Just some astro photo's I made some time ago at my lightpolution plagued location.
This was the moment I discovered that my k20d came back from repair with another problem than it had before (extreme noisy, and a strange band).
This was solved by a second repair.
I made these pictures to test how usefull live view is for astrophotography, I do not think I achieved the optimum focus for all pictures yet.
They show the area around M51, near the big dipper (ursa major).
First the resized aps-c image, then two 100% crops
The first crop is the (vastly overexposed) star alkaid of ursa major.
The second crop is galaxy M51.
A*85 at 1.4:
A*85 at 1.4 crop alkaid :
A*85 at 1.4 crop M51 :
Here the lightpolition brightens the background, the exposure of 20 sec was too long.
All other exposure times are the same, 30 sec.
A*135 at 1.8:
A*135 at 1.8 crop alkaid :
A*135 at 1.8 crop M51 :
Next raw pictures I had to stretch the levels seriously.
V125 at 2.5:
V125 at 2.5 crop alkaid :
V125 at 2.5 crop M51 :
A*200 at 2.8:
A*200 at 2.8 crop alkaid :
A*200 at 2.8 crop M51 :
It is clear that the Voigtlander and the A*200 have superior color corrrections, but the speed of the 135/1.8 allows the better recording of M51.
Also note that although the exif records 2.4, and the Voigtlander is sold as a 2.5, the real value is probably closer to 2.8 than 2.4.
George