Fisheye Lens

Photography is regarded as one of the most important inventions of World history. The camera, the device created to capture photos is a complex device that uses principles of light and lenses to replicate the picturization in front of it. Moreover, the ability to capture and freeze memories for a lifetime is one of the most precious gifts to humanity. With advancements in the field of photography, lenses became an integral component of the camera. Thus, a fisheye lens is one of the most innovative approaches to photography that has become an essential commodity for photography enthusiasts worldwide.

Introduction to Fisheye Lens

The main concept behind this Lens view is to project an image replicating how a fish visualizes the world in front of it. The unique spherically warped imagery is a masterful rendition of angulation and light combined.

Definition: A Fisheye lens is an ultra-wide-angle lens that is used to shoot images at an automated 180-degree angulation. 

Further, the super-wide lens helps in creating abstract images that are especially noteworthy when applied to extreme sports shots, dance move shots, or even artistic designs. Unlike regular lenses, Fisheye lens projections are much more interesting and unique and have a very dynamic appeal.

Types of Fisheye Lens

There are primarily two types of these lenses that are in use commonly. The working principle is the same. However, the images produced by each type of lens has different image effect projectiles.

• Circular Fisheye Lens – Circular Fisheye lens can easily capture 180 field view images from all the directions in one shot. This results in an image projection that has a rounded border. We refer to it commonly as a circular image, this projection usually has blackened and slightly distorted corners. Moreover, this lens is not used by professional photographers. But, it is a crowd favourite among artistic individuals who prefers experimenting with lights and angles. A circular Fisheye lens is best used in capturing skateboard shots.
• Full-frame Fisheye Lens – Full-frame Fisheye lens can easily capture a complete 180-degree view of scenery up to its diagonal range. The complete field view captured by this lens is not effective as wide-angle imagery but they generally do not have a black edging of the corners of the images. Additionally, it produces rectangular image shots, which makes it a favourite among photographers.

Properties of Fisheye Lens

1. Fisheye lens, at its widest point always projects a 180-degree angle view.
2. Curvilinear image is the term we use to refer to the trademark outward bulging that we see in an image captured using this lens.
3. The distortion seen along the outer edges of an image clicked using this lens is called Barrel distortion. It is this phenomenon that causes curvilinear imaging.
4. The focal length of a Circular Fisheye lens is between 8mm to 10mm while in the case of a Full-frame Fisheye lens it is between 15mm to 17 mm
5. The extremely high angulation of the lens projectile results in a larger field depth in the image.

Projection Created with Fisheye Lens

In an image projection created using this lens, the distance between the point and the centre of the image is always proportional to the angle of separation between both. These projects are always in clusters and captured using panorama tools.

Let us consider the image projection below:

The projection created is at 90 degrees from both sides of the pinhole. The image of the object is not very harmonic because of the uneven proportions. The image created is actually based on the position of the object which is linearly proportional to the angle of the lens projection.

If the mathematical formulation of the image projection is created then the result will be based on two sets of formulas

For, Equidistant Fisheye Projection, the formula is R = f. θ

For, Equal Area Fisheye Projection, the formula is R = 2f. sin θ2

( R denotes the radial position of the point on the screen, f is the focal length of the lens and θ is the angular difference between the optical axis and real-world)

Application of Fisheye Lens

1. Artistic photography
2. Planetarium projection of night sky
3. In Hemispherical photography
4. Visual Flight and combat Stimulation in defence and air-force
5. To create digitalized environmental maps by metallurgists.
6. To study pollution data and cloud cover by Climatologist

FAQ on Fisheye Lens

Question 1: Is a Fisheye Lens concave or convex?

Answer 1: This lens produces distinct convex images, so it is a convex lens

Question 2: What is the difference between Fisheye and wide-angle lenses?

Answer 2: The image captured with this Lens has a trademark style. It looks as though one is looking through a peephole. This is the result of outward bowing because of barrel distortion which is only seen in images that we click using this lens.