Image Clarity, Aperture, and Diffraction

At Ortery Technologies we are always looking to expand our photography knowledge and solve problems for our customers. This week we came across an excellent video by Alex Koloskov, that explains diffraction and how it plays a part in macro photography. Here is how we would explain image clarity, aperture, and diffraction.

Light travels in waves and your camera lens acts as a barrier between light and the camera sensor. When shooting at a small aperture such as f22 your lens is only allowing a small amount of light through. While this increases your overall depth of field it causes the light to travel through in more of a cone shape. As the light passes through the opening, it quickly spreads and bounces off the walls of the chamber. This causes diffraction and degrades the overall image quality. When you shoot at a large aperture like f8 there is a large opening which allows the light to easily pass through the camera lens to the camera sensor. This minimizes bouncing of the light, which leads to sharper images. Although you experience a lower depth of field, your image has a higher clarity on the areas that are in focus. This concept is illustrated in the diagram below.

aperture

Here are two sample shots that show the effects of diffraction. The first image is shot with an aperture of f8. The second image is shot with an aperture of f32.

lower_depth_of_field

Lower Depth of Field – f8

greater_depth_of_field

Higher Depth of Field – f32

While the first image has a lower depth of field, the area that is in focus is extremely clear. The second image shot at f32 has a greater depth of field, but lacks the clarity that can be seen in the first image.

At this point you might be asking yourself “how can I achieve both a high level of clarity and a large depth of field?” Ortery Technologies software has a feature called focus stacking which allows you to take multiple images and compress them into one image that is in focus from front to back. This allows you to shoot at an aperture like f8 where you will receive a low depth of field and high level of clarity. Here is an example where we shot the same amethyst with an aperture of f8, but using focus stacking. A total of 13 images were captured and processed into this final image.

focus_stacking

Understanding diffraction helps explain why using a higher f-stop value to achieve a greater depth of field is not always the best approach. We now know by doing so we are losing overall clarity from our image. The invention of focus stacking has given us the ability to use a low F-stop value to achieve a higher level of clarity and depth of field.

At Ortery Technologies, We help companies take better pictures and communicate more effectively with images. Whether it’s for eCommerce, product development, quality control or daily business communication, many of our computer-controlled photography studios can take pictures on pure white making still, 360 and 3D photography simple and fast.

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