Why f/16 Used to Be Recommended:
* Maximize Depth of Field (DOF): The primary reason for using smaller apertures like f/16 is to increase the depth of field, ensuring that both foreground and background elements are sharp. In the film era, and with older lenses, f/16 was often the sweet spot for maximizing DOF without significant image quality degradation.
Why f/16 is NOT Always Best (and Often a Bad Idea):
* Diffraction: This is the biggest problem. As you narrow the aperture opening (increase the f-number), light waves bend and interfere with each other as they pass through the tiny hole. This causes a *softening* of the entire image, reducing sharpness and detail. The smaller the aperture, the worse the diffraction. On many modern lenses, diffraction becomes noticeable at f/11 and is quite significant at f/16 or f/22. You're essentially trading sharpness for depth of field, and often sharpness is more important.
* Sensor Size Matters: The impact of diffraction is more pronounced on cameras with smaller sensors (e.g., smartphones, Micro Four Thirds) than on cameras with larger sensors (e.g., full-frame). You'll likely see diffraction ruining your image at f/11 on a Micro Four Thirds camera, while it might be acceptable on a full-frame sensor (though still present).
* Light Requirements: Using a smaller aperture like f/16 reduces the amount of light entering the camera. This means you'll need a slower shutter speed or higher ISO. Slower shutter speeds increase the risk of motion blur (from wind or camera shake), and higher ISO introduces more noise into the image. You may need a tripod at f/16, even in moderately bright conditions.
* Lens Quality Matters: A cheap lens will perform poorly at all apertures, and stopping down to f/16 won't magically fix its deficiencies. A high-quality lens, however, will often deliver exceptional sharpness at wider apertures like f/8 or f/11.
* Focus Stacking as an Alternative: This technique involves taking multiple photos of the same scene at different focus points and then merging them in post-processing. This allows you to achieve maximum sharpness from foreground to background without sacrificing image quality due to diffraction. You can use a wider aperture (like f/8 or f/11) and retain sharpness, while also keeping your ISO lower and your shutter speed faster.
So, What *IS* the Best Aperture for Landscape Photography?
The "best" aperture depends on a multitude of factors:
* Desired Depth of Field: How much of the scene do you need to be in focus? A sweeping vista might require more DOF than a close-up of wildflowers.
* Lens Sharpness: Find the "sweet spot" of your lens – the aperture at which it produces the sharpest images. This information can often be found in lens reviews (e.g., on sites like DXOMark or LensRentals). Typically, this is around f/5.6 to f/8, but varies by lens.
* Sensor Size: Factor in how diffraction will impact your image at different apertures.
* Lighting Conditions: How much light is available?
* Subject Matter: Are there moving elements (like water or clouds) that require a specific shutter speed?
* Desired Creative Effect: Do you want shallow depth of field to isolate a subject?
General Guidelines:
* Start with f/8 or f/11: These are often good starting points for achieving a balance between depth of field and sharpness.
* Consider f/5.6 - f/8: for situations where maximum sharpness is the primary concern, or when focus stacking.
* Only use f/16 or smaller as a last resort: When extreme depth of field is absolutely necessary and you're aware of the potential for diffraction. Consider focus stacking instead.
* Experiment: The best way to determine the optimal aperture is to experiment with your own gear and shooting style. Take test shots at different apertures and analyze the results on your computer screen.
In conclusion, the "f/16 and be there" rule is outdated and should be abandoned. Landscape photography is about making informed decisions based on the specific conditions of the scene, your equipment, and your desired outcome. Understanding the trade-offs between depth of field, sharpness, and other factors is crucial for creating stunning landscape images.