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Old 05-08-2011, 03:31 PM
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Merlin66 (Ken)
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Join Date: Oct 2005
Location: Junortoun Vic
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It should be noted that there are two filters in the newer (>350D) Canon cameras.
Filter #2 is a colour balance filter and has some UV-IR cut off. This is usually the filter which is removed to dramatically improve the response to Ha.
However there's another filter Filter #1 which is an antiAlias/ dust filter - this is usually left in the camera. I've found that this filter is also a UV-IR cut filter! and as such blocks everything below 400nm and above 700nm.
So you need to be careful how you specify a "full spectrum mod".
I've arrange for this second filter to be removed and the sensor re-spaced (to maintain focus with standard lenses) for spectroscopy work.
There's a lot of very useful data to be had between 370nm and 400nm.
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