Artifacts on long exposure

Hey Everyone

Does anyone have an idea of what is causing this, the one brights dot and the thousands of other dots? Don't know if its dust or a sensor problem or what but its consistently in the same position and worsens the longer my exposure is.

This is a massive problem right now cause I have a cave photography expedition this weekend!!!!!!

Please Help!!

Which body are you shooting with?

Most (all?) Canons have a Long Exposure Noise Reduction setting.

Each long exposure picture you take will be followed by an identical length black picture the camera takes to get rid of such artifacts (you're getting them from the sensor heating up, if memory serves)...

Anyways...it'll mean that you have to allow TWICE the time for each picture and you'll run out of batteries sooner (as in with fewer frames), but it's worth it to get rid of the white spots.

Ah ok cool, im on the 550d. is the one big bright dot caused by that as well?

To be honest - a streak like that, wouldn't there rather have been a light source in the sky? Try shooting a long exposure black frame (lens cap on) - you should not get any.

yep, use the noise reduction. Like increasing the ISO, increasing exposure times will lead to noise.