For basic firing at around 40 feet, you need a radio trigger system that can close the flash sync circuit between your Nikon D7200 and the Elinchrom Ranger AS. The key is compatibility with the Ranger’s sync input and the camera’s hot shoe or sync options.

A simple path is:

• a hot-shoe radio transmitter on the D7200
• a matching receiver connected to the Ranger AS sync port

If your Ranger AS has built-in Skyport, an Elinchrom-compatible Skyport transmitter is the most straightforward choice. If not, a universal manual radio trigger set can work as long as you have the correct sync cable for the pack.

You do not need TTL for this use; manual triggering is enough if you only need to fire the light reliably. Also check your camera’s flash sync speed and keep shutter speed at or below Nikon’s standard sync limit when using strobes.

Before buying, confirm:

1. whether your Ranger AS has built-in Skyport reception
2. which sync socket the pack uses
3. that the trigger receiver includes or supports the needed cable