Thursday, September 18, 2014

Modified Canon XS and sample photo

I have always struggled with trying to image reddish nebula...never could get enough red to make it look natural. Of course there is a reason. Digital cameras are made for "normal" daylight exposure, what the human eye naturally sees. What is interesting is that digital camera manufacturers have to place an infrared (ir) filter directly in front of the imaging sensor (CMOS) to PREVENT it from capturing the near infrared, because the CMOS is naturally sensitive to the near infrared!
So to capture the near infrared of nebulas in space it would be necessary to REMOVE that filter.
Of course, if you remove that filter the color cast of normal photography will not be "natural" to the human eye. It is, however, possible to compensate for that, to good degree, with the "custom white balance" feature in the camera.

In searching the internet I found a site that gives a clear step-by-step on how to disassemble a Canon DSLR to be able to remove that ir filter,
Since I own three Canon DSLR's I choose to try this modification to the least valuable camera, my Canon XS. Trust me, I was fearful of making a big mistake and ruining the camera for good. But to my happy surprise it was not as difficult as I imagined! True, one needs a good tiny Philips screwdriver (don't compromise here!) but the instructions are so good that only someone with all thumbs need worry about making mistake.

Modification accomplished! Camera tested! Ready to head out to the observatory!

The night was clear, the temps rather warm (didn't put on a light jacket until almost 11 pm), I did a few exposures to see how it works. The images were much red-er than they were before and my technique still needs improvement but I was able in post-processing (using Lynkeos, Preview, and GIMP) to produce this image of the region of the Milky Way north of Cygnus (the Swan constellation) which included the "North American Nebula" and the bright star Deneb.

So if you have an extra Canon DSLR laying around and you really want to do astrophotography of the night sky then this modification is absolutely essential! You can do it yourself or send it in to the guy who runs the above website and he will do it for you for a fee.
When I get a newer Canon DSLR someday I will do this modification to my Canon t3i or t2i, for sure!

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