What is the fine-grained topic of the following text: **The Nissin i40 and i60 flashes have a magnetic sensor built in to adjust the zoom when the integrated diffuser is used, and the powerful magnets in our MagGrip may trigger this sensor and force the flash into wide angle mode. Only return the topic.
The impact of MagGrip magnets on Nissin i40 and i60 flash zoom adjustment.