The Saga Continues at DVinfo.net

Alex Bornstein · July 1st, 2005, 03:28 AM

Hello once again!

I recently finished shooting a small scale short film with the XL2 and had a complete blast. The lenses used performed amazingly and I can't wait to use it again!

While changing the lenses though (prepping the camera for storage), I noticed what seemed to be a speck on the CCD. I cannot determine if this is part of the CCD sensor or not. There has not been ANY change to the image quality that the camera produces (fed it to a 25" TV as well to check), so I'm inclined to adopt a "don't fix it if it ain't broke" mindset...but if something is wrong with the camera I'd like to get it rectified. Anyway, should I just let a sleeping dog lie (if it's anything to begin with)?

Thanks for all your help! This place has been invaluable since I began researching the XL2.

Chris Hurd · July 1st, 2005, 06:13 AM

When you changed lenses, most likely you did not see a speck on the CCD. What you saw was probably a speck on the CCD block prism face. On the camera body, when you take the dust cap off and look inside the lens mount, you can see what looks like a CCD in there, but actually you're really looking through a prism at the three CCDs superimposed on each other. The surface of the prism block sort of protects all that stuff inside. Each CCD is hard-mounted on the prism; there's no way for dust to get in there. You do need to keep the outer prism face clean though, and free of fingerprints, dust and so on.

Alex Bornstein · July 1st, 2005, 12:08 PM

Quote:

Originally Posted by Chris Hurd

When you changed lenses, most likely you did not see a speck on the CCD. What you saw was probably a speck on the CCD block prism face. On the camera body, when you take the dust cap off and look inside the lens mount, you can see what looks like a CCD in there. You're looking through a prism at the three CCDs superimposed on each other. The surface of the prism block sort of protects all that stuff inside. Each CCD is hard-mounted on the prism; there's no way for dust to get in there. You do need to keep the outer prism face clean though, and free of fingerprints, dust and so on.

Gotcha. So will it be best to just stay vigilant about dust on the faceplate and only clean once there are any imaging issues?

Chris Hurd · July 1st, 2005, 01:59 PM

I'd visually inspect it closely every so often and clean it if needed. Try not to touch it of course, but if you do, it's no big deal.

Alex Bornstein · July 1st, 2005, 11:45 PM

Quote:

Originally Posted by Chris Hurd

I'd visually inspect it closely every so often and clean it if needed. Try not to touch it of course, but if you do, it's no big deal.

Do I need to adopt any specific cleaning regimen with this part of the camera?

This has me confused still haha. I cannot tell if it is a speck of dust or something else. It is only visible when a little bit of light bounces off of it. I'd be more concerned if there were any imaging issues, but I'd be darned if there were any...

Chris Hurd · July 2nd, 2005, 12:12 AM

Just clean it like you would a lens; at least that's what I do.

Greg Boston · July 2nd, 2005, 09:05 AM

Alex,

Keep a small can of compressed air made just for this sort of thing handy. As opposed to mechanical cleaning by touching the prism face with a cloth.

As to why you aren't seeing this 'speck' in your image, that's because it's so close to the ccd block that it is completely out of focus. In fact, we had an engineer at the semiconductor company I used to work for who came up with a way to keep dust specks far enough away from the reticle(the actual circuit pattern on a glass plate) so that they were completely out of focus and would not transfer to the face of the silicon wafer. His solution was an additional glass plate called a pellicle where any dust particles would land which sat at a distance so as not to focus on the wafer. It was a tremendous boost to device yield per wafer.

In short, use compressed air first, then mechanical cleaning if necessary.

-gb-

July 1st, 2005, 03:28 AM	#1
Alex Bornstein New Boot Join Date: Jun 2005 Location: Orlando, FL Posts: 16	The Saga Continues Hello once again! I recently finished shooting a small scale short film with the XL2 and had a complete blast. The lenses used performed amazingly and I can't wait to use it again! While changing the lenses though (prepping the camera for storage), I noticed what seemed to be a speck on the CCD. I cannot determine if this is part of the CCD sensor or not. There has not been ANY change to the image quality that the camera produces (fed it to a 25" TV as well to check), so I'm inclined to adopt a "don't fix it if it ain't broke" mindset...but if something is wrong with the camera I'd like to get it rectified. Anyway, should I just let a sleeping dog lie (if it's anything to begin with)? Thanks for all your help! This place has been invaluable since I began researching the XL2.

July 1st, 2005, 06:13 AM	#2
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	When you changed lenses, most likely you did not see a speck on the CCD. What you saw was probably a speck on the CCD block prism face. On the camera body, when you take the dust cap off and look inside the lens mount, you can see what looks like a CCD in there, but actually you're really looking through a prism at the three CCDs superimposed on each other. The surface of the prism block sort of protects all that stuff inside. Each CCD is hard-mounted on the prism; there's no way for dust to get in there. You do need to keep the outer prism face clean though, and free of fingerprints, dust and so on. __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

July 1st, 2005, 01:59 PM	#4
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	I'd visually inspect it closely every so often and clean it if needed. Try not to touch it of course, but if you do, it's no big deal. __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

July 2nd, 2005, 12:12 AM	#6
Chris Hurd Obstreperous Rex Join Date: Jan 2001 Location: San Marcos, TX Posts: 27,368 Images: 513	Just clean it like you would a lens; at least that's what I do. __________________ CH Search DV Info Net \| 20 years of DVi \| ...Tuesday is Soylent Green Day!

July 2nd, 2005, 09:05 AM	#7
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	Alex, Keep a small can of compressed air made just for this sort of thing handy. As opposed to mechanical cleaning by touching the prism face with a cloth. As to why you aren't seeing this 'speck' in your image, that's because it's so close to the ccd block that it is completely out of focus. In fact, we had an engineer at the semiconductor company I used to work for who came up with a way to keep dust specks far enough away from the reticle(the actual circuit pattern on a glass plate) so that they were completely out of focus and would not transfer to the face of the silicon wafer. His solution was an additional glass plate called a pellicle where any dust particles would land which sat at a distance so as not to focus on the wafer. It was a tremendous boost to device yield per wafer. In short, use compressed air first, then mechanical cleaning if necessary. -gb-