I tried to use the "Sunny 16 rule" but it didn't work, why?

Question

In a sunny day, I tried to apply the Sunny 16 rule to the following scene:

f/16, ISO 100, Shutter Speed: 1/100

and ended up with a dark image. Then I tried another shot with another settings which yielded the following result:

f/16, ISO 100, Shutter Speed: 1/30

The second image is a little over-exposed, but in my opinion is better than the first one. Why have I failed to capture a good picture following the Sunny 16 rule?

Answer 1

The "Sunny Sixteen" rule applies to things that are lit by the sun. In the picture you took using the rule, things which are lit directly by the sun are well-exposed i.e. the cut-off tops of the branches, as well as their sunlit side, and the sunlit areas of the nest.

The leaves are a bit of a problem, since they are relatively waxy; the parts of the leaves that would be green are also shadowed, or at least being lit from a very steep angle, and the parts that are receiving a lot of direct light are also giving you specular reflection from the leaves' protective coating. (You can reduce or eliminate that blue/white reflection using a polarizing filter, leaving you a brighter green from the leaf beneath.)

It looks like that you wanted a picture of the nest, which is mostly in shadow. (And yes, your second picture, the one taken at 1/30s, is quite overexposed, but is probably recoverable if you have the raw file.)

So it's not that "Sunny Sixteen" failed. You were simply trying to take a picture where "Sunny Sixteen" didn't apply, since the subject wasn't fully sunlit. Most of the light was coming from the sky/reflections, not directly from the sun.

Answer 2

I have to be honest, I think the first is better. It's darker, sure, but that's probably more the JPEG conversion settings in the camera than anything. From my perspective, I think you could do a lot more with the first image using RAW data and maybe a marginal lift in exposure. Point is, you didn't clip the highlights with that and it gives you room to work that is lost in the second image.

In any event, the thing to remember is that the "Sunny 16" rule is a rule of thumb for bright daylight and film, sensors aren't actually film and there's always a little variance. It's not uncommon for ISO setting on the camera to not exactly match ISO for film (DxOMark tests that) and, in the case you have here, ISO 100 setting may actually really be a touch less on the sensor in comparison to film. So, knowing that, in the future you just make a slight adjustment to your settings to compensate (e.g. use exposure compensation) if needed. Better yet, shoot RAW and take care of it when converting after the fact.

Answer 3

I think you have a worse problem than the "failure" of Sunny 16 (as user32334 said, it doesn't apply here)--given the light conditions I don't think that nest can be properly exposed with any settings--there's too much difference between the lit portion and the portion in shadow.

I strongly suspect the only way you're getting a good shot is to shade the whole thing and increase the exposure accordingly.

Answer 4

The sunny 16 rule captures a sunlit scene accurately. It doesn't necessarily capture it as you perceive it or intend it. For example, you can use the sunny 16 rule to take photos of the moon, because it is a sunlit object. But it will appear dark gray, which is in fact its true color. We generally perceive the moon to be brighter, almost white, because we're used to seeing it at night against a dark background. So to get a photo of the moon as you perceive it, you'd start with the sunny 16 rule and then open it up an extra stop or two.

Answer 5

The sunlight in the scene is coming from right. So it is not f/16 but f/11 (f/16 only when sunlight is direct behind you and in front of you subject).

So: f/11, ISO 100, Shutter Speed: 1/100 or: f/16, ISO 100, Shutter Speed: 1/50

Both exposures are more correct and closer to your automatic!

Answer 6

Sunny 16 assumes that the ISO is 100. With film (when this rule came about) that worked because the dynamic range of the film people were shooting (print) was sufficient to capture the scene when they lacked a camera that had a light meter in it. Even then people would sometimes tweak their exposures (shooting Velvia 50 at 80). Those who were really into it didn't even trust the label and would buy a brick of film, shoot one roll for standardized tests and stick the rest of it in the freezer (keeping note of the batch number) so that they can develop it perfectly for what its actual ISO and conditions where. Others would just do a clip test on each roll.

There are no digital cameras that lack a light meter (that I'm aware of at least). That brings us to the ISO sensitivity of the sensor. Going from DxO for the Canon 650D, its actually fairly accurate:

Other cameras can be less accurate (related article: ISO Lies: When ISO 100 is really 72:

_{(source: adorama.com)}

This (not yours) camera is almost a full stop stop slower than what its ISO claims. If you tried shooting the Sunny 16 with that camera, you'd be getting underexposed images consistently.

Next, the Sunny 16 is just a ballpark estimate. Unless you know exactly what the amount of light and what you want to expose for you are getting (varies with latitude and time of day quite substantially), you can be off. Not everyone knows that the full moon is 250 c/ft² or how to translate that into the proper exposure.

Abiding with the Sunny 16 only is for those people who are trying to take a photo with a holga (you have 1/100 or 1/125 for shutter speed and f/8 or maybe f/11 for the aperture) and need to pick the right film to load in the camera (is it cloudy? sunny? indoors?).

For everyone else, if you've got a light meter, use it. Ballpark estimates are for when you aren't sure and just want a photo in the ballpark. Its better to be sure if you can be.

In your case, Sunny 16 didn't fail. It captured an image that was not completely illuminated by the noon sun (it was in the shade). It captured the leaves quite acceptably, though the subject that you were really after is completely in the shade.

Some random advice for the scene:

• Put a polarizer on the lens. This will cut down the reflections from nonmetallic surfaces (such as leaves) allowing you to capture the green of the leaves rather than the silver of the reflected sun. It also cuts down the necessary dynamic range.
• Use the 'partial' metering mode (9% at the center) or center weighted and compose the image the same as you did (with the nest at the center) (see page 115 of the manual for metering modes). This lets the camera know what you are interested in actually photographing and exposing properly.

I'll also point out that I prefer the first photograph over the second.