haha thanks! its the rainy season now =[
having my butterfly frenzy now, i think those shots were done inbetween my forest trails at macritchie where the sky was pretty decent.
actually when i see ur pictures and i want to get out of sg to shoot!
jaimambo - it depends on your camera, for some reason, my model (pentax k100d) is able to focus even with the filter on.
surely, you would have to compose before putting the filter on though, otherwise very hard to see.
you also need a tripod.
for 400d, the exposure timings typically will be extremely long - i'm thinking even for a relatively sunny day, when i was helping someone with a 400d once, the settings were quite painful, f/4 with iso 100? 200? and definitely in the region of 30 seconds. might have remembered wrongly though, but 400d is definitely not very sensitive to ir and requires longer exposure time than most other cameras like the nikon d70 or pentax k100d
yes, with the filter on i cant see anything throught my viewfinder. basically set up the whole shot focus yada yada and then screw the filter on, then set the exposure and aperture to get the correct exposure. why i mentioned aperture is because u might be using a really big hole and isolating the background or having a faster exposure during windy days, to minimize or capture the "fuzzyness" of the moving leaves and also waterscapes... depending on ur cup of tea.
exposure wise i think canons need to go up to 20-30s for a decent ir as the sensitivity isnt very good.
think night86mare had explained it quite well