Film Photography

Using Sunny 16 to check your camera’s meter

Something might not be right with the meter on my black Olympus OM-1. I’ve taken it out lately on some bright days and the exposure settings that give me that horizontal needle in the viewfinder aren’t agreeing with the Sunny 16 rule.

Olympus OM-1

I’ve said for years that I want to get better at reading the light with my eyes and setting exposure manually. It would let me shoot any non-metered camera in my collection without having to fumble with an external meter. But it also alerts me when one of my old cameras’ meters might not be accurate anymore.

I expect most photographers who learn this skill start with Sunny 16. I did, and I have it down well enough. I’ve even occasionally adapted it down to f/8 as the resulting faster shutter speeds are sometimes useful. (See Mike Eckman’s useful article on his “Outdoor Eight Rule” here for a dead-simple related technique.)

My OM-1’s meter doesn’t appear to be so far off that the good exposure latitude of the Kodak ColorPlus film inside shouldn’t cover it. I’m relying on the meter to see what happens.

But it’s very nice to know that I can sanity check any camera’s meter against Sunny 16 and adjust my shooting accordingly — even “go commando” and ignore the meter if I must.

If you’re unfamiliar with the Sunny 16 rule, here it is. Most negative films, both black and white and color, have enough margin to give you a usable image with these settings.

First, set the shutter to about the inverse of your film’s ISO. So for ISO 100, set the shutter to 1/100 or 1/125, whichever one your camera has. For ISO 200, it’s 1/200 or 1/250. For ISO 400, I don’t know a camera that has 1/400 so go with 1/500. Close enough is good enough.

On a normal sunny day where you see distinct shadows, set the aperture to f/16. On a cloudy day when the shadows soften, go with f/11. On a heavily cloudy day when the shadows are barely visible, use f/8. When it’s overcast enough there are no visible shadows, use f/5.6. A final tip: if the sun is blazingly bright and glaring, go with f/22 if you have it.

If you learn this well enough, you too can easily sanity check the meter on any camera you own. Set the ISO to 100, gauge the light and guess the shutter speed you should use at f/16, and then:

  • On a full manual camera, set the aperture to f/16 and the shutter speed according to the Sunny 16 rule and see where the exposure indicator lines up. If all’s well it should indicate close to proper exposure.
  • On an aperture priority camera, set the aperture to f/16 and see what shutter speed the camera chooses. If all’s well it should choose something close to 1/100 on a sunny day, 1/50 on a cloudy day, 1/25 on a heavily cloudy day, and down from there.
  • On a shutter priority camera, set the shutter according to the Sunny 16 rule and see what aperture the camera chooses. If all’s well it should choose something close to f/16 on a sunny day, f/11 on a cloudy day, and on from there.

Sunny 16 isn’t exact science. When I say “close” above, I mean within a stop or maybe even two of correct exposure. But if you set your camera to 1/100 and f/16 on a sunny day and the camera indicates strong over- or under-exposure, either you have a bad battery or your meter is faulty.

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