Understanding how aperture works will affect the success of any person or company that relies heavily on photography to communicate to its audience. It is important to understand the full scope of aperture, rather than being told to use specific settings and being restricted by those settings. Knowing how aperture works will allow a photographer to problem solve and experiment while shooting.
Every lens has a series of numbers, or ratings, called F-stops. These numbers are settings that measure aperture and therefore describe the amount of light being funneled to the camera.
At first glance, the numbering system used to measure aperture may seem backwards. The lower the number (like “F2,” “F1.8,” etc), the larger the opening and the more light may pass through to the camera. The higher the number (like “F16,” “F22,” etc.), the smaller the opening and the less light passes through.
With a lower number F-stop, photographers are able to have a faster shutter speed because there is more light. Shutter speed is the quickness of the opening and closing of the shutter in the camera, behind the lens. The shutter functions just like shutters for a window, only it is either all the way open or closed. The length of time the shutter is open is the length of time it takes to capture an image. The faster the shutter speed, the a faster an image is created and the less time there is to blur a subject. This is highly beneficial for low light situations.
Aesthetically, a lower number F-stop creates a shallow depth of field or selective focus, meaning focus falls off and blurs around one focal point. This concept is great for portraiture and photojournalism, among other situations, because it allows the photographer to draw specific attention to one element of an image. For example, a portrait of a woman who is smiling with her mouth closed; there is no need to focus on her entire face, just her eyes. Everything else can fall out of focus.
The impact and clarity of her eyes will be the main focus of the image and say everything that needs to be said: she’s happy.
If an object is being photographed in a cluttered situation, a low aperture allows the photographer to focus attention where desired. In the example below, the viewer will automatically focus on the martini.
On the opposite end of aperture, the higher the F-stop number the less light is being allowed through the lens to the camera. This means the opening is smaller and the shutter speed will be slower due to the need for more light to capture an image at a correct exposure.
You might think that if it is going to take longer you should use the smaller number F-stop for product photography. However, the depth of field is reversed in this scenario. There is a specific reason to use a higher F-stop; the focal point carries through the entire image, rather than falling off (Deep Depth of Field). The longer an image is exposed with a higher number F-stop, the more the image will be in focus. This practice is ideal for the majority of product photography, especially for products on a nondescript background.
In most circumstances, especially on category pages, you want the entire product image to be in focus like the F-stop 16 sunglasses example below. On rare occasions, like when directing a user to a specific zoomed in detail on a product, a low aperture may be advisable.
There are a few factors a photographer needs to consider when determining what F-stop and shutter speed settings are appropriate for specific goals. Product photography settings are dependent on lighting, whether or not you have a moving subject in addition to the product (like a model), and tripod usage.
First, it is almost always preferable to use a tripod in product photography. Even the slightest movement by a photographer hand-holding a camera can prevent capturing a perfectly clear image, especially with a longer exposure time. You need full focus to show every detail and make the product tangible to the customer. Additionally, using a tripod will ensure consistency in the perspective of the product photographs and allow for an efficient hands-free workflow.
Second, the light source must be considered. If it is a continuous light source, whether ambient sunlight or an artificial light, the light is usually less intense. The need for more light will require a longer exposure time. Now you must set the necessary aperture for full focus: as a rule, F16 to F22 will give full focus. Once the F-stop is set, adjust the shutter speed around it with a goal of perfect exposure.
Finally, you will need to make adjustments if a model or moving subject is being used. If there is, all camera settings will need to be adjusted depending on the kind and pace of movement. A normally paced motion can be captured clearly, at best, around a shutter speed of 1/250 of a second or higher. Slower motion can usually be captured at a shutter speed of 1/125 of a second. These numbers can change depending on the specifics of the camera hold, tripod usage, ISO, and experience.
When using high-intensity artificial lighting, like strobes, F16 at 1/125 of a second with a slow to normal moving subject is almost always accurate. You should experiment and learn the ideal settings and limitations of this type of lighting prior to shooting your product; models are expensive! It’s also worthwhile to educate yourself on camera ISO and practice hand holding at different shutter speeds. Once the basics are learned and practiced, it will become second nature during a shoot.
There are an abundance of elements, both technical and environmental, that can affect the capture of an image. Out of the many, aperture emerges as a defining factor. Why? Because focus is essential for communicating as much truth in product images as possible. Truth creates trust, and trust sells products.