A while back, for no particular reason, I decided I wanted to expose photographs using exposure value or Ev. Exposure value works like the Sunny 16 Rule - a table of different aperture and shutter speed combinations for different situations.

To help me learn I put together a spreadsheet of the shutter speed and aperture combinations and a clear explanation of the actual exposure values for common lighting situations.

Here’s an HTML version of the table.

How It Works

It looks and sounds a bit daunting at a first, but actually works better than a camera’s meter. Modern meters measure light very accurately, generally much better than our eyes. But meters still mostly guess what sort of subject you want to shoot. I say mostly guess, because many cameras now have face detection software, and will meter accordingly.

Since cameras only concern themselves with light, scenes with both distinct highlights and shadows can easily fool meters, even the sophisticated multi-segmented averaging calculations of modern cameras. Dark nights with bright lights, for example, still pose great difficulty.

When we use things like Ev or the Sunny 16 rule, we employ far greater processing power than any camera - human judgement.

Looking at the bottom Ev table, we see a list of scene lighting conditions, ranging from dimmest at the top and brightest at the bottom.

1. Pick one (that best matches your shot obviously).
2. Note the number in the same row at the far left of the table.
3. Find the diagonal row in which the number, or Ev, repeats.
4. Pick one and note the shutter speed and aperture on the column and row headings.
5. If you need to stop action - that is, increase the shutter speed, move further down the diagonal row and note the aperture / shutter speed combination.
6. If you need to increase the depth of field — that is, increase the aperture, move to an Ev futher up the diagonal row and note the new aperture / shutter speed combination.
7. Set your camera’s metering mode to manual and use the aperture / shutter speed combination you selected.
8. To bracket exposure, select higher and lower shutter speeds or increase and decrease apertures; do not change both.

A couple of days ago, while out for a wander with my Sony Alpha 200 and my dog Riz Inevitably, I ended up looking at the Christmas lights and wondered if I could work out a decent manual exposure.

A while back I printed out a copy of my Ev tables and put it in my camera bag, then never really used it. I knew camera meters don’t cope well with Christmas lights and thought I’d give Ev metering a go.

I looked at the bottom table and decided exposure value 4 would work for most houses with Christmas lights, give or take a stop, and manually set my camera’s aperture to f5.6 and the shutter speed to 1 second. I bracketed one stop on either side by changing the shutter speed to 0.5 seconds and 2 seconds. The 1 second at f5.6 exposure was spot on!

Full-sized version of the above.

I thought that worked pretty well. I left the camera set on manual in hopes I can get into a habit of relying mainly on manual exposure. It might take me a while to memorise the majority of exposure values and corresponding lighting situations, but definitely worth the effort, if only for scenes that normally fool camera meters.