I wanted to try doing star tails again but now that there are street lights down my road I cannot shoot from my back yard so I walked down the road to get away from them. Only after I'd walked the 400 meters or so to get past them and set the camera to bulb did I realise I'd forgotten the shutter release cable and my camera is only capable of 60 seconds before bulb. I tried the 60 seconds first and then had to wait around that again for the camera to do its noise reduction. 60 seconds is not long enough to start seeing the trails so I had to head back to get the cable.
The Street Lights
Before I headed back I remembered something I'd read years ago about how to take star trails without burning the image, something about shorter exposures then stitching/layering multiple shots together in post, however this only works if you don't have to wait for the camera to finish it's noise reduction otherwise there will be gaps in the trails, so I dived into the menu and found the 2 settings, turned them off and tried a 10 second or so exposure and the camera simply wrote the file to the card without any noise reduction processing. Now I could attempt a star tail shot. I upped the exposure time to 4 min (in my back yard now with the shutter release cable) but due to the light from the street lights or my four thirds sensor or something I was doing wrong I was starting to get image burn. I took a few more shots at different times but something was a little off.
Back on the computer in Adobe Elements 9 the raw file looks like the below image, a lot of noise, more than what the camera screen displayed.
I opened the image in Adobe Camera Raw anyway to see if I could remove the noise and without doing anything it has basically all gone resulting in the image below (with only small tweeks)
240 sec exposure, ISO 100, f3.5, 14mm
In the image below you can see the beginnings of image burn/exposure burn or whatever it is called.
80 sec exposure, ISO 100, f3.5
I'll have to do some reading up on how to do it properly, and have another go when the moon and street lights are not around.