Arducam CS-Mount Lens Raspberry Pi HQ Camera, 25mm Focal Length Manual Focus

I bought this lens because I needed a lens with a longer focal length than the 16mm official lens. I cannot get it to focus more than 10 inches in front of the lens. I tried it without any adapters and I tried adding the C to CS adapter and it got worse. I am going to be sending this lens back if I can’t figure out what the issue is. Anybody else have this problem? If so, how did you fix it?

If your camera gets blurry beyond 10 inches, it means that the lens should be threaded toward the image sensor. The adapter will make it worse because it raises the lens to be further from the image sensor.

Therefore to fix that by making the lens closer to the image sensor, we usually turn the focus ring first, and if that doesn’t help, check the back-focus adjustment ring.