Fisheye Lens vs. Wide-Angle Lens

What is a fisheye lens?

A fisheye lens is a special type of ultra-wide angle lens. It is small and ultra-wide, and shows a distorted, spherical view of the world, most evident in the curved outer corners of the photo, known as the "fisheye effect".

Fisheye lenses happen to work very well underwater for a couple different reasons:

• They focus very closely

• There are few straight lines underwater

• Using a very wide lens allows to get very close to your subjects, giving your photograph more sharpness, and better colors when lit with a strobe.

• Behind a dome port, fisheye lenses perform better optically than regular wide-angle lenses.

The Sigma 8mm, 10mm, Sigma 15mm, Tokina 10-17mm, Nikon 8-15mm, 10.5mm, Nikon 16mm, Olympus 8mm, Inon UFL-165 and the Canon 8-15mm and 15mm are all fisheye lenses with an extra wide view up to a 180 diagonal degrees. Straight lines in the outer areas of the images will appear curved. There are even iPhone fisheye lenses.

Properties of fisheye lens:

• They usually focus very close
• They are small and light
• When shooting ultra-wide angle, you benefit from a large depth of field
• You can get very close to large subjects, maximizing color and sharpness
• They perform well behind dome ports with good corner sharpness, and they don't need a diopter
• You usually need at least 2 strobes with good angle of coverage to properly light the entire area.

Tokina 10-17mm fisheye and Sigma 10-20mm wide angle lens 

Fisheye lenses and focal length

Although people often think of a fisheye lens as wider than a rectilinear lens, it's important to note that at the same focal length, a subject at the center of a fisheye lens will be magnified the same amount as a rectilinear lens. This can be clearly seen in the example photos at the beginning of this article.

Barrel Distortion

When reading about fisheye and regular wide angle lenses, you will hear a term called barrel distortion. This distortion causes curved lines at the edges of the photo. This is a negative aspect of cheaper rectilinear wide angle lenses at their widest settings. However, on fisheye lenses, this is their main feature. That is why they are called "fisheye", and the barrel distortion should not be viewed negatively.

Correcting distortion post process

Land photographers will sometimes use software to correct the distortion of a fisheye lens. However, underwater this is rarely done, as the slight curvature of a fisheye lens is often considered a desired effect.

The easiest way to correct the distortion post process is with Lightroom.  In the Lens Corrections section, choose "Enable Profile Corrections".  Lightroom should automatically read the specs of your lens but if not, choose it from the dropdown menu.  You'll have a choice to keep the automated distortion correction or manually adjust it by using the slider bars.  

A fisheye lens is good for:

• Reef shots

• Getting really close

• Divers, models

• Large wrecks

• Mantas, whale sharks

• Schooling fish shots

• Over-under shots

• Sharks that come really close

• Close-focus wide angle of large macro subjects such as large frogfish, rhinopias, large seahorses

What is a rectilinear lens?

A rectilinear lens is any lens besides a fisheye.  Wide angle examples are Nikon 12-24mm, Canon 10-22mm, Tokina 12-24mm, Sigma 10-22mm and Olympus 9-18mm. Lines in photos taken by rectilinear lenses remain straight.

Inon and Ikelite make several "wet" wide angle lenses for compact cameras, like the Inon UWL-100 and the UWL-105AD. Their width is usually expressed as an angle of view underwater. Read more here about wet lenses.

It is important to note the 17mm on a fisheye lens is not equivalent to 17mm on a rectilinear lens. For example, the Tokina 10-17mm at 17mm is about as wide as the Nikon 12-24mm lens at 12mm. In general, a fisheye will be much wider than a rectilinear lens. You can compare angle of views on my best lenses for underwater page. However, a subject in the center of a photo will appear similar size in a fisheye and rectilinear lens (e.g. - small subject taken in the center of a 10mm fisheye vs a 10mm rectilinear). The difference will be seen away from the center, and in the edges/corner of the photo.

A rectilinear lens is good for

• Shots with straight lines where you don't want to see any curves

• Skittish pelagics, sharks, dolphins, that won't come close

• Reef shots that are easier to light the entire space

• Turtles, sea lions

• Many people use a rectilinear lens underwater, like a 10-22mm lens, because they also need a wide-angle lens for topside (out of the water) use, such as landscape photography, and they can't afford 2 wide-angle lenses. A fisheye lens has more limited use topside.

My recommended lens choices for underwater photograpy:

The Canon 8-15mm fisheye and Nikon 8-15mm fisheye lenses are the best quality full-frame fisheye lenses out there, but you pay a premium for them. On a full-frame camera, they will give a circular fisheye view at 8mm.

Canon 8-15mm circular fisheye lens

If you own a Canon dSLR, the Canon 8-15mm fisheye lens is excellent, and very sharp. With a 5D Mark II or 5D Mark III, you can get some incredible circular photos. Read our Canon 8-15mm fisheye review. 

Tokina 10-17mm fisheye lens

The Tokina 10-17mm is good on a full-frame DSLR, and really shines on a cropped-sensor DSLR because the zoom range is fully useable. Read my Tokina 10-17mm fisheye lens review.

Sigma 15mm fisheye lens

If you are shooting a full frame dSLR, you may be interested in the excellent Sigma 15mm F2.8 fisheye lens. The lens is very sharp, focuses close and fast, and gives a 180 degree angle of view underwater with a full-frame dSLR. It is recommended over the Nikon 16mm fisheye, and the Canon 15mm fisheye, because of its closer focus distance, which is very important for underwater optics. Canon shooters will also want to check out the Canon 8-15mm fisheye, mentioned in the circular fisheye section below.

Read our Sigma and Tokina fisheye lens full-frame comparison

Micro-four thirds cameras

The Panasonic 8mm fisheye lens is an great choice for micro-four thirds cameras such as the Olympus E-M1 Mark II, E-PL1 - E-PL7, or the Panasonic GH4, GH5 or G9. The newer Olympus 8mm Pro Fisheye has a larger aperture, but is slightly heavier.

Fisheye lens for Sony NEX cameras

The Sony NEX fisheye conversion lens is excellent, and costs less than $150. It screws onto the Sony NEX 16mm pancake lens.

Circular fisheye lenses

The Sigma 8mm fisheye lens is a circular fisheye lens. Results are best on a full-frame dSLR camera.

Sigma also makes the Sigma 4.5mm f/2.8 circular fisheye lens for cropped sensor cameras. It has a 180 degree of view in all directions on a cropped-sensor camera. 

Check out 10 Amazing Photos you can Shoot with a Fisheye Lens.

Continue reading about Camera Lens Basics

Recommended Tutorials:

• Best lenses for underwater use

• Strobe positions for underwater

• Wide-angle underwater photography

• Underwater composition

• Dome port optics

• Tokina 10-17mm fisheye review

• Tokina 10-17mm fisheye on a NIkon D80