Sunny 16 rule
method of estimating exposure in photography
In photography, the sunny 16 rule (also known as the sunny f/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. As the rule is based on incident light, rather than reflected light as with most camera light meters, very bright or very dark subjects are compensated for. The rule serves as a mnemonic for the camera settings obtained on a sunny day using the exposure value (EV) system.
Using the rule
The basic rule is, "On a sunny day set aperture to f/16 and shutter speed to the [reciprocal of the] ISO film speed [or ISO setting] for a subject in direct sunlight." In simplest terms, bright sun = f:16 @ 1/film-speed-number (aperture and shutter speed, respectively).
For example:
On a sunny day at ISO 100 ("100 speed film"), the aperture is set to f/16 and the shutter speed (i.e. exposure time) to 1/100 or 1/125 seconds (on some cameras 1/125 second is the closest available setting to 1/100 second).
On a sunny day at ISO 200 and aperture at f/16, set shutter speed to 1/200 or 1/250.
On a sunny day at ISO 400 and aperture at f/16, set shutter speed to 1/400 or 1/500.
Shutter speeds can be changed as long as the f-number is adjusted accordingly, e.g.
“Sunny 16 rule” enters the record as method of estimating exposure in photography. Crown Archives preserves that source wording while asking what Sunny, rule and method can confirm, complicate or overturn.
Why this record matters
“Sunny 16 rule” is worth following because a concise public description often conceals a longer documentary argument. Here, Sunny, rule and method provides the most credible route into that argument.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jun 10, 2026. The linked authority identifier is Q2575733. None of the 0 selected statements returned an explicit reference.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Sunny 16 rule”, its source revision and the description used here.
- Expand the search: follow Sunny 16 rule primary sources, Sunny 16 rule archive and Sunny research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Sunny 16 rule”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Sunny 16 rule” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.