Nice pencil Paul, now I can see what mine was supposed to look like the other day , well done,
However I have to ask if you can get an image like that with your 400d, (unmodded i presume) why cant I get close to this with the 5d and with more subs than what you took.
My subs were 6mins as well, and at 500 ISO through the Tak, but my result was pretty dismal, I think.
leon
