OM1-MKII: The Right Way of Metering

The OM Systems/Olympus OM1-mkII has 5+ metering modes:

  1. Digital ESP metering aka evaluative/matrix metering
  2. Center-weighted averaging metering
  3. Spot metering metering
  4. Spot metering highlights metering
  5. Spot metering shadows metering


All new dSLRs/mirrorless cameras have similar modes to the first 3 modes of the OM-1, they just call it differently.

And then there’s the manual mode. So what’s the right way? That depends:

  • On the direction of the wind.
  • The age of the captain.
  • What about the exposing to the right?

Does this sound whimsical?

It is and that’s because exposure is whimsical. There’s no right exposure. It just depends. The metering is only one step in the exposure. EV7 = 1/30sec @ f/2 and ISO L100, but it’s also 1/125sec @ f/2 and ISO 400 and… Exposure is only one step.

The second step is the post-processing.

The third and more important step is what’s the purpose or the intent of the exposure? What’s your emphasis? What are you trying to hide in the shadows… This step happens before the metering when taking the photos and after the taking of the photo when doing the post-processing.

Let’s take the example of photos of somebody in the snow, should you over-expose? Everybody will tell you yes, but I say that it depends:

  1. Digital ESP metering/evaluative metering? With the focus on the person in the snow, and the person is at least ¼ of the image, ⇒ no, no over-exposure. 50% of the metering is done on the point in focus and on the points around the point in focus, then there another 10 to 30% that is done on the points that are almost in focus.
  2. Center-weighted averaging metering? ⇒ yes, I would overexpose by 1½ to 2½ EVs.
  3. Spot metering? I would personally place the spot on the face of the person and recompose. ⇒ no, I would not over-expose.
  4. Spot metering highlights? I would place the center spot on the snow, meter and then recompose. ⇒ no, I would not over-expose.
  5. Spot metering shadows? I would place the center spot on the face if the face is in the shade and recompose. ⇒ no, I would not over-expose.

Now let’s change the subject from a portrait of somebody in the snow to the portrait of a black and white dog, where half of the face is white and the other half is black.

  1. Digital ESP metering/evaluative metering? With the focus on the eyes which are almost always back, the photo will be overexposed, ⇒ yes, I would under-expose by ½ to 1½ EV.
  2. Center-weighted average metering? It usually gives me the best results when I deal with faces/portraits…
  3. Spot metering? I would personally take 2 readings, one of the white, the other on the black and then split in the middle. But isn’t that the equivalent of the center-weighted average metering?

Remember that:

  1. All reflective light meters, all brands and models, measure an 18% grey, which was originally set by Kodak for the movies in the early 1910s because it matched the skin of the movie actors.
  2. A reflective light measurement of an 18% grey card is the equivalent to the incident light reading of a hand held light meter.


The spot metering highlights mode and the spot metering shadows mode do not adjust the exposure from the whole frame. It measures the light from the center spot.

It’s up to you to move the important part to the center so the spot can read it and treat it as either a highlight area or a shadow area.

  1. Spot metering highlights: reads the spot and subtracts -2EV.
  2. Spot metering shadows: reads the spot and adds +2EV.