On 2 September 2010 23:19, John Celio <n...@neovenator.com> wrote: > You don't understand. My camera backfocuses like it was *meant* to do that, > even after sending it back to Pentax twice (both times for other problems, > but I asked them to fix this, too). The image will look sharp in the > viewfinder, but when looking at the photo on my computer later it becomes > apparent that, even though the focus locked on a particular subject (say, a > person standing six feet from me), the sharpest part of the photo is just > behind them. Something is misaligned, and Pentax/CRIS hasn't bothered to > fix it, even though their repair papers said they did. > > When I'm focusing manually, I will sometimes take a few extra photos with > what I see in the viewfinder slightly out of focus, hoping I'll find the > sweet spot somewhere. > > I swear, if I didn't have so much Pentax junk here, I'd go buy a Nikon. > > John > Stuck Being a Disgruntled Pentaxian
I feel for you, John, as I've has similar problems. I'm going to outline a procedure below so you can figure out exactly what the problem is. First you need to print out a focus chart (well, you don't *have* to, but it makes things a bit easier; if you don't use a chart, focus on something continuous, like a floor, that will allow you to clearly see back/front focus). I like Yvon Bourque's: http://www.k10dbook.com/newchart.pdf 1) Set you camera on a tripod and focus manually on the center point in the chart (or whatever it is you've decided to use in place of a chart), which I'll refer to as "subject" with the center of your VF over it. 2) Take a photograph. 3) Rotate your focus ring to infinity, turn AF on and autofocus (without moving the camera) using the central AF sensor (this is why in point 1 you had to place your subject in the center of the VF). 4) Take a photograph. 5) Rotate your focus ring to the lens's closest focusing distance, then autofocus on the subject again. 6) Take a photograph. Now comes the annoying part: Repeat the above with a couple other lenses so you have at least 3 to compare results between allowing you to rule out the lens as the problem. When you review the images on your computer (you should have a set of 3 for each lens), there are 3 possible outcomes: Outcome 1: The manually focused image is in focus but the autofocused ones are back/front focused. Outcome 2: The manually focused image is back/front focused but the autofocused ones are in focus. Outcome 3: All are back/front focused, although the manual ones could be front and the AF one back, or viceversa. Ideally you would want Outcome 4: All photos are in focus. Depending on the outcome from the list above, and assuming results are consistent across lenses, these are your camera problems: Problem 1: The AF sensor is miscalibrated. This is what the micro adjust feature on the K20D and K-7 is useful for. It's an easy fix for a tech, and maybe you could do it yourself with the K10D debug program. Problem 2: The mirror is misaligned but a lazy tech simply adjusted the AF sensor to compensate for it. You need a tech to service your camera. Problem 3: The mirror is misaligned and the AF sensor is not calibrated to compensate for the offset mirror. You need a tech to service your camera. Hope this helped. Cheers, --M. -- \/\/o/\/\ --> http://WorldOfMiserere.com http://EnticingTheLight.com A Quest for Photographic Enlightenment -- 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.
