My understanding is that there is a piece of sticky tape under the front edge of the sensor.  As the sensor is vibrated, dust falls off, lands on the tape and is trapped there.  You don't have to remove the lense, you do have to set the camera upright so that the dust falls on the tape.   DT ----- Original Message ----- From: Canopus56 <canopus56@yahoo.com> To: Utah Astronomy List Serv <utah-astronomy@mailman.xmission.com> Cc: Sent: Thursday, May 5, 2011 11:55 PM Subject: [Utah-astronomy] Canon Xsi 450D CCD well dimensions - what are Some misc questions on the Canon XSi 450 DSLR for astrophotography: What are the dimensions of (1) the CMOS sensor and (2) an individual well on a Canon XSi 450D?  (3) What is the sensor id used in this camera? (4) With respect to the sensor cleaning function, exactly what is that and how does it work?  Assuming that the feature somehow shakes the dust of the chip,  do you have to take the lens out really have the sensor cleaned?  If you leave the lens in, does the cleaning feature just make the dust float around in the camera because it has no way to exit the body? Thanks, Kurt _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php

Kurt, Not sure of the exact name. The sensor is an APS-C Sensor - 22.2 mm x 14.8 mm which makes the 1.6 crop factor. Take 22.2mm and divide it up by the resolution in the width, 4272, the well size is .00519mm or 5.2um. I am not sure if there is a sticky surface to catch the dust or not. The outer filter on the set of filters in front of the CMOS vibrates and is supposed to knock off the dust. I have found it doesnt work very well. They are not hard to clean with a wand and pec pads, or you can just use the cameras dust delete data. It is like an automatic way to do flat frames with the cameras software. Cheers, David On 5/5/2011 11:55 PM, Canopus56 wrote:

Some misc questions on the Canon XSi 450 DSLR for astrophotography:

What are the dimensions of (1) the CMOS sensor and (2) an individual well on a Canon XSi 450D? (3) What is the sensor id used in this camera?

(4) With respect to the sensor cleaning function, exactly what is that and how does it work? Assuming that the feature somehow shakes the dust of the chip, do you have to take the lens out really have the sensor cleaned? If you leave the lens in, does the cleaning feature just make the dust float around in the camera because it has no way to exit the body?

Thanks, Kurt

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