Canon Digital Rebel (300D) Modification Continued

Page 7

by Gary Honis

Camera Disassembly Continued from Page 6:

38. Place LCD unit over two metal posts and attach with three screws:

39. Solder metal shielding at lower right corner:

40. Install ribbon cable from camera back LCD display to hinged type connector. Be sure that the cable inserts all the way into the connector...keep pushing it in until it is fully seated in the connector and lock cable in place by closing the black hinge on the connector.

41. Snap back cover into place on camera. This is a good time to visually check the CF Card Cover Switch as shown below. The purpose of this spring loaded switch is that if the camera is powered on and the CF Card Cover is opened, the switch pops outward and turns the camera off as a safety feature.

I updated this step based on a note from Denis Slattery:

"The CF-card cover didn't work as designed when I first reassembled the camera: popping it open is supposed to cause a power-down. After a lot of squinting I found the cause. There's a tiny spring-loaded plunger switch that pokes up through a hole and engages with a tab on the CF cover. If it's not aligned right it gets squished down and won't detect when the CF lid is popped. I took off the camera cover again and had to tease the plunger assembly a little toward the edge of the camera to get it to line up. Now it works."

Denis also commented on an advantage of this switch not working:

"----- it allows you to pop the CF card without powering down and I took that to be a plus! BUT -- you can't do a firmware upgrade/hack if that switch doesn't work. Something in the camera's operating system looks to that switch for a trigger to load the .FIR file in the root directory. I found out because no matter what I did I couldn't get the hacked firmware to load until I fixed the switch, whereupon it worked immediately."


42. Install rubber port cover into slot in camera body and snap black piece over it:

43. Install two screws in CF card slot:

44. Install two screws in plastic port cover on side of camera. Note that the longer screw is for the top hole near the neck strap bracket and small screw goes in bottom hole near remote port:

45. Install three screws at the bottom of camera:

46. Install last screw on back and insert grey plug. Install the battery and CF card. All done!

Next is the anxious moment.......turning the camera on and testing it to see if all works well. When I turned my camera on, I got a message to reset the date and time. This is normal since the battery had been out for a long time. I reset both and the camera functions all worked well.

Here's another comparison showing that focus of the original camera has been made. The "After Modification" image is much redder with the camera's auto white balance setting. The "After Mod. w/WB" image is an image after the modification but with the camera set at "Custom White Balance" and a Baader IR filter used with the camera lens. The Rebel's "Custom White Balance" involves taking a photo of a white card and setting the camera to use this image to correct the white balance. The Custom White Balance setting is stored in the camera so the color of daytime images with the camera are well balanced.

UPDATE: See Page 8 for methods of Correcting Color Balance including use of color correcting filter and Page 10 for daytime testing with color correcting filter.

___Before Modification_________After Modification__________After Mod. w/ WB

Click on above images for larger images

If you completed the modification and would like to let me know how it went for you, you can contact me at the following email address:

I will add any comments to the modification instructions that might be helpful to others and a link to your site if you wish.

For comments from those that have done the modification CLICK HERE.

CLICK HERE for links to web sites of others who have done the mocification.

See my plans for peltier cooling of the CMOS imaging chip and check back for astrophotographs taken with the modfied camera.

Dark Skies,


Modification Testing:


Part 2: Plans for Peltier Cooling


------Order these two guides by Jerry Lodriguss for DSLR Astro-imaging------

So you now have a modified DSLR for astro imaging. If you are a beginner to DSLR astrophotography, your next best step is to learn all you can about using your modified DSLR. When I complete camera modifications for owners, I get many questions afterward about how to use the camera, including: How to get precise focus? Which exposure settings to use? How to calibrate, align and stack exposures? How to adjust white balance? How to process images?

I am happy to advise and welcome all questions, but the best advice I can give is to order "A Beginner's Guide To DSLR Astrophotography". The book on CD-ROM is authored by Jerry Lodriguss, a professional photographer, amateur astronomer and astrophotographer. Based on his over 25 years of astrophotography experience, he makes it an easy learning process to capture and process astro images. Jerry also has a more advanced book on CD-ROM available: "A Guide to Astrophotography with DSLR Cameras". Consider arming yourself with both these books on CD-ROM, read them at your leisure and maximize your potential for capturing and creating the most spectacular DSLR astro images your modified camera can provide.

Those located in the United States can place orders for Jerry's Books on CD-ROM here:

Domestic orders for "A Beginner's Guide To DSLR Astrophotography".

Domestic orders for "A Guide to Astrophotography with DSLR Cameras".

Those located outside of the United States can place orders for Jerry's Books on CD-ROM here:

Foreign orders for "A Beginner's Guide To DSLR Astrophotography".

Foreign orders for "A Guide to Astrophotography with DSLR Cameras".

To My Astrophotography & Digital Imaging Home Page


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telescope eyepiece astronomy astrophotography televue eyepieces telescopes astronomy eyepiece dobsonian telescope digital camera