These days there are over hundreds of lenses you can buy, within any price budget. I've shot on pretty much all of the popular lenses and definitely think you can't go wrong with any of them. But the main trait I want is all of my glass is speed and clarity. Speed is referring to how fast a lens is (1.4,1.8,2.8,etc). The lower the number the more light it can let in for use in low light situations. The next is clarity, most cheap lenses are just as sharp at f/5.6-f/8 as a more expensive lens. What you pay for is the performance at the lower f/stop values. Most lenses that are cheap are very soft wide open and are sometimes unusable. I need my glass to be sharp across the board and able to perform when I need them to. That is why I invested in a full set of Zeiss ZE's.
I've owned Canon L,Sigma art,Rokinon,etc. You name it, I've shot with it. If you are familiar with that lenses you know they vary in price. From $400-$1400. Why pay so much for a lens? I used to think it was crazy to pay so much for just a piece of glass. How much of a difference could it be? The big thing is longevity with these lenses. You pay that high amount because 1. You know they will last for the next 5-10 years and 2. You know they will never fail you in the speed and clarity category. My Zeiss ZE set consist a 35mm 2.0/50mm 2.0/85mm 1.4. I also have a sigma 18-35 1.8 for run and gun and it is AMAZING. These 3 lenses cost about $2500. It's a steep price for just a "lens" but they are sharp as a knife and built like tanks. Point is - you get what you pay for with camera lenses
These lenses have been used on big budget commercials and films and super lightweight, unlike their bigger brother the Zeiss CP2's. They are long focus throws and hard stops. The long focus throw is crucial for nailing accurate focus. Most cheap lenses have fast focus throws, which means the distance from close up-infinity is very close. If you were to barely tap the lens it would fall out of focus. With Zeiss ZE's you don't have to worry about that. It also has hard stops, this means if the lens "stops" when it reaches the closest and farthest focus. Most cheap lenses don't have this and the focus ring just keeps spinning. This can be annoying if you have a focus puller and they don't if they gone past the distance. These 2 features are crucial when looking for a lens kit for filmmaking
Every thing has a negative side. The good thing is there only have 2 flaws, no manual aperture ring. Every cine (cinema) lens has a manual aperture ring. This is for your AC (assistant camera) when they are pulling focus and may also need to pull iris (going from one room to another). It's 100% necessary but when you use it once you'll wish you had it EVERY time. The 2nd flaw is no focus gear for a follow focus but our friends over at cool lux have you covered there, they make custom focus gears for any lens! Amazing company and an amazing product.
At the end of the day it doesn't matter if you have the best camera, the best lenses, the best sound gear. What matters is what you use to create with those and how to tell a story with them. It's about the person behind, not the gear in front. Don't get caught up on just gear. Of course it matters but so does the story you are trying to tell. Try out every gear you can get your hands on and find what works best for you. It's all about maximizing what you have to make an amazing product.