With its compact appearance and lightweight design, the Nissin i40 can easily be stored in any photo or jacket pocket and is ready for use in any situation in a short time. Many people do not use an external flash during the day because it takes up space and restricts comfort of movement. Typically, they trade comfort for inflexibility in how the light is directed, especially in strong backlighting caused by the sun. The Nissin i40 changes this, allowing photographers to enjoy both comfort due to its extremely compact design and flexibility in lighting with all its photographic possibilities.

The professional design of the flash head indicates that this small unit belongs to the big leagues. It can be tilted horizontally by 180° to the right and left and tilted by 90°. The variety of possible angles makes indirect flashes easier and more versatile. Advanced users benefit from a maximum flash sync time of up to 1/8000 second when using the second curtain. This feature can be crucial when photographing moving subjects. The i40's full range of shutter speeds spans from 1/800 to 1/20000 second. Shorter shutter speeds allow for more flashes to be emitted, ensuring uniform flash illumination. Very short shutter speeds are particularly interesting for portrait photographers who want to use flash in daylight while maintaining a large aperture for a shallow depth of field.

The integrated LED video light is a notable feature for such a compact flash. Nissin is specifically addressing the trend towards video functions in photo cameras. This means that even without a separate video lamp, attractive film sequences can be captured for up to 3.5 hours with fully charged batteries or rechargeable batteries. The strength of the LED light can be adjusted in 9 stages to suit individual requirements.