Factory source 1/1.8 Pinhole Lens - Classic Camera Lenses – ChuangAn

It’s a series of APS-C camera lens and comes in two type of focal length options, 25mm and 35mm.

APS-C lenses are camera lenses that fit an APS-C camera, which has a different type of sensor compared to other cameras. APS means Advanced Photo System, with C standing for “cropped,” which is the type of system. So, it’s not a full-frame lens.

Advanced Photo System type-C (APS-C) is an image sensor format approximately equivalent in size to the Advanced Photo System film negative in its C (Classic) format, of 25.1×16.7 mm, an aspect ratio of 3:2 and Ø 31.15 mm field diameter.

When using an APS-C lens on a full frame camera, the lens may not fit. Your lens will block much of the camera’s sensor when they work, cropping your image. It can also cause weird borders around the edges of the image since you’re cutting off some of the camera’s sensors.

Your camera sensor and lens should be compatible to get the best possible photos. So ideally you should only use APS-C lenses on cameras with APS-C sensors.