This is a simple Minecraft Fabic mod that adds a configurable zoom key.
If you're a content creator, it would be super nice of you if you could mention the mod and point people to my channel here: https://youtube.com/logicalgeekboy
By default the C key is mapped for zooming (as with Optifine) but you can change this in the Controls settings of Minecraft. If you already have the C key bound then you'll need to remap it before it'll work :o)
NOTE: This mod requires Fabric API mod: https://www.curseforge.com/minecraft/mc-mods/fabric-api