Partial Metering VS Spot Metering.

            Partial and spot metering modes work very similar, the difference being, partial metering takes the exposure from approximately 6.5% of the viewfinder area, whereas for spot metering the brightness is measured using 2.5% of the scenery. On Nikon cameras, spot metering takes the exposure from approximately 5% of the scene depending on the model. As you can see, spot metering on Nikon cameras work very similar to partial metering on Canon cameras.

What is Metering?

 

Metering is how your camera determines what the correct shutter speed and aperture should be, depending on the amount of light that goes into the camera and the sensitivity of the sensor. Back in the old days of photography, cameras were not equipped with a light “meter”, which is a sensor that measures the amount and intensity of light. Photographers had to use hand-held light meters to determine the optimal exposure. Obviously, because the work was shot on film, they could not preview or see the results immediately, which is why they religiously relied on those light meters.
Today, every DSLR has an integrated light meter that automatically measures the reflected light and determines the optimal exposure. The most common metering modes in digital cameras today are:

1. Matrix Metering (Nikon), also known as Evaluative Metering (Canon)
2. Center-weighted Metering
3. Spot Metering

Some Canon EOS models also offer “Partial Metering”, which is similar to Spot Metering, except the covered area is larger (approximately 8% of the viewfinder area near the center vs 3.5% in Spot Metering).

You can see the camera meter in action when you shoot in Manual Mode – look inside the viewfinder and you will see bars going left or right, with a zero in the middle, as illustrated below.

 If you point your camera at a very bright area, the bars will go to “+” side, indicating that there is too much light for the current exposure settings. If you point your camera at a very dark area, the bars will go to the “-” side, indicating that there is not enough light. You would then need to increase or decrease your shutter speed to get to “0”, which is the optimal exposure, according to your camera meter.