Hi Z,
Perhaps it's becoming geriatric ! Maybe you need a snake-oil cure from one of these spammers that are desecrating the forum.
I don't think a 15 second delay is unreasonable. Perhaps a bit of ageing in the backlights....try fiddling the "backlight" setting in the picture menu. Why fix it if it aint broke. One day I'll develop a rejuvenator for LCDs akin to the old CRT rejuvenators.
Bruce