Which Polariser?

I am going to buy my first polarising filter, which I heard is very important for landscapes. I am confused about two things: 1) I currently own a 18-105mm Nikon lens. Should I go in for a 67mm diameter filter, or go for a larger filter and use it now with a step-up ring, so that it remains usable later on if I go for a dedicated wide-angle lens that has a larger filter size? 2) There are many companies and types of polarisers in market, for example, Hoya alone has three types. Which company and type of polariser will be best within Rs. 3500? It would be really helpful if you can answer ASAP. Arka, Kolkata Yes, a polarising filter is very important for landscapes (and for other genres too). When used correctly, it can reduce glare from water, wood, paper, paint, tree leaves, etc. It can also darken blue skies. Remember to buy a Circular Polariser (not a Linear Polariser). Both are circular in shape but their constructions are different. 1. Yes, you could buy a filter with a larger diameter and use it with a suitable ring. Personally though, I would buy a correct size filter – one for each lens I possess. 2. I suggest you go in for the Hoya Pro 1 Digital Circular PL. Its low-profile frame will help avoid the possibilities of vignetting due to the filter. These filters are multicoated, which can reduce/avoid flare and ghosting. Do keep in mind that low-quality PL filters can and do cause colour shifts, and could possibly cause some problems with autofocussing.