leica was right. They never put auto focus on their M or R cameras. When the focus is off, it's not their fault. And no one can complain about how fast the cameras focus either. Yes that may be true, but if i AF or MF some close up shots with the K10D and some lenses i have tried, it still looks focused in the finder, only to se it is not on screen So neither works for me.:-) Dave Godfrey -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
I understand your frustration, Joseph. But I think that even parfocal zoom lenses (as opposed to varifocal ones) don't focus the same at all focal lengths. Expecting them to be perfect, even the high end ones, is putting to much faith on technology. On the other hand, no AF system is perfect. AF can be convenient, and even faster than manual focus most of the time, but expecting it to be right on the money all the time is like thinking that auto exposure always leads to perfect results. So, if I were you, I wouldn't put much faith on the results of the lens-body calibration when they return from Pentax. Surely they will be able to achieve a better compromise than a user can do at home using focusing charts, but that's all. I think you should try Bill's suggestion, it seems to make sense and see if results are more consistent. Carlos -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
You don't have to do the focus tests. If you leave them all at zero, you have the same basic setup as the K10D. But the tests and adjustments can be helpful with some lenses. Paul On Mar 23, 2008, at 12:03 AM, Christine Aguila wrote: - Original Message - From: Paul Stenquist [EMAIL PROTECTED] I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
William Robb wrote: Joe, I think you ran the test backwards. Depth of field is not the issue, depth of focus is. As focal length extends, depth of field decreases, but depth of focus increases. Try calibrating your 50-135 at 50mm, and then see how it does at the long end. I am starting to think that my long time eschewing of zoom lenses may not be such a bad thing though. Not following, Bill. At 135 mm the lens definitely was improved by a -4 AF adjustment. So if testing at some other focal length gives a different result, I will have soft images at 135 mm. That doesn't necessarily follow. Bill's right. As he said, depth of focus increases at longer focal lengths. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
I don't test my zooms at every focal length. I tried that on the 12-24, and it drove me crazy. I set them to be right on at the lengths I use most of ten. The scale of focal point adjustment on the K20D is very fine. A bit of variation doesn't seem to be a problem in the real world of taking pictures. Paul On Mar 23, 2008, at 6:37 AM, Carlos Royo wrote: I understand your frustration, Joseph. But I think that even parfocal zoom lenses (as opposed to varifocal ones) don't focus the same at all focal lengths. Expecting them to be perfect, even the high end ones, is putting to much faith on technology. On the other hand, no AF system is perfect. AF can be convenient, and even faster than manual focus most of the time, but expecting it to be right on the money all the time is like thinking that auto exposure always leads to perfect results. So, if I were you, I wouldn't put much faith on the results of the lens-body calibration when they return from Pentax. Surely they will be able to achieve a better compromise than a user can do at home using focusing charts, but that's all. I think you should try Bill's suggestion, it seems to make sense and see if results are more consistent. Carlos -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Yesterday I ordered the K20D locally :-) Really looking forward to get to know this new tool, but I have also been having the same dilemma. I can see myself fiddling back and forth with the AF tuning facilities for ever. Just pixel peeping, instead of making photographs. I have a friend who has bought the camera, and he seem to be spending a way too much time thinking about focus accuracy. This said. You have my sympathy, Joe. AF problems are frustrating. But I'm not sure Nikon will solve your problems. If you hook at a Nikon forum, you will probably find others who experiences the same thing. I'm afraid QC is a term of the past. And we concumers looking for bang for the buck are the one who have forced it out of the window. MaritimTim 2008/3/23, Christine Aguila [EMAIL PROTECTED]: - Original Message - From: Paul Stenquist [EMAIL PROTECTED] I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Christine Aguila Subject: Re: Frustrated With AF Problems Yikes! I heard about the tilted sensor, but I just always assumed it was my poor technique. But I will say I'm getting a bit better. Still, maybe I should get this checked out. Thanks. Cheers, Christine Ansel Adams mentioned a fairly common visual syndrome that effectively keeps the person afflicted from holding a camera level. I don't recall more than that about it than that. To check to see if your sensor isn't level, put the camera on a tripod and level the head, either with the built in bubbles, or else put a trailer level (any decent auto parts store will have them) onto the hot shoe and level the camera. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
I am still wondering about sample variation. If different 50 mm lenses need different adjustments, then the factory couldn't really do it. Are folks making adjustments that are on a smaller scale then the errors in, let's say, the MZ-S? Steven Desjardins Department of Chemistry Washington and Lee University Lexington, VA 24450 (540) 458-8873 FAX: (540) 458-8878 [EMAIL PROTECTED] -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Ok, good to know this. Thanks, Paul. Cheers, Christine - Original Message - From: Paul Stenquist [EMAIL PROTECTED] To: Pentax-Discuss Mail List pdml@pdml.net Sent: Sunday, March 23, 2008 7:20 AM Subject: Re: Frustrated With AF Problems You don't have to do the focus tests. If you leave them all at zero, you have the same basic setup as the K10D. But the tests and adjustments can be helpful with some lenses. Paul On Mar 23, 2008, at 12:03 AM, Christine Aguila wrote: - Original Message - From: Paul Stenquist [EMAIL PROTECTED] I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Excellent! Thanks so much, William. I'll do it. Big thanks cheers, Christine - Original Message - From: William Robb [EMAIL PROTECTED] To: Pentax-Discuss Mail List pdml@pdml.net Sent: Sunday, March 23, 2008 10:41 AM Subject: Re: Frustrated With AF Problems Ansel Adams mentioned a fairly common visual syndrome that effectively keeps the person afflicted from holding a camera level. I don't recall more than that about it than that. To check to see if your sensor isn't level, put the camera on a tripod and level the head, either with the built in bubbles, or else put a trailer level (any decent auto parts store will have them) onto the hot shoe and level the camera. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
One step is a very small adjustment. Probably significantly smaller than the errors you would get just from the variation in flatness of film. Paul On Mar 23, 2008, at 12:01 PM, Steve Desjardins wrote: I am still wondering about sample variation. If different 50 mm lenses need different adjustments, then the factory couldn't really do it. Are folks making adjustments that are on a smaller scale then the errors in, let's say, the MZ-S? Steven Desjardins Department of Chemistry Washington and Lee University Lexington, VA 24450 (540) 458-8873 FAX: (540) 458-8878 [EMAIL PROTECTED] -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
On Sun, Mar 23, 2008 at 11:41 AM, William Robb [EMAIL PROTECTED] wrote: Ansel Adams mentioned a fairly common visual syndrome that effectively keeps the person afflicted from holding a camera level. I don't recall more than that about it than that. To check to see if your sensor isn't level, put the camera on a tripod and level the head, either with the built in bubbles, or else put a trailer level (any decent auto parts store will have them) onto the hot shoe and level the camera. I have a hell of a time keeping my panned flat photos in the horse ring level. Thank god for PS and rotate.:-) Dave William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) G On Mar 23, 2008, at 5:29 AM, Paul Stenquist wrote: I don't test my zooms at every focal length ... -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Frustrated With AF Problems--Update
Just to refresh everyone's memory: My defective DA* 16-50 is ready to go to Pentax to correct the fact that it won't autofocus to infinity at 16 mm on the K20D. The K20D has to go with it. Before sending them off I thought I would check the focus asjustment of the DA* 50-135. I tested it at 135 mm, figuring that the most rigorous test would be at that focal length because that's where the depth of field is smallest. It turns out that an adjustment of -4 gives the sharpest distance focus at that focal length. But then I noticed that when I zoom the lens to 50 mm it now autofocuses beyond infinity, and the images are not sharp. Arghhh! Okay, I guess the DA* 50-135 has to go to Pentax too to be calibrated to the K20D. But this is disturbing and frustrating. I have been concerned that it may be difficult or impossible to adjust the AF of zoom lenses through the K20D--adjusting for correct focus at one focal length could mean incorrect focus elsewhere. What I have seen so far (with both DA* lenses) confirms that suspicion. Joe, I think you ran the test backwards. Depth of field is not the issue, depth of focus is. As focal length extends, depth of field decreases, but depth of focus increases. Try calibrating your 50-135 at 50mm, and then see how it does at the long end. I am starting to think that my long time eschewing of zoom lenses may not be such a bad thing though. William Robb - Can someone please explain to me why depth of focus increases at longer focal lengths? Anyway, I tested the lens again this morning at 50mm, running from -2 to +2 AF adjustments. If there are any differences, they are exceedingly small. At 200% magnification I have to conclude that at 50 mm the lens performs best at 0 focus adjustment. But this still leaves the lens misfocusing at 135 mm. If I correct for that it misfocuses at 50 mm. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
But its worth doing a quick test with the K20D. I never tested a lens prior to shooting with that camera. But I was able to make a valuable correction for at least one of my lenses -- the FA 50/1.4. On Mar 23, 2008, at 1:21 PM, Godfrey DiGiorgi wrote: I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) G On Mar 23, 2008, at 5:29 AM, Paul Stenquist wrote: I don't test my zooms at every focal length ... -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Yes, but, if it looks focused, but it actually is not, Dave On Sun, Mar 23, 2008 at 1:21 PM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) G On Mar 23, 2008, at 5:29 AM, Paul Stenquist wrote: I don't test my zooms at every focal length ... -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
On Sun, Mar 23, 2008 at 9:21 AM, Tim Øsleby [EMAIL PROTECTED] wrote: Yesterday I ordered the K20D locally :-) Really looking forward to get to know this new tool, but I have also been having the same dilemma. I can see myself fiddling back and forth with the AF tuning facilities for ever. Just pixel peeping, instead of making photographs. I have a friend who has bought the camera, and he seem to be spending a way too much time thinking about focus accuracy. This said. You have my sympathy, Joe. AF problems are frustrating. But I'm not sure Nikon will solve your problems. If you hook at a Nikon forum, you will probably find others who experiences the same thing. I'm afraid QC is a term of the past. And we concumers looking for bang for the buck are the one who have forced it out of the window. MaritimTim Nikon users are having just as many problems with AF accuracy, particularly on the lower-end bodies in the same market as the K10D/K20D. The D3/D300 have the same sort of AF fine-tune as the K20D for this reason. I'm beginning to think that digital is just more sensitive to Depth of Focus than film is. -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Any SLR which behaves like this is broken. Have it fixed. G On Mar 23, 2008, at 11:48 AM, David J Brooks wrote: Yes, but, if it looks focused, but it actually is not, On Sun, Mar 23, 2008 at 1:21 PM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
David J Brooks wrote: On Sun, Mar 23, 2008 at 1:21 PM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) Yes, but, if it looks focused, but it actually is not, Then there's an issue with the focusing screen or mirror alignment, not the autofocus system. Needs to be repaired. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Its gone back to Pentax Canada. Just waiting now. Dave On Sun, Mar 23, 2008 at 3:08 PM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: Any SLR which behaves like this is broken. Have it fixed. G On Mar 23, 2008, at 11:48 AM, David J Brooks wrote: Yes, but, if it looks focused, but it actually is not, On Sun, Mar 23, 2008 at 1:21 PM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
On Sun, Mar 23, 2008 at 3:16 PM, Mark Roberts [EMAIL PROTECTED] wrote: David J Brooks wrote: On Sun, Mar 23, 2008 at 1:21 PM, Godfrey DiGiorgi [EMAIL PROTECTED] wrote: I don't test mine at all. I just let the camera focus them, and correct it when the focus isn't what I want. That's what the focusing ring is for... Saves a lot of angst and time. :-) Yes, but, if it looks focused, but it actually is not, Then there's an issue with the focusing screen or mirror alignment, not the autofocus system. Needs to be repaired. I'll call them Monday and leave a message for Maria if they are off for the easter Monday. That is my main plroblem with the close up focus from F 4 to F2.8 or bigger. It looks fine in the finder. Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Equine Photography www.caughtinmotion.com http://brooksinthecountry.blogspot.com/ Ontario Canada -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Frustrated With AF Problems
My defective DA* 16-50 is ready to go to Pentax to correct the fact that it won't autofocus to infinity at 16 mm on the K20D. The K20D has to go with it. Before sending them off I thought I would check the focus asjustment of the DA* 50-135. I tested it at 135 mm, figuring that the most rigorous test would be at that focal length because that's where the depth of field is smallest. It turns out that an adjustment of -4 gives the sharpest distance focus at that focal length. But then I noticed that when I zoom the lens to 50 mm it now autofocuses beyond infinity, and the images are not sharp. Arghhh! Okay, I guess the DA* 50-135 has to go to Pentax too to be calibrated to the K20D. But this is disturbing and frustrating. I have been concerned that it may be difficult or impossible to adjust the AF of zoom lenses through the K20D--adjusting for correct focus at one focal length could mean incorrect focus elsewhere. What I have seen so far (with both DA* lenses) confirms that suspicion. But there are larger implications: 1. Does this mean that I have to give up using autofocus zoom lenses if their focus cannot be uniformly adjusted? 2. Does this mean that every time I buy a new camera I have to send the body and all of my zoom lenses to Pentax to be calibrated to each other? 3. Does this mean that every time I buy a new zoom lens I have to send it and all bodies currently in use to Pentax? Or did I just get three bad DA* lenses (this is my second DA* 50-135) and two bad K20D bodies? That's about $3000 worth of gear that I can't use. (Yes, I know, some of you will want to reply that your zoom lenses work fine. Please don't.) Frustrated, frustrated, frustrated. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Joseph Tainter Subject: Frustrated With AF Problems My defective DA* 16-50 is ready to go to Pentax to correct the fact that it won't autofocus to infinity at 16 mm on the K20D. The K20D has to go with it. Before sending them off I thought I would check the focus asjustment of the DA* 50-135. I tested it at 135 mm, figuring that the most rigorous test would be at that focal length because that's where the depth of field is smallest. It turns out that an adjustment of -4 gives the sharpest distance focus at that focal length. But then I noticed that when I zoom the lens to 50 mm it now autofocuses beyond infinity, and the images are not sharp. Arghhh! Okay, I guess the DA* 50-135 has to go to Pentax too to be calibrated to the K20D. But this is disturbing and frustrating. I have been concerned that it may be difficult or impossible to adjust the AF of zoom lenses through the K20D--adjusting for correct focus at one focal length could mean incorrect focus elsewhere. What I have seen so far (with both DA* lenses) confirms that suspicion. Joe, I think you ran the test backwards. Depth of field is not the issue, depth of focus is. As focal length extends, depth of field decreases, but depth of focus increases. Try calibrating your 50-135 at 50mm, and then see how it does at the long end. I am starting to think that my long time eschewing of zoom lenses may not be such a bad thing though. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Joe, I think you ran the test backwards. Depth of field is not the issue, depth of focus is. As focal length extends, depth of field decreases, but depth of focus increases. Try calibrating your 50-135 at 50mm, and then see how it does at the long end. I am starting to think that my long time eschewing of zoom lenses may not be such a bad thing though. William Robb - Not following, Bill. At 135 mm the lens definitely was improved by a -4 AF adjustment. So if testing at some other focal length gives a different result, I will have soft images at 135 mm. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Joe. I'm nipping a smooth VSOP here, so my I don't trust my own judgement 100%. But I just had a read up at Depht of of Focus and Depht f Field at Wikipedia. And it seems that Bills advise could be worth lisening to here. No harm in trying a different approach, is it? Judging from my read up, he may have a point. (He may have two points, but I don't like the last one, so lets pretend we did not read that one ;-) ) MaritimTim 2008/3/23, Joseph Tainter [EMAIL PROTECTED]: Joe, I think you ran the test backwards. Depth of field is not the issue, depth of focus is. As focal length extends, depth of field decreases, but depth of focus increases. Try calibrating your 50-135 at 50mm, and then see how it does at the long end. I am starting to think that my long time eschewing of zoom lenses may not be such a bad thing though. William Robb - Not following, Bill. At 135 mm the lens definitely was improved by a -4 AF adjustment. So if testing at some other focal length gives a different result, I will have soft images at 135 mm. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Joe. I'm nipping a smooth VSOP here, so my I don't trust my own judgement 100%. But I just had a read up at Depht of of Focus and Depht f Field at Wikipedia. And it seems that Bills advise could be worth lisening to here. No harm in trying a different approach, is it? Judging from my read up, he may have a point. - Thanks for the comment, Tim. But I think I will just send the lens to Pentax. Then if that is not satisfactory it may finally be time to look into switching to Nikon. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
On Sun, Mar 23, 2008 at 10:18 AM, Tim Øsleby [EMAIL PROTECTED] wrote: Joe. I'm nipping a smooth VSOP here, so my I don't trust my own judgement 100%. But I just had a read up at Depht of of Focus and Depht f Field at Wikipedia. And it seems that Bills advise could be worth lisening to here. No harm in trying a different approach, is it? Judging from my read up, he may have a point. (He may have two points, but I don't like the last one, so lets pretend we did not read that one ;-) ) LOL MARK! Cheers, Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
I think it means that you are testing too much and not taking enough pics. I also think that your problems may be a symptom of having to be first on the block. My DA* 50-135 focuses perfectly with my K20D at both 50mm and 135mm. I did adjust it. I think the number was -1 or thereabouts. Paul On Mar 22, 2008, at 8:32 PM, Joseph Tainter wrote: My defective DA* 16-50 is ready to go to Pentax to correct the fact that it won't autofocus to infinity at 16 mm on the K20D. The K20D has to go with it. Before sending them off I thought I would check the focus asjustment of the DA* 50-135. I tested it at 135 mm, figuring that the most rigorous test would be at that focal length because that's where the depth of field is smallest. It turns out that an adjustment of -4 gives the sharpest distance focus at that focal length. But then I noticed that when I zoom the lens to 50 mm it now autofocuses beyond infinity, and the images are not sharp. Arghhh! Okay, I guess the DA* 50-135 has to go to Pentax too to be calibrated to the K20D. But this is disturbing and frustrating. I have been concerned that it may be difficult or impossible to adjust the AF of zoom lenses through the K20D--adjusting for correct focus at one focal length could mean incorrect focus elsewhere. What I have seen so far (with both DA* lenses) confirms that suspicion. But there are larger implications: 1. Does this mean that I have to give up using autofocus zoom lenses if their focus cannot be uniformly adjusted? 2. Does this mean that every time I buy a new camera I have to send the body and all of my zoom lenses to Pentax to be calibrated to each other? 3. Does this mean that every time I buy a new zoom lens I have to send it and all bodies currently in use to Pentax? Or did I just get three bad DA* lenses (this is my second DA* 50-135) and two bad K20D bodies? That's about $3000 worth of gear that I can't use. (Yes, I know, some of you will want to reply that your zoom lenses work fine. Please don't.) Frustrated, frustrated, frustrated. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Tim Øsleby Subject: Re: Frustrated With AF Problems Joe. I'm nipping a smooth VSOP here, My dad always said that was short for Very Special Old Poop William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Joseph Tainter Subject: Re: Frustrated With AF Problems Joe, I think you ran the test backwards. Depth of field is not the issue, depth of focus is. As focal length extends, depth of field decreases, but depth of focus increases. Try calibrating your 50-135 at 50mm, and then see how it does at the long end. I am starting to think that my long time eschewing of zoom lenses may not be such a bad thing though. William Robb - Not following, Bill. At 135 mm the lens definitely was improved by a -4 AF adjustment. So if testing at some other focal length gives a different result, I will have soft images at 135 mm. That doesn't necessarily follow. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Paul Stenquist Subject: Re: Frustrated With AF Problems I think it means that you are testing too much and not taking enough pics. I also think that your problems may be a symptom of having to be first on the block. My DA* 50-135 focuses perfectly with my K20D at both 50mm and 135mm. I did adjust it. I think the number was -1 or thereabouts. It's too bad though that one can't buy a new product and have it work right. Pentax has been making AF systems and zoom lenses for long enough that a buyer shouldn't have to be worried about buying an early release product. This seems to be a bit systemic, in that a number of K10 owners (myself included) reported focusing errors also. My 31mm lens went from being an excellent lens on my film cameras to an OK lens on my istD to a dissapointingly bad lens on my K10. Fortunately, that hack got reported and I was able to bring the camera into acceptable performance fairly easily. Having said that, I really think Joe should humour us and retest his lens at the short focal length and see if his pictures aren't acceptable at the long end. Note, I am saying pictures, not test charts. I believe I intimated in a previous post that all the adjustments they put into this camera would probably cause some grief, as a certain amount of measurebating is unavoidable when one can play with tweaking settings, and I would question their judgement about putting settings like this onto a camera but for the fact users from every camera maker are having similar problems. I appreciate that Pentax is selling pretty good bang for the buck, but I would happily pay a premium for equipment that had actually passed quality control rather than just packed in styrofoam and shipped to the dealer. When I was using Nikon, I was told by a rep that a significant part of the cost of an F2 was making certain that little things like ensuring the 100% viewfinder shipped with the body was actually aligned so that what you saw really was what you got, that the mirror and screen was aligned so that the optical distance between the rear nodal point of the lens and the screen and film plane was identical, and that the exposure system was accurate. Pentax really seems to be having problems sending out collimated optical gear, and if they hope to keep selling equipment they need to pull up their socks and fix their QC problems. William Robb -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Having said that, I really think Joe should humour us and retest his lens at the short focal length and see if his pictures aren't acceptable at the long end. Okay, I'll see how I feel in the morning. I don't follow the reasoning about the short focal length, but I'm sure there are still things for me to learn. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
It will at least be informative. By the way, I apologize for being glib in regard to this. My DA 12-25 varies greatly from one end to the next. But it still takes nice pics. I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. Paul On Mar 22, 2008, at 11:32 PM, Joseph Tainter wrote: Having said that, I really think Joe should humour us and retest his lens at the short focal length and see if his pictures aren't acceptable at the long end. Okay, I'll see how I feel in the morning. I don't follow the reasoning about the short focal length, but I'm sure there are still things for me to learn. Joe -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Paul Stenquist [EMAIL PROTECTED] I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
On Sun, Mar 23, 2008 at 1:03 PM, Christine Aguila [EMAIL PROTECTED] wrote: - Original Message - From: Paul Stenquist [EMAIL PROTECTED] I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine I haven't tested a single lens on the K20D Compared to my K10D I'm loving the fact that the K20D actually focuses accurately. I had no faith at all in the K10D's AF focus confirmation. Given my poor eyesight that was a big problem. Cheers, Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Dave: What focusing screen do you/did you on K20D K10D? My eye sight has really gotten bad my shots off-camera tend to tilt to the right. I was thinking maybe the scale matte focusing screen. What do you think? Might that screen help matters a bit? Cheers, Christine - Original Message - From: David Savage [EMAIL PROTECTED] To: Pentax-Discuss Mail List pdml@pdml.net Sent: Saturday, March 22, 2008 11:08 PM Subject: Re: Frustrated With AF Problems On Sun, Mar 23, 2008 at 1:03 PM, Christine Aguila [EMAIL PROTECTED] wrote: - Original Message - From: Paul Stenquist [EMAIL PROTECTED] I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine I haven't tested a single lens on the K20D Compared to my K10D I'm loving the fact that the K20D actually focuses accurately. I had no faith at all in the K10D's AF focus confirmation. Given my poor eyesight that was a big problem. Cheers, Dave -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
On Mar 22, 2008, at 9:03 PM, Christine Aguila wrote: I'm not sure that this new focus test capabiliyt is really a blessing. It may be a curse. After seeing what the K20D does with high ISOs plus all the other new features, I have to admit I desire this camera--but having read all the stuff about the focus test capability, I'm a little nervous about that. My head is spinning! I'd have to learn how to do focus tests, which I'm sure I could do, but maybe down the line. Cheers, Christine Ya know, maybe Leica was right. They never put auto focus on their M or R cameras. When the focus is off, it's not their fault. And no one can complain about how fast the cameras focus either. Godfrey -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
G'day Christine Just the supplied focus screen. I have a natural tenancy to slope my shots too, but if I remember to pay attention I can get it level :-) Also you maybe one of the unlucky ones that have tilted sensor :-/ Cheers, Dave On Sun, Mar 23, 2008 at 1:21 PM, Christine Aguila [EMAIL PROTECTED] wrote: Dave: What focusing screen do you/did you on K20D K10D? My eye sight has really gotten bad my shots off-camera tend to tilt to the right. I was thinking maybe the scale matte focusing screen. What do you think? Might that screen help matters a bit? Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
Yikes! I heard about the tilted sensor, but I just always assumed it was my poor technique. But I will say I'm getting a bit better. Still, maybe I should get this checked out. Thanks. Cheers, Christine - Original Message - From: David Savage [EMAIL PROTECTED] To: Pentax-Discuss Mail List pdml@pdml.net Sent: Saturday, March 22, 2008 11:31 PM Subject: Re: Frustrated With AF Problems G'day Christine Just the supplied focus screen. I have a natural tenancy to slope my shots too, but if I remember to pay attention I can get it level :-) Also you maybe one of the unlucky ones that have tilted sensor :-/ Cheers, Dave On Sun, Mar 23, 2008 at 1:21 PM, Christine Aguila [EMAIL PROTECTED] wrote: Dave: What focusing screen do you/did you on K20D K10D? My eye sight has really gotten bad my shots off-camera tend to tilt to the right. I was thinking maybe the scale matte focusing screen. What do you think? Might that screen help matters a bit? Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: Frustrated With AF Problems
- Original Message - From: Godfrey DiGiorgi [EMAIL PROTECTED] Ya know, maybe Leica was right. They never put auto focus on their M or R cameras. When the focus is off, it's not their fault. And no one can complain about how fast the cameras focus either. Godfrey Ya know, point taken. Maybe it's time I shore up my manual focusing skills. Cheers, Christine -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
