The G1 does an awesome job at IR, no doubt. I considered buying a Nikon 900 or 950 some time ago, as those were some of the first cameras that proved excellent at doing IR work. I have lately been thinking about a D30...
I used the Canon 17-35mm L for that shot, and lately have been using my Canon 50mm 1.8. I would rather not upload the original raw file, but will upload a converted TIF that besides conversion settings and a big ugly copyright, will remain unedited. On the copyright, it's not that I don't trust you guys, I don't trust the passerby who might see this and take my images. I don't want any of my full size images floating around, since I am trying to make a living et all (not having much luck at that part yet). The copyright will not interfere with your ability to see the important aspects of the full size file.
Converted using Photoshop CS at the following settings.
Color Temp: 3500
Tint: +15 (default +15)
Exposure: +.5 (default 0)
Shadows: 10 (default 0)
Brightness: 75 (default 50)
Contrast: +60 (default +25)
Saturation: 10 (default 0)
http://www.matthewchase.com/crw_3073.tif
(be warned: 18mb file! I recommend right clicking and choosing "Save Target As")
The bright spot does cause some problems, and seems to be caused by the coating on some lenses. Here is a list that I found elsewhere on this forum, listing which lenses people have had good luck and bad luck with when shooting IR. I haven't used each of these for IR work, so can't confirm the findings of many of these. The bold lenses are those which I have used personally.
Good
Canon EF 17-40mm f/4 L
Canon EF 17-35mm f/2.8 L
Canon EF 24-70mm f/2.8 L
Canon EF 28-135mm/3.5-5.6 IS
Canon EF 28mm f/2.8
Canon EF 50mm f/1.8 MKI
Canon EF 50mm f/1.8 MKII
Canon EF 70-200mm f/4L
Canon EF 75-300mm/4.0-5.6 IS
Canon EF 135mm f/2L
Canon EF 100-400mm4.0-5.6 IS L
Canon EF 100mm f/2.8 macro
Sigma 20mm f1.8
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Bad
Canon EF 16-35mm f2.8 L
Canon EF 20mm f/2.8
Canon EF 35mm f/2
Canon EF 24-85mm f/3.5-4.5
Canon EF 28-70mm f/2.8L
Canon EF 28-105mm f/3.5-4.5
Canon EF 35-80/4.0-5.6
Canon EF 50mm/f1.4
Canon EF 50mm/f2.5 Macro
Canon EF 70-200mm f/2.8L IS
Canon EF 85mm f/1.8
Tamron 70-300mm f3.x-xxx Macro
Sigma 70-200 2.8 ex
Tamron 28-75 2.8 xr di
Tamron 19-35mm f3.5-4.5
I did have a Canon 70-200mm f/2.8L and Canon 28-80L for a very short time to play with, and had my small (52mm) IR filter, but can't give conclusive results of my tests due to not having the correct sized filter. I basically tried using a gobo around the lens leading to the filter, acting like a stepdown device, but it's hard to say if it really worked.