This is a 30 minute long exposure I took in northern Colorado at night in the winter. I used a Canon T3i and the kit lens at the widest setting, which is 18 mm. I didn't use any filters. I think I used f5.6 and ISO 100. The camera battery only lasts about 45 minutes in the cold, so that's the longest exposure I could have without buying a battery grip or hooking up AC power. I used the "bulb" setting in the camera shutter speed menu and plugged in a 2.5 mm audio cable, then crossed the end wires together to simulate someone holding down the shutter button on a cable release cord. I took a nap inside the barn while the camera was taking the photo (it was 2 am). Then my alarm clock woke me up and I went outside and unplugged the cord, and I had this photo. Incidentally, learned that it's best to format the camera memory card before attempting long exposure photos. I tried a long exposure once without doing that, and the camera couldn't save the file at the end of the photo. It wasted an hour at night.