Helm Screens - Brightness
Brightness: Try Before You Buy
Manufacturers often describe the brightness—or luminance, to be technically correct—of a display in candelas, a unit of measure shown on spec sheets as cd/m (candelas per square meter). To further confuse us, salespeople in conversation usually refer not to candelas but “nits,” which means the same thing. The more nits, the brighter the screen image. The brighter the screen, the more likely you can read it outdoors.
The recently released iPad3, for example, sports 350 nits. The Raymarine e-series MFDs boast 800 or 1,000 nits, depending on model. Garmin displays are capable of 1,000 or 1,200 nits, depending on model. Simrad used to boast that it had the brightest MFDs with 1,500 nits but now others make the same claim.
One nice thing about designing a helm with marine monitors, such as those from Nauticomp, KEP Marine, VEI, and others is that they come in two or three brightness levels. For example, a KEP Marine 19-inch pilothouse monitor has 400 Nits—not much more than the iPad. The same KEP monitor for direct sunlight on a flying bridge has 1,000 nits, which raises the price from $7,995 to $10,495. With MFDs, as opposed to monitors, customers don’t have a lower-cost option; they pay for a sunlight-readable screen whether they need it or not.
Contrast is another spec that helps predict a screen’s daylight viewability. It is expressed as a ratio such as 600 to 1 or 850 to 1. The ratio represents the difference between white and black on the screen. Higher contrast makes for sharper images.
Another frequently cited spec is viewing angle. Expressed in degrees, viewing angle quantifies your ability to read a display when looking at it from the side. An 80-degree viewing angle is considered very good.