Master the Sunny 16 Rule!

Guess Correct Exposures in Any Weather/Indoors Without a Light Meter

18 min read by Dmitri.
Published on February 21, 2024. Updated on July 4, 2024.

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This course will teach you how to get a correct exposure without a light meter in all weather, indoors, shaded, artificially lit, and sunlit scenes. This material goes far and beyond the not-so-helpful exposure tables.

Shooting film without a light meter is a helpful exercise for everyone’s photographic practice. Understanding subtle changes in light and their effects on exposure is useful for film selection, precise metering, and a deeper connection with manual film cameras.

Unfortunately, most of us don’t trust ourselves to shoot film without the fiddly devices or phone apps that take up space and time to start up. But it doesn’t have to be this way.

The Sunny 16 rule can get you a perfect exposure in full sun. This course will help you extend this rule to all practical light conditions (including unique cases in cloudy/dark climates). It will give you the confidence to leave your light meter behind.

Learning this skill will take some persistence. This course includes a few effective, low-effort exercises that’ll get you to your first photoshoot without a light meter within a couple of weeks (or days). Following that, you’ll learn to shoot all kinds of film and cameras without a light meter.

I’ve shot expensive film stocks, medium format film, and instant film in experimental cameras using the methods described in this course. My exposure accuracy is comparable to or better than a selenium light meter (depending on lighting conditions). Your success rate will depend on many factors, but I can guarantee it’ll be better than average after going through this course. Course chapters: Who is this course for? What to expect from this course. Learning format. Prerequisites. What is the Sunny 16 rule? Why doesn’t Sunny 16 always work? The method. Good to know: exposure values. The Sunny 16 exposure indexing system. Learning to see changes in brightness like a light meter. Practice with film. Review & repeat. Tips for improving your accuracy. Identifying risky scenes. How to use this new skill to broadly improve your photography. Support this blog & get premium features with GOLD memberships!

Who is this course for?

Anyone who likes to shoot vintage (and modern) manual film cameras can appreciate the ability to shoot without a light meter. Film (motion picture) students and professionals will also find this course useful — but it’s best learned with a still film camera.

To learn this skill, you’ll need time to practice and be willing to make some mistakes while shooting film.

If you’ve been shooting film for a while, you’ll be on a fast track. But this course includes resources for photographers of all levels (see: prerequisites).

This course isn’t meant to replace your light meter — unless you want it to.

What to expect from this course.

This course will teach you how to get a correct exposure without a light meter in all weather, indoors, shaded, artificially lit, and sunlit scenes. This material goes far and beyond the not-so-helpful exposure tables.

It will not take you long to read through all the course materials. However, you will need to practice the concepts, which may take a few weeks to complete. The practice steps aren’t very technical or laborious — you can do them casually as part of your regular film photography flow.

The more you practice using the methods in this course, the better you’ll be at reading the light. You may still make mistakes, but you’ll know when they will most likely happen.

Learning format.

This course is an illustrated text guide. It’s written for photographers of all levels. All advanced concepts have links to explainers on this website or elsewhere.

This course is updated regularly based on your feedback. You can ask questions in the comments, and I will answer them.

Prerequisites.

Tools. All you need is a working manual film camera, a few rolls of film, and a smartphone.

Skills. You need to know how to shoot a manual film camera. If you don’t, please read “A Beginners Guide to Manual Film Cameras” first. It’s a popular free resource that you can also download as a printable PDF.

You’ll also need to be familiar with exposure values, explained in this guide and understand what exposure means in photography.

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Shot on Fujifilm Fuji Pro 400H with Mamiya RZ67 Professional II — without a lightmeter.

What is the Sunny 16 rule?

☀️ The Sunny 16 rule says:

Set your aperture to 𝒇16 and shutter to the film’s ~ISO*, and you’ll get a correct exposure in full sun.

It’s a rule because it’s always true — as long as you are photographing a scene lit by unobstructed sunlight, it will have an optimal amount of exposure with those settings.

✱ — Shutter speeds won’t always match your film’s ISO exactly, but that’s OK. For example, for an ISO 100 film, you can set your shutter to 125; ISO 400 matches 500; ISO 800 matches 1000, etc.

Note that shutter speeds are often marked as whole numbers on cameras; in reality, they are fractions of a second (e.x., 1/125, 1/500). In this course, I use fractions and whole numbers interchangeably.

Why doesn’t Sunny 16 always work?

There are exceptions to the Sunny 16 rule. Snow is very bright, especially at high elevations; thus, 𝒇22 may be a more appropriate aperture. The sun also needs to be high up; the Sunny 16 rule does not work reliably during the sunset and sunrise and can not be obstructed by clouds, smoke, fog, or haze. The Sunny 16 does not apply under any type of shade or indoor lighting.

This tutorial explains how you can “extend” the Sunny 16 rule to apply to all of the above conditions with a bit of technique and practice.

The method.

The process of reading the light without a light meter is simple:

Recall a scene from memory that matches the current one best and use the associated exposure value to set your shutter speed and aperture.

You’ll use the Sunny 16 rule as a basis for your shutter speed and aperture calculations.

But before you can do that, you’ll need to commit as many variously-lit scenes to memory as you can. You’ll also need a system to index those scenes and a way to translate what you remember to correct camera settings quickly.

Don’t worry, you don’t need an amazing memory (I surely don’t have that). There are ways to train yourself without strain.

Good to know: exposure values.

Exposure values (EV₁₀₀) are the standard units for measuring the brightness of ambient light in photography.

A Beginners Guide to Manual Film Cameras explains how cameras’ apertures and shutter speeds work together.

Exposure values index the measured portions of light transmitted onto film in stops. When an ISO 100 film receives an optimal amount of light through an 𝒇1.0 aperture with a 1sec. shutter speed, the exposure value (EV₁₀₀) is 0.

Because the film sensitivity (ISO) is fixed, the EV₁₀₀ of 0 corresponds to a specific ambient light intensity (which happens to be very dark).

In full sun, when the Sunny 16 rule says we should use an aperture of 𝒇16 and a shutter speed of 1/125s with ISO 100 film, EV₁₀₀ is 15.

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12 stops of exposure with Kosmo Foto Mono (ISO 100) and Vitessa A.

The Sunny 16 exposure indexing system.

The EV₁₀₀ units were developed for photographers as an alternative to the luminous exposure to understand the ambient light using familiar tools: aperture, shutter speeds, film ISO, and stops.

However, EV₁₀₀ units are too clumsy for what we’re trying to do here. “Sunny 16” is just so much easier to say, remember, and translate to camera settings than EV₁₀₀ 15.

So here’s a better way to measure light for our purposes:

[Sunny 16] is a sunlit scene, as the rule describes.

[Sunny 16 -1] is one stop darker (e.x., a slight haze but plenty of light).

[Sunny 16 -2] is two stops darker (e.x., a thin cloud is covering the sun).

Etc.

It’s much easier to identify how many shades the light is darker than that of a bright sun than trying to figure out what EV₁₀₀ unit the illumination corresponds to. It’s also easier to slow down the shutter speed by -1 stop for [Sunny 16 -1] than to translate EV₁₀₀ 14 into practical camera settings.

Here’s how this system can be applied in practice:

1) Identify how much darker your scene is than full sun/Sunny 16.

Suppose you’re in a shade that’s five stops darker. (I’ll explain below how you can tell how many stops the shade is darker than in full sun.)

2) Adjust your camera settings accordingly.

Let’s say you’re shooting with an ISO 100 film. In full sun, you’d set your aperture to 𝒇16 and shutter to 125. But since the actual light is five stops darker, you’ll need to open up your aperture to 𝒇2.8 for a correct exposure.

Typical lens apertures progress in full stops as follows (from widest to smallest, where smaller numbers mean wider apertures/more light entering the camera): 𝒇1.4, 𝒇2, 𝒇2.8, 𝒇4, 𝒇5.6, 𝒇8, 𝒇11, 𝒇16, 𝒇22.

You are, of course, free to change those settings as long as the exposure (amount of light transmitted onto film) remains the same. For example, if you’d rather shoot at 𝒇8 (which lets in three stops less of light than 𝒇2.8), you can do that with the 1/15s shutter setting (which lets in three more stops of light than the 1/125s).

There are various reasons you’d want to shoot at 𝒇8 rather than 𝒇2.8 that are beyond the scope of this article. But you may want to set your shutter above 1/60s for most scenes/cameras to avoid motion blur when shooting without a tripod.

If you’d like to make the above calculations in your head, you’ll need to get familiar with the aperture and shutter speed progressions. However, your manual film camera will have those numbers marked in sequence: rotate the aperture ring to a smaller number to let in more light or slow down your shutter by setting it to a smaller number. The articles mentioned in the prerequisites (above) should help you understand how to do this right.

You can also use the Sunny 16 Calculator tool I built to help estimate shutter speeds and apertures for 13 common light conditions.

💪 Exercise 1: Get familiar with various lighting conditions using the Sunny 16 Calculator tool and how they affect your aperture and shutter speed for a given ISO. Try selecting different film speeds and see how that affects your shutter speed and ISOs; cycle through various lighting conditions to see how that affects your camera settings.

Learning to see changes in brightness like a light meter.

There’s plenty of literature out there that suggests camera settings for select weather conditions. However, those exposure guides or exposure tables are typically incomplete and come with misleading illustrations/light descriptions.

Exposure guide from the package of ORWO NP 20 film.

For example, it’s easy to misinterpret a sky full of clouds as “cloudy weather ⛅️” while the sun may be shining in full force (i.e., the clouds are everywhere but not obstructing the sun). Moreover, clouds and haze vary greatly in their effect on the sun — from none to -9 stops of exposure.

A better way to learn correct exposures for various lighting conditions is to actively observe, measure, and memorize situations relevant to you and your environment. Together with the Sunny 16 exposure indexing system, you can use that knowledge to make accurate exposures with your manual film camera without a light meter.

💪 Exercise 2:

1) Download the free Lumu light meter app for your mobile device. Any light meter app with a spot metering function will work. You can also use a physical light meter. Mobile apps have live previews, which is preferable for these exercises. I don’t recommend using selenium light meters for these exercises.

2a) Take your light meter with you everywhere you go, especially places where you expect to take pictures. Lock your light meter to ISO 100 and 1/125 shutter speed and observe the aperture values it returns. Refer to the aperture scale to determine how many stops the scene is below the optimal Sunny 16 (𝒇16). 𝒇11 is one stop below, 𝒇8 is two stops below, 𝒇5.6 is three stops, etc.

Your objective is to learn how various shadows and artificial lighting sources affect the exposure. Converting your light meter’s values to the Sunny 16 exposures will take some mental energy, but it’s worth the effort.

2b) Use a spot meter to point your light meter at the pavement and compare that with the value your LM returns under sligh/dark shadows and various weather. Make a mental note of how many stops darker those conditions make the pavement.

Keep in mind that darker-colour objects may force your light meter to give you different readings than light-colour objects in the same light. Wet pavement will be darker than dry pavement. Also, beware of backlit scenes.

Use the spot meter to learn proper exposures for select parts of the scene. For example, you may want to optimize your exposure to well-lit parts of a city at night.

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Sunny 16 -10 or 10 stops darker than a full-sun exposure: this photo was taken on CineStill 800T with Voigtländer Vitessa A at 1/125s with 𝒇2 aperture. Note how the middle white taxi has the optimal exposure, while the lights are allowed to over-expose and the shaded areas are under-exposed.

2c) Use the average meter value (non-spot metering) and observe how the light changes in scenes with uneven/mixed lighting. Examples: under a tree in sunny weather, during sunset and sunrize when there are a lot of shadows in the open, and inside your home on a sunny day in various rooms/close/far away from the window.

Beware of the rapidly changing light during sunrises, sunsets, and indoors.

3) Try guessing the exposure and then verify with your light meter. Keep doing that until you’re able to guess within one stop of the “correct” exposure at least half of the time.

Remember, you’ll be guessing using the Sunny 16 index. For example, a shaded area under a tree, according to your guess, may be -3 stops darker than sunlit areas.

It will be easier to guess during the sunny weather as your brain can use it as a reference and then recall memorized scenes in relation to the sunlight. In unfamiliar settings or weather, I suggest you take a measurement with your light meter first and guess after.

Lumu light meter recommends an aperture of 𝒇4.0 for a shutter speed of 1/250s and an ISO 400 film. This is equivalent to 𝒇2.8 with 1/500s, which is 5 stops darker than a fully sunlit scene (Sunny 16 -5).

4) Practice using the Sunny 16 exposure indexing system . Once you get comfortable converting your light meter’s readings to the Sunny 16 values (i.e. ISO 100 and 1/125 with 𝒇8 is Sunny 16 -2), you’ll need to learn how to convert the Sunny 16 scale into camera settings. Thankfully, it’s easy to do — which is useful as you don’t want to make mistakes when you’re shooting with film.

For example, once you guess that your scene calls for -2 stops, you’ll know that you’ll need to adjust your aperture by two stops (to 𝒇8 from 𝒇16).

You may also want to practice making those conversions with various shutter speeds and film ISOs. Use the Sunny 16 Calculator to help make those determinations.

The Sunny 16 Calculator shows an image next to each exposure value. Your mind should organize your own images next to each exposure, perhaps more than one per exposure.

Everyone learns differently. I didn’t record guesses and observations during those exercises, but it may help you.

🫵 Don’t get discouraged by wrong guesses or the complexity of calculations! The skill you’re learning takes time to acquire, but it’s useful to all kinds of photography and beyond.

Practice with film.

Once you can comfortably guess your light within 1-2 stops of your light meter’s output, you’re ready to start practicing with film. However, not all film is a good practice material.

The price isn’t the only consideration. Your film should have a wide dynamic range, which should make it a forgiving medium.

For black-and-white film, Fomapan 100/Kosmo Foto Mono, Ilford HP5+, and Kodak Tri-X are excellent candidates. All of these emulsions are relatively forgiving of exposure mistakes. Fomapan is known to be the cheapest film on the market.

Kodak Portra 800 and CineStill 800T (or an alternative) are high-speed wide dynamic range films that are forgiving but expensive. If that’s too much, you can try Kodak ColorPlus (the cheapest colour film) or Kodak Gold.

Aside from price and colour, you should consider the ISO that’s most appropriate for you. Naturally, higher ISOs are more appropriate for darker scenes. Please also note that not all labs can develop black-and-white film.

Please also note that all the film options above are for negative film. This means that you’ll get better results if you over-expose them than under-expose. I noticed that in unfamiliar, dark settings, I tend to guess there’s more light than actual; to compensate, I add a stop or two to my guesses — you’ll learn how your guesses skew by observing your results from the developed film.

I’m not diligent enough to take notes on every shot taken, but that could be helpful to you when you examine your results. You may want to note which frames you took without a light meter and the camera settings or the Sunny 16 index value (i.e., Sunny 16 -5).

One last thing: not every shot on your designated roll of film has to be measured by eye. Feel free to mix your techniques — just make sure to note which shots were metered by eye.

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Shot on Kodak Aerochrome with Voigtländer Vitessa A — without a light meter.

Review & repeat.

Examine the frames you took without a light meter. Try to remember or refer back to your notes about your guesses. Take note of the mistakes and successes.

Your notes or recollection of your shots should help you see how you can do better with the next roll. If you’ve practiced well with the light meter, you may find that your eyeballed exposures are nearly or as precise.

Light meters are not perfect. Thus, I wouldn’t expect automatic exposures to be more “accurate” by definition. Instead, your goal should be getting exposures that match your intentions.

You may also want to examine your negatives’ density. Though beyond the scope of this tutorial, film density can help you understand the quality of your exposures and film development without the bias of scanning software which may be hiding exposure mistakes.

Tips for improving your accuracy.

If you’re about to shoot film in an unfamiliar light, pull out your light meter and take a few readings — especially the brightest and the darkest spots. This will help you “calibrate” your eye.

Artificially-lit interiors can be tricky, and so is unfamiliar² weather — whether it’s the change in the season or if you’re travelling, it’s good to “calibrate.”

If you haven’t metered light by eye for a few days, you may want to refresh your memory with a light meter before pulling out your camera.

If your film has an ISO higher than your fastest shutter speed (for example, Kodak T-Max P3200), get familiar with possible camera settings and Sunny 16 index values using the Sunny 16 Calculator app ahead of time. Memorize a couple of key settings to avoid having to do complex arithmetic in the field.

As the years pass and you practice this method more, you’ll need your light meter less; your confidence and your accuracy will grow.

Some films, shutter speeds, and apertures are marked in fractions of a stop. For example, Kodak Portra 160 is ISO 100 + ⅔ of a stop. You may like to round those values in your calculations while keeping in mind that negative film will handle over-exposure better (thus, shooting Portra 160 as if it was an ISO 100 film may yield better results than if it was shot at EI¹ 200). The opposite is true for slide films; thus, for example, you can treat 𝒇3.5 aperture as if it was 𝒇2.8.

Getting exposure off by a half or a third of a stop wrong is rarely consequential to the quality of your images. However, it still helps to round in the direction that’s beneficial to your type of emulsion.

As mentioned above, consider picking stocks with a wide dynamic range. If you must shoot slide film without a light meter, try Kodak Ektachrome E100 first.

¹ — EI stands for Exposure Index, which in this case means an assumed ISO value. EI is different from an ISO since the latter is a manufacturer-set constant, whereas EI can be any number.

² — Unfamiliar weather refers to conditions during which you haven’t yet practiced with a light meter.

Identifying risky scenes.

Film is not cheap, and time always moves forward.

A fast-paced environment, where the light changes rapidly, makes guestimating exposures very difficult. For example, if you’re photographing wildlife as it flocks from sun to shade, it may be easier to use a camera with automatic exposure settings.

Sunsets and sunrises can be tricky. The light changes rapidly and the environment is usually filled with long shadows and sunlit spots. You can still use the methods described in this guide; consider spending an extra few days with a light meter studying how the light changes ahead of time.

If you plan to be distracted, for example, at a party with lots of people and variable light sources, a point-and-shoot camera may give you more “keepers.”

If you’re shooting slide (reversal) film, low dynamic range film, or expired film, understand that your guesses must be more accurate to be successful.

How to use this new skill to broadly improve your photography.

As you learn to guess exposures, you’ll also begin to identify contrast ratios in your scene. A contrast ratio is the difference between the brightest and the darkest spot in your frame in stops. This can help you select appropriate film stocks (i.e., low dynamic range films for low contrast ratios — e.x., foggy weather — and high dynamic range for high contrast ratios — e.x., brightly lit objects with harsh shadows).

You may also visualize dynamic range better — a key piece of data film manufacturers publish when they release new film. You’ll know when to take film with five stops of dynamic range and when 12 stops would be more appropriate. See “How to Make Perfect Exposures on Film” for more.

In full sun, you can calibrate your old light meter or a camera; evidently, older (especially selenium) light meters tend to over-expose in such light. You will also instantly know when a point-and-shoot camera is broken.

Knowing how to estimate exposure by eye helped me understand film and cameras better than I ever could without it. I am more confident with manual rangefinders and SLRs than ever before. I hope that this tutorial will help you to achieve the same.

Please feel free to ask any questions, add requests, and post your comments below. I check messages daily.