The problem is that the AntiAliasing filter blocks IR wavelengths.
So, in order to get an IR exposure, you need to have an exposure time
of several seconds, and a tripod, even on a sunny day.
Using this method...removing the AA filter and replacing it with an
IR filter, I can do handheld photography, and compose TTL and shoot
on the fly....no tripods...no long shutter speeds.
Also...as our cameras get more and more advanced, the AA filters are
getting stronger....so somone who wants to do IR work with a D300
would be best off modifying their camera, as the AA filter is too
strong.
Now, there is another alternative...and that is to remove the AA
filter and replace it with clear glass. So, now you buy two screw on
filters, one IR filter and one AntiAliasing screw on filter. You can
now do both kinds of photography and you can choose what wavelength
to block out. Only downside, is that you have to compose first, then
screw the IR filter in (since you can't see through it).
All that work when you could screw on a filter and still have a
normal camera as well. Why?
Morris
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http://qcpages.qc.cuny.edu/~morris/POD
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I've upped my ISO, now up yours.