How wide is "Wide Angle?"

[Peter Guy]

"Wide Angle" comes up often in discussions of "What camera [or lens] should I buy?"

Some of the comments have led me to wonder, "How wide IS wide angle?" And, in addition to that, what are the tradeoffs between "wide angle" and "super wide angle" when shooting?

Is a 70degree Field of View WA -- 100degrees -- 150?

 

[Kilili]

Nikon mostly uses only the term "wide". For 35mm cameras, it's 35mm on down.
The 10.5mm and 14mm, and 20mm are described as "ultra-wide", with 10.5 also described as "fisheye",and the 16mm another fisheye, as "super-wide". Go figure.
Fisheye lenses present a convex appearance. The actual image is round, but generally mapped to a rectilinear presentation, and hence distorted.

Wide angle lenses tend to introduce barrel distortion, the wider, the more so.

 

[Zung]

From my limited experience, and assuming you have a dome port and using 35mm equivalent:

• 35mm is your entry level
• 28mm is OK
• 24mm is good
• 20-22mm is great
• Below 20mm gets you the weid fisheye effect

My bias: I used to shoot fishes mostly. The WA lets you get as little water between you and your subject as the subject allows. Most animals have a "safety perimeter", but that's negociable to a point; it just takes time (and air).

 

[Kilili]

Wikipedia provides more accurate def, as follows:

Types of fisheye lenses

Circular:
In a circular fisheye lens, the image circle is inscribed in the film or sensor area; in a full-frame fisheye lens the image circle is circumscribed around the film or sensor area.
Further, different fisheye lenses distort images differently, and the manner of distortion is referred to as their mapping function. A common type for consumer use is equisolid angle.

The first types of fisheye lenses to be developed were "circular fisheyes" — lenses which took in a 180° hemisphere and projected this as a circle within the film frame. Some circular fisheyes were available in orthographic projection models for scientific applications. These have a 180° vertical angle of view, and the horizontal and diagonal angle of view are also 180°. Most circular fisheye lenses cover a smaller image circle than rectilinear lenses, so the corners of the frame will be completely dark.

Full-frame
As fisheye lenses gained popularity in general photography, camera companies began manufacturing fisheye lenses that enlarged the image circle to cover the entire 35 mm film frame, and this is the type of fisheye most commonly used by photographers.
The picture angle produced by these lenses only measures 180 degrees when measured from corner to corner: these have a 180° diagonal angle of view, while the horizontal and vertical angles of view will be smaller; for an equisolid angle-type 15 mm full-frame fisheye, the horizontal FOV will be 147°, and the vertical FOV will be 94°.[2]
The first full-frame fisheye lens to be mass-produced was a 16 mm lens made by Nikon in the early 1970s. Digital cameras with APS-C sized sensors require a 10.5 mm lens to get the same effect as a 16 mm lens on a camera with full-frame sensor.[3]

 

[Thalassamania]

Nikon mostly uses only the term "wide". For 35mm cameras, it's 35mm on down.
The 10.5mm and 14mm, and 20mm are described as "ultra-wide", with 10.5 also described as "fisheye",and the 16mm another fisheye, as "super-wide". Go figure.
Fisheye lenses present a convex appearance. The actual image is round, but generally mapped to a rectilinear presentation, and hence distorted.

Wide angle lenses tend to introduce barrel distortion, the wider, the more so.

From my limited experience, and assuming you have a dome port and using 35mm equivalent:

• 35mm is your entry level
• 28mm is OK
• 24mm is good
• 20-22mm is great
• Below 20mm gets you the weid fisheye effect

My bias: I used to shoot fishes mostly. The WA lets you get as little water between you and your subject as the subject allows. Most animals have a "safety perimeter", but that's negociable to a point; it just takes time (and air).

If you are using a dome port then a "normal" lens has a focal length of about 55mm. Anything shorter than that is "wide." Where ultra-wide and such starts and ends it up to the marketeers. Fisheye, is a special case. Fisheye lenses typically capture almost a full hemisphere.

Wiki describes it well:

In photography, a fisheye lens is a wide-angle lens that takes in an extremely wide, hemispherical image. Originally developed for use in meteorology[1] to study cloud formation and called "whole-sky lenses", fisheye lenses quickly became popular in general photography for their unique, distorted appearance. They are often used by photographers shooting broad landscapes to suggest the curve of the Earth. Hemispherical photography is used for various scientific purposes to study plant canopy geometry and to calculate near-ground solar radiation.

The focal lengths of fisheye lenses depend on the film format. For the popular 35 mm film format, typical focal lengths of fisheye lenses are between 8 mm and 10 mm for circular images, and 15–16 mm for full-frame images. For digital cameras using smaller electronic imagers such as 1/4" and 1/3" format CCD or CMOS sensors, the focal length of "miniature" fisheye lenses can be as short as 1 to 2mm.

All the ultra-wide angle lenses suffer from some amount of barrel distortion. While this can easily be corrected for moderately wide angles of view, rectilinear ultra-wide angle lenses with angles of view greater than 90 degrees are difficult to design. Fisheye lenses achieve extremely wide angles of view by forgoing a rectilinear image, opting instead for a special mapping (for example: equisolid angle), which gives images a characteristic convex appearance.
​

 

[Kukuisa]

Anything wider than normal is wide.
When a normal underwater lens has a focal lenght of 35 mm, you could say that anything less than 35mm is considered a wide angle lens. That lens has an angle of view of about 50°, making any field greater than 50° wide.

 

[newmanl]

The "what is wide" has been answered, I think. I've always thought that anything with a focal length shorter than 50mm was considered wide, and gets wider the shorter one goes.

As for the practical trade-offs when shooting (underwater), generally wider fields of view can be more challenging to properly light. Two strobes, in order to cover the FoV, are usually the recommended rig. Also, the wider the FoV the more likely you'll light up whatever is in the water column... and in the PNW during the summer, wide angle (or super/ultra wide angle) can be very frustrating because of backscatter.

Lastly, although topside the fisheye lenses create funky-looking images, underwater behind a curved domeport, they excel! Because the virtual image created by the dome is curved, and since fisheyes can focus on a "curved image", the fisheye lenses tend to be much sharper than rectalinear lenses (non-fisheye wide angle lenses) in the corners of the frame.

It's no coincidence that one of the most highly-rated lenses for wide angle shooting underwater is a 10-17 mm fisheye!

Hope that helps.

Lee

 

[scottfiji]

Peter, as you can probably tell, different people use these terms in different ways. Different people will claim different definitions - and that's ok.

I generally recommend people try to use a 100 degree diagonal angle of view or larger for "wide angle", for the best results.

hope this helps,
Scott

 

[Thalassamania]

Go to my profile page to see "fisheye."