actually i found it's quite easy to active the hidden iso value. i tried to set the hidden iso value (even they are not listed in menu) with PC software based on EDSDK, it works fine. no firmware modification required. i've tesed 350d with iso from 6 - 3200, all iso <= 1600 are worked, but 3200 not. i guess some firmware hack is needed to extend the high iso.
i'm keep working with 350d. cheers!
看樣子 350D的使用者也快要有春天了
然後 I have found that 400D flash light sync. speed is not 1/200; it is ok while 1/250, can crack it?