In photography, the sunny 16 rule is a method of estimating correct daylight exposures without a light meter. Apart from the advantage of independence from a light meter, the sunny 16 rule can also aid in achieving correct exposure of difficult subjects.
According to the Sunny 16 rule, simply set your aperture to F16, your shutter speed to the reciprocal of your film speed (so if you're shooting ISO 100 film, ~1/100 sec), and your exposure should be close-enough to spot on; amazing!
According to the sunny 16 rule, shutter speed is to be set to the reciprocal (or inverse) of whatever ISO is in use. Thus, in this example, the shutter speed would be 1/100. If you decided to use ISO 400, then you would set your shutter speed to 1/400.
The Sunny 16 rule states that, on sunny days, at an aperture of f/16, your shutter speed is the inverse of your ISO value. For instance, if you set your camera at an aperture of f/16 and ISO 100, your shutter speed should be 1/100 s. This is one of the easiest photography rules to remember.
Everything you need to remember about the Sunny 16 rule is in the name - if it's a sunny day with no clouds, and your aperture is at f/16, your shutter speed will be the same as the ISO value. So, if your ISO is 200, at f/16 your shutter speed will be 1/200, and if your ISO is 400, at f/16 it will be 1/400.
400 ISO film set at 800 on your camera is 1 Stop (+1) underexposure because it's doubled. But if you put 400 ISO film as 200 on your camera—that would be a 1 Stop (-1) overexposure because you halved it.
Most cameras allow you to use half a stop or even a third. So, you might see 1/160 or 1/180 and think that's the closest value to ISO 160. However, the Sunny 16 rule considers full stops. So, the closest shutter speed to 160 would be 1/250.
Simply put, the Sunny 16 Rule helps photographer read their light during the day without using a camera's meter. It was used as a cheat sheet for photographers who were shooting film and needed to meter the light without the use of technology we have today.
The Sunny 16 Rule originated in film days when cameras did not have internal light meters. In modern times, some consider this rule a relic, but it can still hold true today. The Sunny 16 Rule is based on the brightness of light only and not how that light is being reflected by the objects.
ISO camera settings for a sunny day.
Once you have your low ISO set, follow the sunny f/16 rule, or Basic Daylight Exposure (BDE), for your ideal shot. This rule determines that your lens aperture should be set to f/16, with a shutter speed of 1/your selected ISO.
The Sunny 16 rule will help you shoot without a meter and it's very accurate when done right. Set your aperture based on your conditions. Set shutter speed* to match the film iso you're shooting. *Round down if your camera doesn't have the specific shutter speed.
100 or 200 is the best ISO for a sunny day or bright setting with lots of light. 400 ISO for cloudy days or indoor shots. 800 ISO for indoors without an external light. 1600+ ISO for low light situations.
Using the Basic Sunny 16 Rule on a Sunny Day
So, if you're shooting at ISO 100, then your shutter speed would only need to be at 1/100 second for the correct exposure. If you're shooting at ISO 800, then you shutter speed should be set to 1/800s.
For outdoor the sunny 16 rule of thumb was printed. For indoors it was around 1/30 sec shutter at f/1.4 for iso 400.
The key to a great outdoor portrait is considering how bright it is outside. In full daylight, use a lower ISO setting, between 100 and 400, while later in the day or at night you'll have to pick a much higher setting. Playing around with the ISO settings can produce fantastic results — just don't go overboard.
With ISO 400 film, you can take photos indoors using light from doorways or windows. It's an excellent choice for taking portraits indoors with natural lighting. ISO 400 film can also be used outdoors in cloudy or overcast conditions.
What is the rule of thirds? The rule of thirds is a composition guideline that places your subject in the left or right third of an image, leaving the other two thirds more open.
Golden hour is a thing and the reason it's the best time of day to photograph is because the light is less harsh during sunset/sunrise than during the middle of the day. This is because the sun's rays have further to travel when they are low on the horizon.
The Sunset f/4 Rule
Change your original sunny f/16 setting to f/4, which is +4 stops. Compensate by changing your shutter speed by -4 stops to 1/3200 seconds. Doing so should result in an image that's just as well-exposed as if you used f/16, ISO 200, and a shutter speed of 1/200 seconds on a bright, sunny day.
Choose the right camera settings for a rainy day.
ISO — You'll need a medium-to-high ISO to compensate for low-light conditions on a rainy day without sacrificing shutter speeds.
During the day time in perfect sunny conditions always set your ISO to 100. This correct ISO setting is fast in these situations, even for hand held shots, which will result in the best image quality possible.
200 ISO cameras are suitable for bright daylight and well-lit indoor shots. Without a doubt, the Kodak Gold 200 is one of the best 35mm films in the 200 ISO range. If you want to shoot in low light, inside, or during the evenings, this low-speed film isn't for you.
For the most part, these machines use a less intense x-ray that is unlikely to damage film. The TSA states that film less than 800 ISO can go through the x-ray machine for carry-ons without a problem.
A low ISO film, such as 100 or 200, produces sharper images with less grain, but will require more light to capture an image. A high ISO film, such as 400 or 800, results in brighter images in low-light environments but can introduce more grain in the photo.