Hello all,
I just purchased a 5Dmkiii, as an upgrade from a 7D. I tried doing my first long exposure night shot last night and came across some peculiar noise issues. If you take a look at the attached raw file, marked GWB.cr2, you will see there is significant rgb "snow" in the image. Some places in particular show pixels that seem to be stuck at 100% of their respective color values. I know the 5D is a noisy camera but, I expected it to be better than the 7D I came from. I've never seen this sort of issue with the 7D sensor, and I've taken quite a few long exposures at ISOs between 400 and 1000.
To investigate further, I took two shots with the lens cap on, for 450 seconds. As such, the exposure time is the same for the test shots as for the shot of the bridge in the GWB.cr2 file. One is at ISO100 and the other is at ISO800 (as you can see from the file names). The ISO100 file looks clean but the ISO800 file looks awful.
Just for comparison purposes, I took a shorter (30s) exposure at ISO800, with the lens cap on. The resulting image showed similar issues although, not to the same extent as in the attached pictures taken at ISO800. Short exposure images taken at higher ISOs, including ISO25600 do not show such behavior. They clean up quite well, in my opinion. To take the comparison 1 step further, I turned high ISO noise reduction on and tried again. The resulting body-cap-on images looked far, far less noisy. As such, it seems to be an issue that is positively correlated with high ISO, long exposure and disabled high ISO noise reduction, together.
Is this normal? I'm worried the camera sensor is malfunctioning. Or is it just me using poor technique?
If you are wondering, I didnt decrease the ISO because I didnt want to wait around for another 4 stops of light to hit the sensor. I assumed that ISO800 wouldn't cause any issues.
Particulars for the GWB.cr2 file:
70-200 f/2.8 mkii at 70mm
f/10
450s exposure
ISO800 for the bridge pic
5Dmkiii firmware 1.3.3
Lightroom 4.4. Imported directly from the card.
High ISO noise reduction and Long exposure Noise Reduction are both turned off.
The other two raw files (ISO100 and ISO800) were taken with the cap on the camera.
Files:
https://www.dropbox.com/s/mirtkfrc82oe9jq/GWB.CR2?dl=0
https://www.dropbox.com/s/i1a690fp98qf05p/BodyCapISO100.CR2?dl=0
https://www.dropbox.com/s/j74yvxbsx50z8ce/BodyCapISO800.CR2?dl=0
Help!
EDIT: THE ISO100 FILE WAS ACTUALLY TAKEN AT ISO50, SORRY FOR THE MISTAKE.
I just purchased a 5Dmkiii, as an upgrade from a 7D. I tried doing my first long exposure night shot last night and came across some peculiar noise issues. If you take a look at the attached raw file, marked GWB.cr2, you will see there is significant rgb "snow" in the image. Some places in particular show pixels that seem to be stuck at 100% of their respective color values. I know the 5D is a noisy camera but, I expected it to be better than the 7D I came from. I've never seen this sort of issue with the 7D sensor, and I've taken quite a few long exposures at ISOs between 400 and 1000.
To investigate further, I took two shots with the lens cap on, for 450 seconds. As such, the exposure time is the same for the test shots as for the shot of the bridge in the GWB.cr2 file. One is at ISO100 and the other is at ISO800 (as you can see from the file names). The ISO100 file looks clean but the ISO800 file looks awful.
Just for comparison purposes, I took a shorter (30s) exposure at ISO800, with the lens cap on. The resulting image showed similar issues although, not to the same extent as in the attached pictures taken at ISO800. Short exposure images taken at higher ISOs, including ISO25600 do not show such behavior. They clean up quite well, in my opinion. To take the comparison 1 step further, I turned high ISO noise reduction on and tried again. The resulting body-cap-on images looked far, far less noisy. As such, it seems to be an issue that is positively correlated with high ISO, long exposure and disabled high ISO noise reduction, together.
Is this normal? I'm worried the camera sensor is malfunctioning. Or is it just me using poor technique?
If you are wondering, I didnt decrease the ISO because I didnt want to wait around for another 4 stops of light to hit the sensor. I assumed that ISO800 wouldn't cause any issues.
Particulars for the GWB.cr2 file:
70-200 f/2.8 mkii at 70mm
f/10
450s exposure
ISO800 for the bridge pic
5Dmkiii firmware 1.3.3
Lightroom 4.4. Imported directly from the card.
High ISO noise reduction and Long exposure Noise Reduction are both turned off.
The other two raw files (ISO100 and ISO800) were taken with the cap on the camera.
Files:
https://www.dropbox.com/s/mirtkfrc82oe9jq/GWB.CR2?dl=0
https://www.dropbox.com/s/i1a690fp98qf05p/BodyCapISO100.CR2?dl=0
https://www.dropbox.com/s/j74yvxbsx50z8ce/BodyCapISO800.CR2?dl=0
Help!
EDIT: THE ISO100 FILE WAS ACTUALLY TAKEN AT ISO50, SORRY FOR THE MISTAKE.