ANNI GETS A NEW TOY!

* Annika1980 wrote :
I've been having lots of fun shooting infrared with my infrared-
converted Totally Digital D60.
So I figured I'd try out a real infrared filter on the Fabulous 5D2.
I got on EBAY and ordered a cheapo Hoya R72 equivalent from a shop in
China. I figured for 25 bucks, what the heck. It finally came today
so I rushed out to try it out, even though it was mostly cloudy.

I quickly learned that the exposure time required when using this
filter will make shooting anything except landscapes impossible.
Here's my first effort which was a 30 second exposure @f/8, ISO 800.
Note the cloud movement during the exposure.

http://www.pbase.com/bret/image/115548398/original

It should produce some interesting effects, although I was hoping it
wouldn't increase exposure time that much.
I really wanted to take some infrared videos with the Fab 5D2, but I
guess I'll have to use a weaker filter for that.
Even cranking the ISO on the Fab 5D2 to 12800 gives exposure times of
about half a second at f/4.

Interesting. I think the reason the exposure times are so much
longer is that the Canon filter over the sensor blocks out a lot,
but not all, of the IR wavelengths. So not much IR light gets to
the sensor even though it does get through the Hoya filter.

I've got a modified camera now. The factory filter over the
sensor is removed and replaced with clear glass. Did this for
astrophotography since much of the light from nebulae is in the
IR range, so makes the camera more sensitive there.

I reckon with one of those Hoya filters on a modded camera, the
exposure times would drop significantly.

If you're interested, this graph shows how the factor filter over
the Canon sensors truncates the IR and UV ranges:

http://www.ezystyles.com.au/ACF.jpg

The cyan line is the one you're looking at. Visible light is
around 400-700nm wavelength. See how the cyan line drops down to
the 700nm end? If you had full transmission there, your exposure
times would go way down.

--
Troy Piggins