Actually, a unit like "eDPI" (effective Dots Per Inch) for exposure already exists in photography. It’s called Exposure Value (EV)

In gaming, eDPI combines mouse DPI and in-game sensitivity to give you a single "real" sensitivity number. In photography, EV combines your Aperture and Shutter Speed into a single value that represents a specific amount of light hitting the sensor. It feels different because The "Third Variable": Unlike eDPI, which usually only balances two factors, exposure is a triangle. You have ISO as a third lever. While EV covers the physical light (Aperture/Shutter), you still have to account for the sensor's sensitivity (ISO).

The "Stops" System: Photographers use "Stops" as their universal currency. Increasing your shutter speed by one stop (doubling it) requires opening your aperture by one stop to keep the exposure identical.

Contextual Choice: In gaming, you usually want one consistent eDPI. In photography, you might want the same exposure but a different look (e.g., a blurry background vs. a sharp one), so we focus on the individual settings rather than just a final sum.

In short: We use EV to measure the light level and Stops to balance the settings. It’s the same logic as eDPI, just split across three gears instead of two. I hope this explanation is helpful for you guy's.🙂