Hi Guys I am trying my hand at some wide field imaging using a Sigma 105mm F/1.4 Lens on a Canon 6D11.
This morning I was nearly impossible to get an accurate focus on a bright star as the AF focus dose not work in the pitch black sky.
So I am going to put a small reflector or light some distance down the drive way and AF on that and then turn the lens to manual.
So how far do i need to go to get an accurate infinity focus please.
Is there a calculation for this somewhere.
many Thanks in advance.
Leon
