I don't know if this is the right place to post this inquiry but here goes:
There are more than 8000 people who subscribe to this forum so there will certainly be someone who can help me !!
I use an 85mm F1.2 lens for low light terrestrial photos and for controlling DoF. Now you would think that this is an amazing lens for astro work but I think not. Here are two pics :-
Crux in 15 Secs:
http://lh6.ggpht.com/_nmcM5hLJalE/TH...9_sec_9544.jpg
LMC in 20 sec.
http://lh3.ggpht.com/_nmcM5hLJalE/TH...0_sec_9535.jpg
Both pics taken on a 5D with a fixed tripod.
Notice the CA on stars that blow out?
Can anybody please offer any explanation?
TIA and ANY answers will be much appreciated.
Jeremy.