Just received a Sunpak 120J TTL Flash for my 503CW, The directions are a little thin. 1) With the 503 ISO set properly, will the flash work automatically with any combination f stop and shutter speed (within the flash range)? 2) If I place a diffuser sock over the flash, will it automatically compensate for the proper exposure. If you have prior experience, I would greatly appreciate your feed back. Best wishes for the Holidays!