Have actually done the light leak test in AV mode today to see what happens. Right after start up, the exposure was 6 seconds with LED off. Turned the LED on, 8 second exposure rime. After it was powered up for a few minutes, times were a mix of 13 & 15 seconds, mostly 15, whether the LED was on or off. I honestly can not see a difference. Not sure about anyone else's results, but if you do the test my results indicate that it would be recommended to leave the camera on for a little while before testing. It would seem that the results do vary during an initial warmup stage.