It almost certainly isn't under the filter. It's simple dust on you sensor.
Get a Rocket Blower or something similar (DO NOT use canned air) and blow off the sensor. Do that 2 or 3 times, and if it doesn't go away, I use a sensor pen. If that doesn't get rid of it, then move to wet cleaning using swabs and fluid. Don't be surprised if you have to repeat a couple times. The biggest thing is not to panic about it. You can always clone out the spot if needed until you can clean the sensor. You will only see it when you have the lens stopped down, and it is in an area of even tonality without a lot a detail (sky, snow, light colored walls, etc). On Fri, Jun 11, 2010 at 9:23 AM, Bob Sullivan <rf.sulli...@gmail.com> wrote: > Rob, > I've tried the dust detect function and it shows nothing - a white > screen mock-up of the sensor. > I'm afraid of something beneath the filter assembly and the trouble of > replacing the camera. > Thanks for the suggestions as to cause. > Regards, Bob S. > > > On Fri, Jun 11, 2010 at 12:26 AM, Rob Studdert <distudio.p...@gmail.com> > wrote: >> On 11/06/2010, Bob Sullivan <rf.sulli...@gmail.com> wrote: >> >>> I cannot see anything on the sensor's surface. >>> Furthermore, the spot disappears when I open the lens to f2.8 or f4.0. >>> Spot happens with multiple lenses at f16 or f22. >>> It's a small spot, but I don't understand the mechanics. >>> Is my sensor broken? >> >> Hi Bob, >> >> What you're describing sounds to me like a classic case of >> contaminants on the surface of the sensor assembly. Stopping down will >> make the problem more visible, this is what the dust detect >> effectively does, have you tried that function yet? It's often almost >> impossible to see dust specs with the naked eye but if the problem >> persists then I'd assume it's still there. Hopefully it's on the top >> surface not sandwiched between the filter assembly in front of the >> actual sensor, in the later case I'd get the camera replaced, only a >> thorough clean and testing will tell. >> >> Cheers, >> >> -- >> Rob Studdert (Digital Image Studio) >> Tel: +61-418-166-870 UTC +10 Hours >> Gmail, eBay, Skype, Twitter, Facebook, Picasa: distudio >> >> -- >> 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. > -- Aloha Photographer Photoblog http://alohaphotog.blogspot.com/ -- 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.
