The prime lens that I wrote about is best for taking photographs with (1) Closeups and (2) background blur. I have never taken these ISOs in a moving car in low light!
Nikon just yesterday has announced a f/1.4G lens but I dont think I can afford that price - at close to Rs1 Lakh + compared to around Rs. 15K for this one.
Some things to watch out for when using a prime lens:
1. Takes a few seconds to focus compared to smaller aperture lenses. You can get poor snaps if you do not focus properly. Often a good thing to manual focus
2. If there are two subjects in 2 different planes (Example, people one behind the other), because of low depth of field at high apertures, you can get one of them blurred. Watch out.