goodly out of focus:-). When trying to detect spots on the sensor, you want only a white surface in front of the lens. Focusing on the surface is counterproductive in that you pick up more of its texture.
Paul On Dec 6, 2010, at 5:00 PM, Jack Davis wrote: > Badly OOF? > > Jack > > --- On Mon, 12/6/10, P N Stenquist <[email protected]> wrote: > >> From: P N Stenquist <[email protected]> >> Subject: Re: Latest Pentax Scare: Blobs on K-5 Sensor >> To: "Pentax-Discuss Mail List" <[email protected]> >> Date: Monday, December 6, 2010, 1:52 PM >> >> On Dec 6, 2010, at 4:36 PM, Miserere wrote: >> >>> On 6 December 2010 16:31, P N Stenquist <[email protected]> >> wrote: >>>> >>>> On Dec 6, 2010, at 4:16 PM, Miserere wrote: >>>> >>>>> On 6 December 2010 16:03, paul stenquist >> <[email protected]> >> wrote: >>>>>> >>>>>> On Dec 6, 2010, at 3:33 PM, Charles >> Robinson wrote: >>>>>> >>>>>>> On Dec 6, 2010, at 14:19, Miserere >> wrote: >>>>>>> >>>>>>>> Any of you guys with a K-5 >> experiencing any of this? >>>>>>>> >>>>>>>> http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=37092371 >>>>>>>> >>>>>>>> http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=37101106 >>>>>>>> >>>>>>>> Maybe you K-7 owners could take a >> look too. No need to transfer test >>>>>>>> images to the computer, the blobs >> can be seen on the LCD. >>>>>>>> >>>>>>> >>>>>>> Frankly, if the images turn out OK >> (besides being all green) then there is no problem. >> Interesting as a curiosity, but not in a "OMG the sky is >> falling" kind of way. >>>>>>> >>>>>>> Seriously... why would a person even >> bother looking for something like this unless it's affecting >> the output? >>>>>>> >>>>>>> And by "affect the output" I mean: can >> this really be SEEN on something other than an f/22 shot of >> a blank grey surface? >>>>>> >>>>>> It could be seen on any number of small >> aperture shots. I'm definitely going to test for it. >>>>>> Paul >>>>> >>>>> Thanks for the replies so far, and please keep >> 'em coming. >>>>> >>>>> My test unit has a string of blobs near the >> center (most people seem >>>>> to report them "near the center" for what it's >> worth). They are >>>>> noticeable at f/8 and smaller when >> photographing a blank surface; I >>>>> suspect in real photographs (with plenty of >> detail) they should >>>>> *maybe* be noticeable at f/11 and onwards. I >> rarely photograph at such >>>>> apertures, but I can imagine people shooting >> landscapes would be >>>>> annoyed to find these blobs in their blue >> skies. Then again, a blob in >>>>> a blue sky is easy to clone out. Then again, >> again, we'd all prefer >>>>> not to have to clone out blobs as part of our >> postprocessing. >>>>> >>>>> >>>> >>>> I just tested my camera in the same manner as the >> guy reported on dpreview. I filled my computer screen with >> white and shot it with my DA* 16-50 at about 30mm, F stops >> were f22, f16 and f11. Focus set to infinity. No blobs. Saw >> a few specs of dust, Did the sensor clean operation and >> retested, and the dust was gone. I get pure white. >>>> Paul >>> >>> That's good news, Paul. >>> >>> For what it's worth, my blobs are much better defined >> using the sky or >>> a blank piece of paper than the computer screen. Not >> sure why anyone >>> would want advice on improving their blob definition, >> but it's one of >>> the many useful services I provide to the community. >>> >>> Because giving back is important. >>> >> I repeated the test with white paper. Still no blobs at >> f22. Just out of focus paper. >> Paul >>> >>> —M. >>> >>> \/\/o/\/\ --> http://WorldOfMiserere.com >>> >>> http://EnticingTheLight.com >>> A Quest for Photographic Enlightenment >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> [email protected] >>> 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 >> [email protected] >> 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 > [email protected] > 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 [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
