Take a look at the image below. Just to let you know that I've shoot 5 exposure bracketing so that I can post process the image as HDR later on. What I've found at the 30 seconds exposure image, there is a lot of hot pixel showed up and clearly noticeable especially on the darker area.
If you are shooting SOOC (straight out of camera) you might say that its too small to be noticed. But for me, when I performed the tone-mapping on those images, the hot pixel will show up like nobody business!
Below is the image after post processing. Noticed the small white dots on my watermark below? Do you know how hard to get on top of this private building??! ~[ I'm stressed!! ]~
If shoot less then 30 seconds, the image is perfect - not a single hot pixel available. See two images below:
But still, I will keep my EM1 as my daily candid, macro and street photography buddy.