When I first ripped apart my camera, one thing was bugging me. I purchased the Baader BCF-1 filter replacement because I didn’t want to deal with clip-ins and I use this camera for daytime photos as well. That’s great, but I couldn’t find a definitive answer as to whether or not autofocus would still work if I removed the outside low pass 1/anti-alias/moire filter. The interwebs seemed to indicate that autofocus would not work with the filter removed, but there was no definitive answer for my camera model, or really any other. So after reading for a couple days, the Google box failed me and I decided to rip apart the camera again and find out for myself.
I won’t hold you in suspense. The answer is yes, at least for my 18-55mm and 75-300mm kit lenses, autofocus works without any issue or need for shims. Oddly enough, it seems to achieve focus faster with the low pass filter removed.
Here are a couple examples of focus and color correction. The focus is a touch out at the top of the image, but that’s my fault for unevenly tightening the spring-loaded screws that attach the sensor. I didn’t test with a custom white balance for two reasons.
- I only shoot in RAW, and white balance is largely irrelevant in RAW format. I use Photoshop and the RAW editor lets you tweak the histogram/color balance before opening the image in Photoshop. I always play with the colors a little anyway. It’s not a perfect balance, but eyeballing it for an example took less than five seconds.
- It was night, and I didn’t have the proper light to make a custom white balance
My wife is an Illustrator so I had a box of colored pencils and some sketch paper to use for a perfect example right in front of me.
Below is a shot at 18mm. You can see the white paper as a point of reference.
I hope someone finds this helpful! I know if I had this information ahead of time it would have saved me from taking apart the camera twice. Sometimes you just have to figure things out for yourself! I can’t say with 100% certainty it’ll work this way for every camera, but for the Canon T1i/500D, and I would suspect most if not all Canons with this filter design, it should work the same. Now I just have to wait a couple days for the clouds to clear so I can try this out with my new H-alpha filter.
Clear Skies, Bleary Eyes – KA