The "Sunny 16" Rule


We should begin this treatise by clearly stating that the Sunny 16 rule is nothing new, and if anything it’s a formula that’s been kicking around since the early days of picture taking. It’s also worth noting that the Sunny 16 rule has held true through every technological breakthrough from tinplates straight through modern-day digital imaging. It held true way back then and it holds true today.

In a nutshell, the Sunny 16 rule is a simple method of establishing a correct exposure when taking pictures outdoors without using a light meter. The premise of the Sunny 16 rule is that sunshine is a constant source of illumination, which depending on a short list of variables, is easy to classify. You have clear, sunny skies, hazy days, slight overcast, heavy overcast and precipitation in the form of snow, sleet or rain. Add to the above parameters the reflective nature of the surroundings, i.e. city/suburban streets, the beach, snowscapes and high/low altitudes.

The starting point for establishing the correct exposure is to set the only non-variable part of the equation, specifically the f-stop of the lens, which as you might guess when talking about the Sunny 16 Rule, is f/16.

Note: Once the correct exposure is formulated you can change this to any combination of shutter speeds and apertures, but for this exercise, stick to f/16.

Once the lens is set to f/16, we now have to establish the correct shutter speed, which on a clear sunny day should correspond to your working ISO speed. What this means is if you’re shooting a landscape or a portrait of your cocker spaniel, for that matter, on a sunny day with your camera’s ISO set to 100, the correct exposure should be f/16 @ 1/100-second. Similarly, if your ISO is 400 or 4000, the shutter speed should be 1/400- or 1/4000-second respectively. Easy… no?

The thinking part comes into play when it’s not a bright, sunny day, and here too we’re not talking rocket science. If you’re shooting on a hazy day, open up a half stop to f/11.5. Cloudy? Open up a full stop to f/11. Light rain? Open another half stop to f/8.5, which is a stop and a half wider than the base f/16 we use on sunnier days. And if it’s pouring cats and dogs or the skies are heavy overcast, open up a full 2 stops to f/8 and you’re good to go.

The opposite of urban haze, clouds, rain and snow are sunny days at the shore, snow-capped landscapes and higher altitudes, each of which tends to be brighter due to the reflective qualities of sand, water, snow and the thinner atmospheric qualities of high altitude mountaintops. In these cases, instead of f/16, set your lens an additional stop smaller to f/22. If your lens doesn’t stop down further than f/16, simply bump your shutter to the next faster shutter speed, which from an exposure standpoint, is effectively the same.

Now for those of you aching to know if it’s possible to use apertures other than f/16, rest assured, you certainly can. F/16 is merely the designated starting point, partly because the “Sunny 5.6 Rule” doesn’t have quite the same ring to it, and more importantly, decimal points tend to confuse we “creative” types.

As for the best combination of f/stop and aperture, your final choice should be determined by the nature of the photograph you’re capturing, i.e. a landscape, sporting event, portrait, etc. That said, an exposure setting of f/16 @ 1/100-second can be easily converted to f/22 @ 1/50, f/8 @ 1/400, or f/2 @ 1/6400-second. The depth of field and blur of moving objects within the frame will vary, but the exposure density of each of these exposure variations of the original f/16 formula will remain identical regardless of your final choice of f/stop and shutter speed settings.



Just linked to this, as it is a very good explanation.

I shot only Sunny 16 for decades using the same instructions inside boxes of KODAK film. Too bad KODAK saved a bit and removed the instructions.

I still use  Sunny 16 first, then meter.

Thank you! Good thing you knew about the Sunny 16 rule before Kodak decide to become more conservative with its packaging typography!

I think what Drew was getting at is that f/8.5 (as an f/stop) is not a half stop between f/8 and f/11 rather, it would be f/9.5.  Although, I think the OP is super old school and is used to using analog cameras (why else would you need this rule? - digital cameras have a meter built inside).  On older film cameras (as in 100% analog), you would only see the full stops f/8 and then f/11.  If you wanted to get a half stop you had to eyeball it.  You would turn the dial to about half way between f/8 and f/11.  Hence f/8 (plus a half) "f/8.5".  

Also, those who used light meters will remember that the standard representation was to use a decimal.  f/8.9 would mean f/8 + 90% of another stop.  I see this miscalculation with younger photogs when reading a meter, many think f/8.9 is only less than a third over f/8 when it is in fact just shy of f/11.

Ya, well that is all... I know this post is a million years old, but hey, COVID-19 means photogs have very little else to do!  :)

Thank you for this nice historical background.
I feel like there is one item missing - the focal length this is based on, as the aperture is in units of the focal length, i.e. it describes a different opening pupil size at 50mm than it does at 135mm. I presume this is historically for a normal lens, i.e. a 50?

I'm curious because where I come from, people rhyme "sun is laughing, aperture eight". That rule is clearly based on different film stock, shutter speed, or focal length. :)

Incidentally, stops are in multiples of the square root of 2, so half stops are in multiples of the fourth root of 2 (i.e. the square root of the square root of 2). That means the half stop progression goes like

8 - 9.5 - 11(.3) - 13.5 - 16

rather than 8.5 and 11.5 as you named them. We all understand what you mean of course, hope this helps!

Hi Drew,

The Sunny 16 rule holds true regardless of focal length and/or imaging format. I've been using the formula for years and it's pretty much foolproof.

And many thanks for your feedback.



If I'm not mistaken, the "f"stop number is (roughly) the diameter of the opening divided into the focal length of the lens.  So an f16 on a 200mm lens would be a different size opening compared to an f16 on a 50mm lens. It would be a smaller opening on the 50mm compared to the larger size of the f16 opening on the 200mm. That's what allows sunny 16 to apply to different focal lengths.  

All true Andrew, and at the end of the day f/16 is simply f/16 when it comes to figuring out the correct exposure.


Great information on easy to remember language. I always like to brush up a nit before taking my Yashika Mat 124 off the shelf.

Thanks for this explanation. My friend and I were just talking about this. You made it simple for me.

Simple is a beautiful thing... no?

Glad you found my article to be of value and thanks for your feedback - we appreciate it.



This is the worst sunny sixteen page ever + but liked the bad man

Another Digital Camera person thinking again. Nothing good to say go stick your head in mud

Thanks for your info shooting better using the sunny 16, have fun shooting.


When your camera's Apeture only goes from 1.8 to 8.0  , where would the Sweet 16 rule take effect. Neither of my cameras , G15 and SX50 go to a 16 Apeture. 

Thanks for the short and sweet article.

On a sunny day how can I get a shot with shallow depth of field (f/2.8) if I don't want to increse my ISO to 3200(avoiding noise in my photo)?


You definitely wouldn’t want to increase your ISO, as that will make the sensor more sensitive to light, causing over exposure in bright situations.  So, you would want to use your camera’s lowest native ISO.  You then have two options: shutter speed and ND filters.  The wider you want your aperture in bright light, the faster your shutter speed will need to be.  Now, if you don’t want to use extremely fast shutter speeds, you can also look into Neutral Density filters.  They would cut down on the amount of light that gets through the lens, allowing you to use larger apertures and/or slower shutter speeds in bright light.  You can read a bit more about ND filters In the Filters for Lenses article on Explora.

Thanks for this explanation of a timeless concept.  The only confusion I find is that my cameras' shutter speeds don't have a corresponding 1/50 of a second and some other shutter speeds mentioned in the article.  I recognize those fractions maintain a mathematicalr ealtionship, but they don't exist on my dials. Any clarifications that you might add?  Nevertheless, thanks.

In situations such as yours, where the shutterspeeds may not be conventional or the same as those explained, you would simply use the shutterspeed closest to that by rounding up/down.  From there you can decide if you want to adjust it up or down by a stop so as to get the best exposure (or account for over/under exposure).  Testing this out in the field is recommended, this way you know on future shoots how the camera will behave.

If you're using a camera that only has standard shutter speeds, you should typically round down.  For example, using ISO 400 with a camera that has shutter speeds 250 and 500, use 250. With a normal scene (or high key, ex. snow or sand) it's better to overexpose a little bit than to underexpose.  The exception is a low-key scene, in which you would round up to overexpose slightly, so 500 would be best for dark, shadowy scenes.

It's my understanding that 1/500 lets  in half the light compared to 1/250.

Yes, for example if you're at 1/500 of a second, you can double the amount of light by going to 1/250. The flipside, if you're at 1/500 you can cut the light in half by going to 1/1000. If your camera's meter is set to 1/3 stop increments, then three clicks in either direction is one stop of light doubled or halved.

How do you find our ISO on a Olympus camera or Nikon?

It very much depends on the particular model.  If you could let us know which particular model camera from both companies, we can then specify how to find and adjust the ISO of the camera.

I am assuming you are using a 50mm, or equivalent, lens at a minimum. I've read that the shutter speed should correspond to the focal length of the lens; e.g., 150mm - shutter 1/150; 70mm - shutter 1/70, etc. Or am I missing something here?

Good observation--but then if you need shutter speed of 1/200 sec, then adjust the ISO to 200. Or if you need 1/400 sec., adjust the ISO to 400 etc. This is how I understood the article.

I think the focal length "rule" is a recommendation for a minimum shutter speed for hand held photography. Dereasing the chance a getting blurry shots because of camera shake. That said, using the sunny 16 rule, if you are zoomed in to 200mm then you should bump your ISO to 200 as you will want to shoot 1/200 sec (f16). I hope that helps.

What an awesome explanation for sunny days etc. No one could have said better. Thank you.