Understanding Ultra-Wide Angle Lenses

Here is what you need to know about ultra-wide angle lenses

An ultra-wide angle lens produces images with extremely wide angle of view. It is a popular choice among architecture and landscape photographers, because it can fit much of the foreground, as well as the surrounding elements in the photo.

Some of the ultra-wide angle lenses are of fisheye type, while others are rectilinear. In this article, we will go through both types and explain their differences.

What is an Ultra-Wide Angle Lens?

An ultra-wide angle lens is a lens that covers focal lengths shorter than 24mm in full-frame equivalent field of view. This includes both prime lenses, as well as zoom lenses.

For zoom lenses, if the wide-end of the focal range is below 24mm, it is considered to be an ultra-wide angle lens, even if its long end includes or exceeds 24mm. For example, both Nikon 14-24mm f/2.8G, as well as Nikon 16-35mm f/4G VR are ultra-wide angle lenses when mounted on a full-frame camera.

It is important to note that for a lens to be designated as an ultra-wide angle, both focal length and sensor size have to be taken into account.

This means that while a 20mm f/1.8 prime lens would be considered ultra-wide angle lens on a full-frame camera, it would no longer be considered as such on an APS-C sensor. This is due to 1.5x sensor cropping (also known as crop factor) that changes the field of view to roughly 30mm in full-frame equivalent. A similar 20mm lens mounted on a 1” sensor would fall into the “standard” range, with its equivalent FF field of view of 54mm.

Sensor Size vs Focal Length

Below is a table of different sensor sizes and focal lengths for ultra-wide angle lens designation:

  • iPhone with 1/2.9” sensor (7.1x Crop Factor): Shorter than 3.4mm
  • Smartphone with 1/2.3” sensor (5.62x Crop Factor): Shorter than 4.3mm
  • 1” Sensor (2.7x Crop Factor): Shorter than 9mm
  • Micro Four Thirds (2.0x Crop Factor): Shorter than 12mm
  • APS-C (1.5x Crop Factor): Shorter than 16mm
  • Full-Frame (1.0x Crop Factor): Shorter than 24mm
  • Medium Format (0.78x Crop Factor): Shorter than 31mm

Who are Ultra-Wide Angle Lenses For?

Ultra-wide angle lenses are used by many different types of photographers, but they are arguably most popular among architecture and landscape photographers.

Architecture photographers use ultra-wide angle lenses to fit tall buildings into their frame. Real-estate photographers, in particular, often use ultra-wide angle lenses to photograph the interior.

Landscape photographers on the other hand, use ultra-wide angle lenses to exaggerate the relative size of foreground objects, while including vast landscapes in the background.

Other types of photographers also occasionally rely on ultra-wide angle lenses. For example, portrait photographers utilize ultra-wide angle lenses for photographing people in tight spaces, shooting environmental portraits and photographing very large groups of people.

How Ultra-Wide Angle Lenses Affect Depth of Field

In photography, depth of field is affected by a number of different variables such as aperture, focal length, camera to subject distance and sensor size. And without a doubt, focal length is one of the biggest factors that influences the size of depth of field.

An ultra-wide angle lens has an extremely short focal length, which results in large depth of field, even when using relatively large apertures. Since ultra-wide angle lenses can reach infinity focus at close distances, they are often preferable when wanting to make both foreground and background appear sharp in images.

In addition, one does not have to deal with diffraction issues related to using very small apertures. Once hyperfocal distance is established and focused on, even larger apertures like f/4 can make the whole scene appear sharp from front to back at moderate camera-to-subject distances when using ultra-wide angle lenses.

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