See link https://lens.snapchat.com/20e98eba60bd4718924a1823c29ced90?sender_web_id=b6c34b58-0217-4fb7-aba7-6d13013bfdca&device_type=desktop&is_copy_url=true
To create a Twin lens in Lens Studio, you will need to use a Camera Texture component to capture the camera input and apply some effects to it. For example, you can use a Vignette effect to darken the edges of your image and a Grain effect to add some noise and texture. You can also use a Color Correction effect to adjust the hue, saturation, brightness, and contrast of your image.
To make your lens look like a Twin lens camera, you will need to add some UI elements to your scene. For example, you can add a Screen Image component with an image of a Twin lens camera frame and place it on top of your camera texture. You can also add some buttons or icons to simulate the shutter release or focus controls.
Learn More Here:https://support.lensstudio.snapchat.com/hc/en-us/articles/360051085391-Lens-Studio-Quick-Start