The camera does not appear in the list of cameras
Make sure your Snappic version is at least 1.20
Make sure your iOS version is at least 14.2
Check if the camera is turned on and has power
Check the cables and adapters to ensure everything is connected properly. If you are using a hub, try a direct connection without the hub (if supported by your iOS device and cable). Refer to this guide for connection details.
Try a different cable/adapter.
Check to see if the app has the necessary permissions to access cameras. This can be found in the iOS Settings app, under Settings > Snappic > Camera.
Check to see if the app has the necessary permissions to access image files on the camera's memory card. This can be found in the iOS Settings app, under Settings > Privacy > Files and Folder > Snappic.
Some camera's don't allow tethering while Wi-Fi is active. Disabling Wi-Fi on the camera may help.
The flash does not fire
Some Canon cameras will not fire a flash when the live preview is active. This only affects certain flashes. The built-in flash, Canon branded flashes, and some compatible 3rd party flashes should work, but others may not.
Changing the Silent Lv Shoot option on the camera to disabled fixes the issue, but not all cameras have this option. This setting must be changed on the camera, it can't be changed from the app. Refer to your cameras manual to see if it has this option, and where to find it.
Most mid to high end Canon cameras should have the Silent Lv Shoot option. If your camera does not have this option, try update the camera's firmware. If that doesn't help, you will need to either use a different flash, or a different camera.
The live preview is too dark
This can happen for a few reasons. Make sure the lens cover is not on the camera lens, and that the camera settings are not causing the dark preview (ISO, Shutter Speed, and Aperture are the main settings that can cause this). If your camera is set to Manual mode, try the Auto mode to see if that helps.
If the live preview is too dark, but the captured image comes out ok, the issue is probably being caused by the flash. The flash is creating enough light when capturing to light up the environment, but before capture it isn't creating any light, making the live preview too dark. There are three potential solutions to this:
Some cameras have an Exposure Simulation option. Disabling this can help. This setting must be changed on the camera, it can't be changed from the app.
If your camera does not have an Exposure Simulation option, or you want more flexibility, you can use the app to choose different camera settings for the live preview. This article has the details.
Use sufficient constant lighting instead of a flash.
When adjusting the live preview settings, nothing happens
If your camera has the option, enabling the Exposure Simulation option can help with this. This setting must be changed on the camera, it can't be changed from the app.