Photos are darker that the original in Lightroom on the IPad

You're probably shooting raw images. By default when you shoot raw images, the camera setttings are not used by Lightroom and it will show its normal interrpretation of the raw data. It appears you have some sort of HDR mode enabled on the camera such as dynamic lighting. On this image try selecting the "camera settings" preset (it will be in the defaults section). On Many cameras, this will read the in camera settings and try to mimic them. If you want Lightroom by default to use camera settings, go to the main screen, tap the gear icon and select import. In the screen that pops up there is a section called Raw default settings. Set this to "Camera Settings". New imports will now use the in-camera settings for raw files if the camera is supported for this.