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Hap Griffin DSLR Modifcation |
Review date: October 2008
Purchase date: May 2008
Retailer: Hap Griffin - Imaging Infinity
Price: US$380 (not including shipping charges)
The Canon EOS 40D, like all consumer digital cameras, is optimized for response at the visual wavelengths of light. Everything from the sensor's Bayer matrix of tiny filters and the built-in infrared absorption filter to the Digic processor is optimized to yield images that look natural to our human eyes. That means certain wavelengths of light that the CMOS sensor would normally record must be blocked or ignored. This is done partially by a filter placed in front of the CMOS sensor that blocks a lot of red light (since human eyes are not very sensitive to red light, when compared to green and blue, and therefore don't perceive very much red light in the natural world).
Unfortunately for astrophotographers, the light that is blocked includes the astronomically significant hydrogen alpha emission line, which is located at 656.3nm. Many deep sky objects in our galaxy are rich in hydrogen alpha and emit light at and around the Hα emission line. Fortunately, the IR-blocking filter can be removed or replaced and a lot of sensitivity to Hα can be restored. (See my article on the various types of DSLR modifications for more information.) But it's not a simple matter to replace that filter.
The modification can be a DIY project or your camera can be sent to an individual or company to have the service performed. The benefit of having the service done by someone like Hap Griffin is obvious... he's performed the operation dozens (if not hundreds) of times and is therefore very familiar with the process, the parts, the tools, the potential surprises, and everything that goes with it.
That's the route I chose to go. I had Hap Griffin replace the stock IR-blocking filter in my Canon EOS 40D with a filter from Baader that permits more red light through to the sensor but still blocks UV and IR to control star bloat, chromatic aberration, and other anomolies associated with allowing a wider spectrum of light through to the chip. The filter glass is also of the same thickness as the original IR-blocking filter so the refractive index is maintained and the camera's autofocus is still fully functional and accurate.
The Summary
The astrophotographic benefit of replacing the stock IR filter is obvious and well-documented. So this review focuses on the service itself.
- Price: While a bit expensive, given the options, Hap's price is quite reasonable and actually better than most others who offer the same service. So, in that context, it's difficult to complain about the price.
- Quality: As an individual who is picky with his equipment and keeps it exceptionally clean, this was a concern. Would it come back scratched? Would something be out of alignment? Rest assured, Hap's service is very clean. There's absolutely no sign that the camera was ever opened. Flat frames show no sign of anything protruding into the field of view (like glue), no new dust spots, hairs, or other potentially problematic artifacts.
- Warranty: Unfortunately, but understandably, Hap cannot provide a warranty on the entire camera once the service is performed. While he backs his work, he cannot take responsibility for a future camera failure unless it's clearly related to his modification service. However, he does back up his own work, of course. Other companies, like Hutech, will warrant the entire camera if you purchase a modified model from them.
- Communication: This is the one area that I found slightly lacking with Hap's service. While there was nothing necessarily negative here, it would've been nice to receive an email from him stating that he's received the camera and he expects to return the camera on X date. I had to contact him in order to get such an update.
- Turn Around Time: Hap was quite quick. Even though he couldn't tend to my camera for a few days after receiving it, he was still quick with the service and it was on it's way back within one week of him receiving it. No complaints here (especially considering the camera had to travel from one coast of the U.S. to the other and back).
Conclusion
I'm pretty confident that I could have performed this modification by myself. Getting all the tools, creating a clean work environment, and finding the time was the difficult part. It's great that there are several places to which a person can send their camera to have this service performed. The 40D is my second modified camera. My former 20D was modified by Hutech. Given Hap's price, speed, and quality of service, I have no reservations in recommending him to anyone looking to have their DSLR modified.
As for whether or not to do the modification in the first place... that's a personal decision that you'll need to contemplate seriously. As a semi-serious astrophotographer, I consider the cost and drawbacks of the modification worth the extra sensitivity. Not everyone will see it that way.
Related Links
Hap Griffin's "Imaging Infinity"
CaliforniaStars.net article on DSLR modifications
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Click an image below for a larger view.
 Canon EOS 40D internal filters
Images from Modified Canon EOS 40D
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