With all these talk of how much the AA filters in Canon DSLR reduces image quality, is there a way to remove it to gain the extra 30% or so in resolution. I know astrophotographers routinely remove the IR filter to gain extra red sensitivity. It is my understanding the the IR filter also doubles as the AA filter. Of course if the IR filter is removed the color balance is going to be wrong but maybe one could put a IR filter that doesn't have AA properties in front of the sensor. I would really like to try this as I photograph landscapes and moire is not really a concern but I am not sure whether this would work and I don't want to ruin a Canon 5D.
This is a much more complicated topic than people realize, and certainly more complicated than the discussions that typically take place. You should read this very recent thread on the topic, which included input from some sensor engineers.
That thread is somewhat confused as it mixes up resolution, which is not determined by an AA filter, but by pixel count- with sharpness, which has to do with edge contrast transmission, and is affected by filtering.
Anyway , even if it were technically possible to remove the AA filter, you will be removing more, like the coating on that filter, essential to reduce flare and reflections. The software does not have the anti-moiré feature built into the Leica camera's,etc. At any rate, it does not look like a DIY job to me mechanically. So I think there is a good chance of ruining a good camera.
I believe there are several companies that will remove the filter in order to increase the IR sensivity. I don't know if they do the 5D or only the older rebels and 10D's but it might be something to look into if you were serious. Personally I'd pick up a used Rebel 300D and try that first.
i have thought of this myself and have contributed that my belief is the AA really hurts.
Dan at maxmax.com modified my IR canon 350D and while i never did discuss the project with him, there are other sensor issues, moire among them, and filter coating issues.
i do think it would interesting and should you pursue it, i'd be curious the outcome
A quick search doesn't turn up anything specific. But my understanding is that there is a single piece of glass containing both the IR and AA coatings (if the AA is in fact a coating and not a function of the glass itself).. An email to maxmax would give a definite answer.
Top surface is IR filter
Then the AA filter, consisting of:
- a layer of vertically polarized low-pass filter
- a phase layer
- a layer of horizontally polarized low-pass filter
After viewing the lifpixel tutorials on hot mirror removal, it looks like there is in fact still something covering the sensor after hot mirror removal. Additionally the removed hot mirrors just look like hot mirrors to me. Although this is gleaned just from looking at a few pictures on the Web. Take it for what it's worth.
