How to use sunny 16 rule when it’s not sunny?

Sunny 16 is a helpful rule even when it’s not sunny outside. During the past six months or so, I’ve been really into practicing manual exposures. My goal is to be able to use a camera fluently without a light meter. So far things have been progressing nicely. Sunny 16 has been the backbone of my endeavours. The summer was of course good time to explore the rule, but when autumn arrived, it got a bit complicated. But here’s how you can still get something out of sunny 16 rule even though it’s gloomy outside.

Just a quick recap, in case you don’t know what sunny 16 rule is. It’s a very basic principle of determining manual exposures, that allows you to shoot without a light meter, just in case your camera don’t have one.

In a nutshell, on a sunny day, set your shutter speed closest to your film speed and the aperture to 16. For example, I shoot Tri-x 400 usually at iso 800, which means I’ll set my shutter speed to 1/1000 (closest to 800) and aperture to f16. As long as it’s sunny, you can pretty much forget about metering and just shoot away.

Sunny 16 rule covers few alternative settings. If it’s slightly overcast, set the aperture to f11. If it’s slightly more overcasty, set it to f8. On heavy overcast or completely cloudy set the aperture to f5,6. This is a very simple and bullet proof method on shooting during the summer when it’s mostly sunny. But what to do when october hits and the weather is far away from sunny?

Even though you cannot apply sunny 16 directly on a gloomy autumn day, you can still utilise it by eliminating the sunny day settings. It can get you surprisingly far. When the amount of light drops clearly lower than any of the conditions sunny 16 rule covers, you have fewer settings to choose from. On iso 800, sunny 16 only gets you to 1/1000 on f5,6 so you’ll need to stop down a bit — maybe two or three stops. That’s it.

Determing the f-stop

If you think about it, how many setting you really have left when you know, you can’t use apertures between f5,6—f16? Depending on what kind of lens you’re using, you’re most likely to have only few f-stops left to choose from. On my 35mm f2.8 lens I have basically only f4 and f2,8 to choose from.

Determing shutter speed

The same kind of thinking applies to shutter speeds as well. Now that it’s dark, the fastest shutter speeds don’t cut it anymore. From the fast speeds, you’re going to have  about four options to choose from: 1/500, 1/250, 1/125 and 1/60 — not that many!

Conclusion

Alrighty, so now we know pretty much which settings there are to choose from. The main thing to realise is that we need to stop down from whatever sunny 16 says. When you realise how few options there are left after that, it is considerably easier to determine the correct (or close) exposure. I’d say on a really shit weather, I’d pick something right in the between the remaining options. Maybe 1/250 and f4. I’d argue that it would be a good starting point for a general crappy weather exposure. Slower shutter speeds (like 1/30 and 1/15) tend to be more like indoors or complete darkness territory. But for basic natural light conditions for the darker times of the year, I’d stay between 1/60—1/500.

Also, remember to lean towards overexposure when in doubt. If the settings turn out to be completely wrong, it’ll be much easier to recover the image from an overexposed negative. It will still hold much image information that you can restore in post editing.

Third important thing to remember is the film’s exposure latitude, which is going to be a very helpful asset. Some films require you to be spot on with the exposures, like colour slide films. I like Tri-x because you can be off couple of stops and it will still make an image. It is very forgiving and thus perfect for manual shooting. So far I’ve been able to pull of really good exposures by questimating the settings using the logic I described. I’m not too worried about being off by couple of stops because I’ve always managed to get an image.

If you have any additional tips for manual exposures — I’d really like to hear! Hope you got something out of my observations. Also, feel free to correct if something doesn’t seem to make sense.