I've recently bought a Pentax K-50 and I'm looking to move beyond the 18-55mm kit lens. I'm a beginner hobbyist and my main aim is to take beautiful photos of Tokyo, where I live. So mostly street scenes and landscapes, and a lot of night photography, sometimes in the rain. From some reading around the subject, it seems like what I need for these things is a fast "standard" prime lens.
I understand "standard" to mean around 30mm on an APS-C like the K-50. The problem is that there doesn't seem to be an affordable prime in this range, with the exception of the Pentax DA 35mm F2.4 AL. This lens is very cheap, but as a beginner I don't know whether this is because it has significant limitations. Once I buy a lens for this purpose I'm unlikely to ever buy another one, so I want make sure this will be the right purchase in the long term.
My specific questions:
At f/2.4, the maximum aperture is not as wide as many other prime lenses provide, and I'm wondering if that will limit me when it comes to night photography. I am a beginner and have no experience to judge this; I've only used the kit lens, whose maximum aperture of f/5.6 does make it hard to get the shots I'd like.
Initially, before I fully understood how focal length relates to field of view I had my eye on the Pentax DA* 55mm F1.4, which is just about within my budget and is weather sealed. Is there a similarly-priced lens that I've missed that has the advantages of this lens (very fast, well-regarded optics and preferably also weather sealed) but with a wider field of view?
Alternatively, is the DA* 55mm F1.4 itself a reasonable choice for what I want to do? Its field of view is similar to my kit lens when fully zoomed in, and it feels to me like that's too narrow, but maybe once I'm more practiced at composition that will be less of a problem, I really don't know.
In short, I'd like to know whether the DA 35mm F2.4 AL is suitable for my purposes as I've described them, and if not, what the alternatives might be.