I'm a hobbyist so I lack the knowledge of experienced photographers. I know how to take shots and get the results I'm looking for but that's sort of the extent of my knowledge. My achilles heel is when it comes to technical information.
I currently shoot with a canon 50mm 1.4 and a canon 24-70 2.8 on a 5D mk 2 I acquired about a year ago. The 24-70 is nice but I enjoy shooting with prime lenses more so I'm looking to sell it and buy a wide angle prime lens. I know there are a lot of options out there but for many years I've wanted to own a carl zeiss lens and I think that will be my next purchase. The distagon lenses are fairly affordable on the used market and seeing how I've wanted one for a while I think I'm going to give the manual lens a shot.
So zeiss makes a 25mm 2.0, 25mm 2.8 and a 28mm 2.0, and one of the things I'm having a hard time wrapping my head around is why they would produce the 25mm in both f/2 and f/2.8. Obviously the f/2 is faster, and it can shoot at f/2.8 when stepped down but I imagine there is a reason they make both lenses and not just the f/2. Additionally these three lenses are so close to one another that again I'm confused at to why they dont just make one lens, especially in the day and age of cutting manufacturing costs and manufacturing complexity. Are each of these lenses for different purposes? What am I missing here?
I'll be using the lens for street and nature photography as well as car shows. Given that is there one that stands out more than the others for my needs?