So, from my understandings.. I have hot spots or dead pixels in my camera. Does any body else know a little bit more about this subject? I found out when I was taking photos at 1 am in the Colorado mountains. I was so excited for the photos! Then I got home and all the photos that didn't have the outer space in them, had little blue, green, red dots! WTF?! So research happened and it seems that they are dead ot hot pixels. How do I get rid of these? Clean the sensor? Replace the camera totally? ( I need a new one any ways) So any suggestions? (I have a Canon 40D and I was shooting with a Sigma 18-125 F3.5- 5)
There is now way those are ALL dead pixels. First of all, each dot appears bigger than an individual pixel. Can you go into a photo-editing program and zoom in 100% and take a screen-shot (or better yet crop as a new picture) to prove they are individual pixels? Second, This is probably the worst reference picture you could have possibly chosen. There are stars all over the photo. (lol!) Third, how long was your exposure? Was your camera moved during this shot? Normally stars would cause streaking if there was camera movement, but depending upon the length of the exposure the stars could have been introduced into the shot right before the shutter curtain closed. These are probably hot pixels, or are an anomaly caused by mirror/camera movement. You should do some test shots and upload them. Take a picture with your lens cap on at all available ISO settings. Take a picture of a white piece of paper (covering the entire picture area) at all available ISO settings. Most cameras also have a function in their menu (probably deep within your menu) to locate dead pixels. This picture is just too busy and inconclusive, and I HIGHLY doubt there would be that many malfunctioning pixels on your sensor.
I will do that tomorrow. The photo was taken with a 1600 ISO at 30Sec shutter. 3.5F The camera never was bumped and was set off with a remote. Also, there was no wind. The dots I am speaking of are where the road and the trees are, not the stars. (places stars could not possibly be) I will take some photos with the lens cap on and check them out. Much appreciated!!
I realize this. This is surprising. I don't think these are artifacts from noise.... My 40d at 1600 ISO does not artifact anywhere near that bad, although I have not done a 30 second exposure at 1600. I have never seen something like this and am now genuinely curious. What were the atmospheric conditions that night? Also, I noticed you were shooting pretty wide-open (f/3.5). Do you have a UV filter or protection filter on your lens? Sometimes these filters (if they are un-coated or do not have proper coating) can produce odd effects (usually flares or purple halos around light sources) and I wouldn't be very surprised if that's what we are seeing here. Were there any other possible light sources in the area? (even your phone would count)
I have an old canon 40d as well, and it has begun to start showing some of these hot spots. For some reason they show up in preview images in adobe bridge but disappear in camera raw on photoshop. You may want to consider cleaning your sensor with a cleaning kit or take it to a service center to clean.