This thread is a great resource for people who want to attempt a cold finger mod.
My contribution may not be so useful as it is a digic II model without live view, but as the 400D's are becoming throw away items I considered it to be a good experimental platform. I currently use a 1100D in a cold box with gives me very consistent 15-16 EXIF temps, but happy to add a DSUSB and spend more time on focus and framing to experiment with the finger cooled 400.
Having got stuck into it, I have also found this model to be very accepting of a large chunk of copper inserted into it. The large CF slot makes a very handy pathway onto the back of the chip requiring no mods to the camera case, and having removed the pin holder, the remaining CF card infrastructure makes a nice framework to support the finger. It will be full spectrum with no filters or clears so in turn has only received a 4 resistor (4 x 22ohm) array packed into the old filter housing. As with my cold box setup, some hot-side air will be directed onto the field flattener body to take care of the glassware and filters leading into the camera body. I will try out how effective self amalgamating tape is as an insulator on the finger leading out of the body, and also my old friend 'shoe goo' to take care of the insulating of the area around the back of the sensor.
Should be fun
