u/Fast-Setting-4656

Hello reddit, can anybody help me with my lens? the infinity focus works maybe for 4meters and then its blurry. i've tried every single apeture, focal lenghts and even multiple adapters but nothing seems to work. im not that good with small parts so i havent really looked inside the camera, other than cleaning the lenses. i've always had this lens and im ready to get into the bottom of this. the mist filter i have is a little bit dirty but the photo is the same with or without it