I have one like this too. DS-2CD2342WD-I. Is it possible to disassemble and correct the focus? Came from factory with very soft focus. I consider it unusable as it is.
Yes, you can adjust the focus. There is glue on the lens that will need to be scraped off in order to adjust it. I must have been lucky with the 4 I bought in January as the focus is spot on- what lens do you have on them?
PS: If they're under warranty why not return them?
I changed the lens in one of my DS-2CD2342WD-I cameras today. The factory glue was very hard to remove. I ended up scraping off as much as I could and then wrapped the lens in paper before grabbing it carefully with a pair of pliers(!) Be sure to hold the module by the lens mount if undoing it this way.
Luckily, it didn't take a lot of effort with the pliers.