Fish-Eye Mamiya-Sekor C 37mm F/4.5

Fisheye lens • Film era • Discontinued

FISH-EYE An ultra-wide angle lens with strong uncorrected barrel distortion and extreme 180-degree angle of view.
C The multi-layer coating is applied to the surface of lens elements. It boosts light transmission, ensures sharp and high contrast images, minimizes ghosting and flares.
Fish-Eye Mamiya-Sekor C 37mm F/4.5

Model history ⋅ モデル履歴

Mamiya-Sekor Fisheye Z 37mm F/4.56x7Mamiya RZ67A9 - 60.257m--
Fish-Eye Mamiya-Sekor C 37mm F/4.56x7Mamiya RB67A9 - 60.257m--

Mamiya RB67 Professional

Medium format MF film SLR camera

Announced ⋅ 発表:1970
Mount ⋅ マウント:Mamiya RB67
Format ⋅ フォーマット:69.5 × 56mm
Shutter type ⋅ シャッタータイプ:In-lens leaf shutter ⋅ レンズ内リーフシャッター
Exposure metering ⋅ 露出測光:No ⋅ 番号
Dimensions ⋅ 寸法:139x104x226mm (*)
Weight ⋅ 重さ:2595g (*)

* - with Mamiya Sekor 90mm F/3.8

Mamiya RB67 Professional S

Medium format MF film SLR camera

Announced ⋅ 発表:1974
Mount ⋅ マウント:Mamiya RB67
Format ⋅ フォーマット:69.5 × 56mm
Shutter type ⋅ シャッタータイプ:In-lens leaf shutter ⋅ レンズ内リーフシャッター
Exposure metering ⋅ 露出測光:No ⋅ 番号
Dimensions ⋅ 寸法:144x104x228mm (*)
Weight ⋅ 重さ:2705g (*)

* - with Mamiya Sekor 90mm F/3.8 C

Features highlight ⋅ 機能のハイライト

Extreme AoV
Macro 1.2:1
Built-in hood

Specification ⋅ 仕様

Production details ⋅ 制作内容
Announced ⋅ 発表:<No information ⋅ 情報なし>
Production status ⋅ 生産状況:Discontinued ⋅ 製造中止
Production type ⋅ 生産タイプ:Mass production ⋅ 大量生産
Original name ⋅ 元の名前:FISH EYE MAMIYA-SEKOR C 1:4.5 f=37mm
Optical design ⋅ 光学設計
Focal length ⋅ 焦点距離:37mm
Speed ⋅ スピード:F/4.5
Maximum format ⋅ 最大フォーマット:Medium format ⋅ 中判 6x7
Mount ⋅ マウント:Mamiya RB67
Flange focal distance ⋅ フランジバック:111mm
Lens construction ⋅ レンズ構造:9 elements ⋅ 要素 - 6 groups ⋅ グループ
Convex protruding front element ⋅ 凸状に突き出たフロントエレメント
Diaphragm mechanism ⋅ ダイヤフラムメカニズム
Diaphragm type ⋅ ダイヤフラムタイプ:Automatic ⋅ 自動
Number of blades ⋅ 絞り羽根の数:<No information ⋅ 情報なし>
Built-in leaf shutter ⋅ 内蔵リーフシャッター
Type ⋅ タイプ:Mechanical ⋅ 機械的 Seiko #1
Speeds ⋅ 速度:1 - 1/400 + T
Focusing ⋅ フォーカシング
Closest focusing distance ⋅ 最短撮影距離:0.257m
Closest working distance ⋅ 最短作動距離:0.0064m
Maximum magnification ratio ⋅ 最大倍率:1.2:1 at the closest focusing distance ⋅ 最寄りの距離で
Focusing method ⋅ フォーカシング方法:<No information ⋅ 情報なし>
Focusing modes ⋅ フォーカシングモード:Manual focus only ⋅ マニュアルフォーカスのみ
Manual focus control ⋅ マニュアルフォーカス制御:None; focusing from the camera ⋅ なし; カメラからの焦点合わせ
Physical characteristics ⋅ 体格的特徴
Weight ⋅ 重量:1240g
Maximum diameter x Length ⋅ 最大直径x長さ:⌀112×93mm
Accessories ⋅ 付属品
Filters ⋅ フィルタ:Removable front filters are not accepted ⋅ 取り外し可能なフロントフィルターは使用できません
Screw-type ⋅ ネジ式 40.5mm (rear ⋅ 後方)
Lens hood ⋅ レンズフード:Built-in ⋅ ビルトイン petal-shaped ⋅ 花びらの形

Manufacturer description #1

The 37mm f/4.5 lens is of the so-called 'diagonal plane' fisheye type. It is a lens that permits special effects and unusual graphic treatment of the subject. As the widest of the wide-angle lenses, it can also be used for general photography.

Manufacturer description #2

The Mamiya-Sekor 37mm f/4.5 Fisheye lens has a diagonal angle of view of 180 degrees and is ideal for interiors, panoramic scenes, and creative imagery. Because it is a fisheye lens of the "equidistance projection system" type with no shrinkage of the image at the edges.

The Mamiya-Sekor 37mm f/4.5 Fisheye lens is designed to accept 40.5 screw-in filters in the rear of the lens. A UV filter is preattached to the lens, and three other filters (Y48, R60, LB-A) are in the filter case.

If two, or more, filters were to be used simultaneously, the mirror would strike the outermost filter, damaging the camera. To prevent this from occurring, the filters accompanying the lens are not front-threaded.

As the lens is designed to be used with a filter always in place, be sure to attach any one filter to the lens.

Typical application ⋅ 典型的なアプリケーション

scientific and industrial photography ⋅ 科学および産業写真

Comments ⋅ コメント


Based on my measuring the horizontal angle of view is (around) 107 degrees for 33cm measuring distance (from the front lens element).

Your comment ⋅ あなたのコメント

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35mm full frame

43.27 24 36
  • Dimensions: 36 × 24mm
  • Aspect ratio: 3:2
  • Diagonal: 43.27mm

Fisheye lens

A fisheye lens is a type of ultra-wide angle lenses with extreme 180 degree angle of view. Unlike conventional wide-angle lenses, fisheyes are not corrected for distortion - strong barrel distortion is a characteristic of all lenses of such class.

Fisheye lenses are normally used for specialized purposes and unusual special effects in advertising, commercial, scientific, surveillance, meteorologic and astronomic photography, but also popular for shooting extremely wide landscapes, interiors, action sports and even funny close-up portraits.

There are two types of fisheye lenses:

Travellers' choice


Among autofocus lenses designed for 35mm full-frame mirrorless cameras only. Speed of standard and telephoto lenses is taken into account.

Professional lens (Top class)

One of the best fisheye primes

According to; among lenses designed for the same maximum format and mount.

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Cannot compare the lens to itself.

Quality control issues

The manufacturer of this lens does not provide adequate quality control. If you do decide to purchase this lens, do not order it online, but choose the best copy available in the store. In any case, there may also be problems with the build quality, and warranty repairs can take months.

Image stabilizer

A technology used for reducing or even eliminating the effects of camera shake. Gyro sensors inside the lens detect camera shake and pass the data to a microcomputer. Then an image stabilization group of elements controlled by the microcomputer moves inside the lens and compensates camera shake in order to keep the image static on the imaging sensor or film.

The technology allows to increase the shutter speed by several stops and shoot handheld in such lighting conditions and at such focal lengths where without image stabilizer you have to use tripod, decrease the shutter speed and/or increase the ISO setting which can lead to blurry and noisy images.


Sorry, no additional information is available.

Original name

Lens name as indicated on the lens barrel (usually on the front ring). With lenses from film era, may vary slightly from batch to batch.


Format refers to the shape and size of film or image sensor.

35mm is the common name of the 36x24mm film format or image sensor format. It has an aspect ratio of 3:2, and a diagonal measurement of approximately 43mm. The name originates with the total width of the 135 film which was the primary medium of the format prior to the invention of the full frame digital SLR. Historically the 35mm format was sometimes called small format to distinguish it from the medium and large formats.

APS-C is an image sensor format approximately equivalent in size to the film negatives of 25.1x16.7mm with an aspect ratio of 3:2.

Medium format is a film format or image sensor format larger than 36x24mm (35mm) but smaller than 4x5in (large format).

Angle of view

Angle of view describes the angular extent of a given scene that is imaged by a camera. It is used interchangeably with the more general term field of view.

As the focal length changes, the angle of view also changes. The shorter the focal length (eg 18mm), the wider the angle of view. Conversely, the longer the focal length (eg 55mm), the smaller the angle of view.

A camera's angle of view depends not only on the lens, but also on the sensor. Imaging sensors are sometimes smaller than 35mm film frame, and this causes the lens to have a narrower angle of view than with 35mm film, by a certain factor for each sensor (called the crop factor).

This website does not use the angles of view provided by lens manufacturers, but calculates them automatically by the following formula: 114.6 * arctan (21.622 / CF * FL),


CF – crop-factor of a sensor,
FL – focal length of a lens.


A lens mount is an interface — mechanical and often also electrical — between a camera body and a lens.

A lens mount may be a screw-threaded type, a bayonet-type, or a breech-lock type. Modern camera lens mounts are of the bayonet type, because the bayonet mechanism precisely aligns mechanical and electrical features between lens and body, unlike screw-threaded mounts.

Lens mounts of competing manufacturers (Canon, Nikon, Pentax, Sony etc.) are always incompatible. In addition to the mechanical and electrical interface variations, the flange focal distance from the lens mount to the film or sensor can also be different.

Lens construction

Lens construction – a specific arrangement of elements and groups that make up the optical design, including type and size of elements, type of used materials etc.

Element - an individual piece of glass which makes up one component of a photographic lens. Photographic lenses are nearly always built up of multiple such elements.

Group – a cemented together pieces of glass which form a single unit or an individual piece of glass. The advantage is that there is no glass-air surfaces between cemented together pieces of glass, which reduces reflections.

Flange focal distance

The flange focal distance (FFD), sometimes called the "flange back", is the distance from the mechanical rear end surface of the lens mount to the focal plane.

Focal length

The focal length is the factor that determines the size of the image reproduced on the focal plane, picture angle which covers the area of the subject to be photographed, depth of field, etc.


The largest opening or stop at which a lens can be used is referred to as the speed of the lens. The larger the maximum aperture is, the faster the lens is considered to be. Lenses that offer a large maximum aperture are commonly referred to as fast lenses, and lenses with smaller maximum aperture are regarded as slow.

In low-light situations, having a wider maximum aperture means that you can shoot at a faster shutter speed or work at a lower ISO, or both.

Closest focusing distance

The minimum distance from the focal plane (film or sensor) to the subject where the lens is still able to focus.

Closest working distance

The distance from the front edge of the lens to the subject at the maximum magnification.

Magnification ratio

Determines how large the subject will appear in the final image. For example, a magnification ratio of 1:1 means that the image of the subject formed on the film or sensor will be the same size as the subject in real life. For this reason, a 1:1 ratio is often called "life-size".

Electromagnetic diaphragm control system

Provides highly accurate diaphragm control and stable auto exposure performance during continuous shooting.

Convex protruding front element

The convex front element protrudes from the lens barrel, making it impossible to use filters.

Manual diaphragm

The diaphragm must be stopped down manually by rotating the detent aperture ring.

Preset diaphragm

The lens has two rings, one is for pre-setting, while the other is for normal diaphragm adjustment. The first ring must be set at the desired aperture, the second ring then should be fully opened for focusing, and turned back for stop down to the pre-set value.

Semi-automatic diaphragm

The lens features spring mechanism in the diaphragm, triggered by the shutter release, which stops down the diaphragm to the pre-set value. The spring needs to be reset manually after each exposure to re-open diaphragm to its maximum value.

Automatic diaphragm

The camera automatically closes the diaphragm down during the shutter operation. On completion of the exposure, the diaphragm re-opens to its maximum value.

Number of blades

As a general rule, the more blades that are used to create the aperture opening in the lens, the rounder the out-of-focus highlights will be.

Some lenses are designed with curved diaphragm blades, so the roundness of the aperture comes not from the number of blades, but from their shape. However, the fewer blades the diaphragm has, the more difficult it is to form a circle, regardless of rounded edges.

At maximum aperture, the opening will be circular regardless of the number of blades.


Excluding case or pouch, caps and other detachable accessories (lens hood, close-up adapter, tripod adapter etc.).

Maximum diameter x Length

Excluding case or pouch, caps and other detachable accessories (lens hood, close-up adapter, tripod adapter etc.).

For lenses with collapsible design, the length is indicated for the working (retracted) state.

Weather sealing

A rubber material which is inserted in between each externally exposed part (manual focus and zoom rings, buttons, switch panels etc.) to ensure it is properly sealed against dust and moisture.

Lenses that accept front mounted filters typically do not have gaskets behind the filter mount. It is recommended to use a filter for complete weather resistance when desired.

Fluorine coating

Helps keep lenses clean by reducing the possibility of dust and dirt adhering to the lens and by facilitating cleaning should the need arise. Applied to the outer surface of the front and/or rear lens elements over multi-coatings.


Lens filters are accessories that can protect lenses from dirt and damage, enhance colors, minimize glare and reflections, and add creative effects to images.

Lens hood

A lens hood or lens shade is a device used on the end of a lens to block the sun or other light source in order to prevent glare and lens flare. Flare occurs when stray light strikes the front element of a lens and then bounces around within the lens. This stray light often comes from very bright light sources, such as the sun, bright studio lights, or a bright white background.

The geometry of the lens hood can vary from a plain cylindrical or conical section to a more complex shape, sometimes called a petal, tulip, or flower hood. This allows the lens hood to block stray light with the higher portions of the lens hood, while allowing more light into the corners of the image through the lowered portions of the hood.

Lens hoods are more prominent in long focus lenses because they have a smaller viewing angle than that of wide-angle lenses. For wide angle lenses, the length of the hood cannot be as long as those for telephoto lenses, as a longer hood would enter the wider field of view of the lens.

Lens hoods are often designed to fit onto the matching lens facing either forward, for normal use, or backwards, so that the hood may be stored with the lens without occupying much additional space. In addition, lens hoods can offer some degree of physical protection for the lens due to the hood extending farther than the lens itself.