Leitz Wetzlar Visoflex II

Reflex housing • Discontinued

Manufacturer description #1

From the LEICA photography magazine (1958, No. 4):

A completely redesigned reflex-focusing housing - the Visoflex II - is another interesting newcomer to the Leica System. Since it is considerably shallower, front to back, than the former Visoflex, the II will permit properly mounted 90mm lenses to focus from infinity down to 3 1/2 feet.

A single rigid arm on the Visoflex II releases both its mirror and the camera shutter; adjustment of the time-lag between mirror release and shutter release is made very simply via a knurled ring.

Two magnifiers will be available - one (4X) for eye-level use, a second (5X) for convenience when the camera is held below eye level.

The Visoflex II will be produced in both screw- and bayonet-mount models to fit all Leica models with interchangeable lenses. Adapter rings will be available so that lenses from 90mm to 400mm focal length can be used with the new Visoflex II. Prices and availability will be announced later.

Manufacturer description #2

From the LEICA photography magazine (1959, No. 1):

Perhaps the most striking thing about the new Visoflex is its compactness. Since it is 22.5mm shallower than the Visoflex I, it will focus even 90mm lenses (in short mount) to infinity. Both the new 90mm Summicron f/2 in short mount and lens units of the 90mm Elmar f/4 in special focusing mount can be used on the Visoflex II. (The collapsible, bayonet-mounting 90mm Elmar cannot be used, since its lens unit is not removable.) The extension tube OTQNO used on the Visoflex II makes possible close-range focusing between 40 and 26 inches with the rigid 90mm Elmar lenses.

rigid release bar

Another feature of the Visoflex II is its single, rigid shutter-and-mirror release bar. One press of this bar trips both the reflex mirror and the Leica shutter in proper sequence. A simple knurled ring adjusts the bar to fit individual camera shutter releases and insures a rapid, correctly-timed sequence of shutter and mirror release. Pressing a second lever (positioned to fall naturally under the middle finger of your right hand) returns the mirror to viewing position instantly. For those who use a cable release when working from a tripod or copying stand, there is a special socket which accepts the cable release which fits the "M" model Leicas. The cable release trips both mirror and shutter - the same result as using the rigid release bar, but with less chance of vibration on long exposures.

lens adapter

The short-mounted 90mm Summicron lens is designed to fit the Visoflex II, and the lens units of other rigid-mount 90mm Elmar lenses also fit the new housing when used in a special focusing mount. But the mounts of the 125mm, 135mm Hektor (short mount), 200mm and 400mm Leica lenses require an adapter which bayonets to the front of the Visoflex II. This is because these lenses are designed for the Visoflex I, which is deeper, front to back, than the new housing. The adapter adds the necessary length to make the lenses focus properly on the film plane.

The adapter permits the Visoflex II, with camera attached, to be rotated through 90° for taking vertical pictures while working from a tripod. When the adapter is not used (as with the short-mounted 90mm lenses) a ball-joint tripod head is necessary to take verticals from a tripod. The Visoflex II and the special adapter for long-focus lenses have both European- and American-thread tripod sockets.

two magnifiers

The compactness and the single release-bar of the Visoflex II suit it admirably for hand-held camera work, especially when it is used with the direct-vision magnifier. This 4X magnifier contains a prism and yields an upright, unreversed image which is ideal for eye-level shooting of general scenes and action pictures. A 5X simple magnifier is used for pictures taken from a vertical copying stand or for extra-low angle shots. It produces an upright, but laterally reversed image. Both magnifiers are adjustable to compensate for individual eyesight variations from +1.5 to -2 diopters. The superfine grain of the ground glass screen and the high light transmission of the magnifiers combine to produce an exceptionally brilliant image with incomparable corner-to-corner sharpness for fast, easy focusing and framing of the subject.

The Visoflex II will be available in both screw- and bayonet-mounting models. However, the screw- mounting model cannot be adapted for use with "M" model Leicas via a bayonet adapter, because the shutter release button is differently positioned on the M 2 and M 3 than it is on screw-mounting Leicas. The screw-mounting Visoflex II is designed to fit older, threaded models of the Leica, as well as the Ig and Illg. But, since the former are somewhat lower in height than the "g" cameras, the shutter release bar of the new housing includes a small, removable stud which provides extra "reach" for the release bar when it is used on "f" series or earlier Leicas.

Manufacturer description #3

The Visoflex II is a recent and more compact version of the Visoflex I. It is 22.5mm shallower, front to back, than the Visoflex I, and so will permit lenses of less than 135mm focal length to be focused to infinity - specifically the 90mm lenses and the 65mm Elmar.

A rigid, bar-type mirror-and-shutler release plus a 4X prism-type magnifier make hand-held, eye-level photography easy with the Visoflex II. The new 65mm Elmar f/3.5 and the short-mounted 90mm Summicron f/2 lens are especially useful with the new housing, and lens units of the 90mm Elmarit and rigid 90mm Elmar f/4 lenses can also be used with adapters (the collapsible 90mm lens cannot be focused to infinity with the Visoflex II). All other short-mounted Leica lenses designed for use on the Visoflex I can also be used with the Visoflex II via a simple adapter which bayonets to the front of the new housing and accepts the threaded mount of the older lenses. The Visoflex adapts for copy-stand or low-angle work by replacement of the prism-type viewfinder with a simple 5X magnifier. (The magnifiers of the Visoflex I and Visoflex II are interchangeable only on the housing for which they are designed, however. That is, those for the Visoflex I do not fit the Visoflex II and vice versa.) The mirror and shutter should be triggered with a cable release rather than the bar release when working from a tripod or copying stand. This can be done via a socket which will accept any cable release which fits the Leica M 3.

Like the Visoflex I, the new unit is available in models to fit either bayonet- or screw-mounting Leicas. The screw-mounting Visoflex II cannot be adapted to bayonet-mounting Leicas via a bayonet adapter, since the length of the shutter release bar is different on the two Visoflex II models. Also, because of a difference in height between the lllg and earlier screw-mounting Leicas, a removable extension "finger" is supplied with the screw-mounting Visoflex II. This increases the reach of the shutter release bar and is used with IIIf or earlier models of the Leica.

Manufacturer description #4

The VISOFLEX II is an accessory that enables you to change the rangefinder Leica into a compactly efficient single-lens reflex camera whenever you wish. This marvel of 35mm versatility and enjoyment is a pivotal member of the Leica System, the world's most complete system of photography.

Choice between rangefinder and through-the-lens photography is not just a matter of taste. Each has definite advantages; that's why both have always been provided for in the Leica System.

When short and normal lenses are being used at normal distances, rangefinder viewing and focusing is easier and very much more accurate. Through-the-lens viewing and focusing offers advantages when long lenses are being used or in extreme close-up photography.

When you own a Leica, you may choose from rangefinder-coupled lenses 21mm to 135mm in length. With the same Leica and a VISOFLEX II, you may use lenses from 65mm to 400mm in length. A number of the lenses can be used with both systems. Designed for fast hand-held shooting and eye-level comfort, the VISOFLEX II delivers an upright, unreversed image on a ground-glass screen so fine-grained and clear you forget it's there. You also forget the VISOFLEX II is there, it's so compact and so much a part of the Leica. The smooth precision operation is typical of any Leica-accessory combination.

Manufacturer description #5

The Leica is designed to cope with every photographic situation with speed and certainty - designed to give pictures that are full of life.

More than three decades of leadership in the 35 mm camera field have culminated in the Leica M 3 and M 2, along with an extensive line of lenses and accessories which constitute the Leica System. The basis of this system is the Leica "M" combined range-viewfinder, undoubtedly the fastest, most accurate and easiest to use of all focusing devices. With ultra-bright rangefinders and built-in viewfinder lens-field indication and automatic parallax compensation over the full focusing range, the Leica M 2 and M 3 permits even a beginner to focus quickly and easily even when working in dim light or with high-speed lenses.

There are, however, occasions in which reflex focusing and viewing of a completely parallax-free groundglass image is preferable as, for example, in close-up work, macrophotography, and when using telephoto lenses. Here the Leicaman has the advantage of the Visoflex II which instantly converts his rangefinder Leica to a compactly efficient single-lens reflex. More than this, the 90- and 35 mm Leica lenses may actually be employed with either rangefinder or reflex focusing. This enables the Leicamen to choose not only the best focal length, but the ideal focusing method for individual subject conditions as well.

VISOFLEX II details

  • Simple 5x magnifier (laterally reversed image) 16 461 with eyesight adjustment from +2 to -1.75 diopters
  • Image-erecting, right-way-round 4x prism magnifier 16 460 with eyesight adjustment from +1.75 to -2.5 diopters
  • Release button with (beneath it) adjusting screw for timing mirror movement and shutter release
  • Release lever acting directly on LEICA release button, causing reflex mirror to rise before shutter is released
  • Bayonet fitting (or threaded mount) for attaching VISOFLEX II to LEICA camera body
  • Conical thread for standard cable releases
  • Adjusting screw for aligning screw-thread VISOFLEX II with thread-mount LEICA camera
  • Finegrain groundglass focusing screen with etched-in black circle to aid in individual eyepiece adjustment
  • Return-lever for reflex mirror
  • Reflex mirror
  • Catch for locking or releasing the interchangeable lenses
  • Tripod sockets, 3/8 inch and 1/4 inch

Special advantages of the VISOFLEX II, reflex housing for the LEICA

The VISOFLEX II attaches to the LEICA in exactly the same way as an interchangeable lens, thus giving you the opportunity of using reflex viewing and focusing without sacrificing the inherent technical advantages of the combined range-viewfinder of your LEICA M 2 or M 3.

Because the VISOFLEX II is an independent unit it has been possible to provide a very large mirror groundglass and magnifier which ensures maximum viewing brightness and focusing accuracy with even illumination out to the picture edges. The VISOFLEX II has a true groundglass which increases focusing speed and accuracy by virtue of its great brightness. The groundglass image has the full size of the LEICA frame.

The large viewing magnifiers with focusing eyepieces are readily interchangeable for horizontal or vertical camera positioning and enlarge the groundglass image 4x or 5x respectively.

For infinity focus the VISOFLEX II accepts LEICA lenses with focal lengths from 65- to 400 mm. Shorter-focus LEICA lenses are adaptable for extreme close-up and macro applications. The LEITZ FOCUSING BELLOWS II, a new accessory for the VISOFLEX II greatly simplifies and facilitates the problems of close-up photography.

Note: An improved Visoflex, the IIa, is now available, in addition to the Visoflex II. It is virtually identical to the Visoflex II but features an automatic, rapid-return mirror. A Visoflex II can be converted to a IIa.

From the editor

Introduced in 1958.

A lighter and more compact reflex housing with optical thickness reduced to 40mm to allow lenses of 65mm and above to be focused to infinity.

Visoflex IIa (1962) offered the choice of automatic mirror reset or mirror locked up when pressure on the release was relaxed. The mirror reset lever was replaced with a knurled knob engraved with a black and a red dot to indicate the selected mirror setting.

Micro-Visoflex II was a special version for micro work with interchangeable plain and ground glass screens which had a D-shaped finger grip and were slid into rails on the top of the Visoflex body. This version also had a special focusing magnifier, rising to a much flatter eyepiece than the standard OTVXO.

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Chromatic aberration

There are two kinds of chromatic aberration: longitudinal and lateral. Longitudinal chromatic aberration is a variation in location of the image plane with changes in wave lengths. It produces the image point surrounded by different colors which result in a blurred image in black-and-white pictures. Lateral chromatic aberration is a variation in image size or magnification with wave length. This aberration does not appear at axial image points but toward the surrounding area, proportional to the distance from the center of the image field. Stopping down the lens has only a limited effect on these aberrations.

Spherical aberration

Spherical aberration is caused because the lens is round and the film or image sensor is flat. Light entering the edge of the lens is more severely refracted than light entering the center of the lens. This results in a blurred image, and also causes flare (non-image forming internal reflections). Stopping down the lens minimizes spherical aberration and flare, but introduces diffraction.

Astigmatism

Astigmatism in a lens causes a point in the subject to be reproduced as a line in the image. The effect becomes worse towards the corner of the image. Stopping down the lens has very little effect.

Coma

Coma in a lens causes a circular shape in the subject to be reproduced as an oval shape in the image. Stopping down the lens has almost no effect.

Curvature of field

Curvature of field is the inability of a lens to produce a flat image of a flat subject. The image is formed instead on a curved surface. If the center of the image is in focus, the edges are out of focus and vice versa. Stopping down the lens has a limited effect.

Distortion

Distortion is the inability of a lens to capture lines as straight across the entire image area. Barrel distortion causes straight lines at the edges of the frame to bow toward the center of the image, producing a barrel shape. Pincushion distortion causes straight lines at the edges of the frame to curve in toward the lens axis. Distortion, whether barrel or pincushion type, is caused by differences in magnification; stopping down the lens has no effect at all.

The term "distortion" is also sometimes used instead of the term "aberration". In this case, other types of optical aberrations may also be meant, not necessarily geometric distortion.

Diffraction

Classically, light is thought of as always traveling in straight lines, but in reality, light waves tend to bend around nearby barriers, spreading out in the process. This phenomenon is known as diffraction and occurs when a light wave passes by a corner or through an opening. Diffraction plays a paramount role in limiting the resolving power of any lens.

Doublet

Doublet is a lens design comprised of two elements grouped together. Sometimes the two elements are cemented together, and other times they are separated by an air gap. Examples of this type of lens include achromatic close-up lenses.

Dynamic range

Dynamic range is the maximum range of tones, from darkest shadows to brightest highlights, that can be produced by a device or perceived in an image. Also called tonal range.

Resolving power

Resolving power is the ability of a lens, photographic emulsion or imaging sensor to distinguish fine detail. Resolving power is expressed in terms of lines per millimeter that are distinctly recorded in the final image.

Vignetting

Vignetting is the darkening of the corners of an image relative to the center of the image. There are three types of vignetting: optical, mechanical, and natural vignetting.

Optical vignetting is caused by the physical dimensions of a multi-element lens. Rear elements are shaded by elements in front of them, which reduces the effective lens opening for off-axis incident light. The result is a gradual decrease of the light intensity towards the image periphery. Optical vignetting is sensitive to the aperture and can be completely cured by stopping down the lens. Two or three stops are usually sufficient.

Mechanical vignetting occurs when light beams are partially blocked by external objects such as thick or stacked filters, secondary lenses, and improper lens hoods.

Natural vignetting (also known as natural illumination falloff) is not due to the blocking of light rays. The falloff is approximated by the "cosine fourth" law of illumination falloff. Wide-angle rangefinder designs are particularly prone to natural vignetting. Stopping down the lens cannot cure it.

Flare

Bright shapes or lack of contrast caused when light is scattered by the surface of the lens or reflected off the interior surfaces of the lens barrel. This is most often seen when the lens is pointed toward the sun or another bright light source. Flare can be minimized by using anti-reflection coatings, light baffles, or a lens hood.

Ghosting

Glowing patches of light that appear in a photograph due to lens flare.

Retrofocus design

Design with negative lens group(s) positioned in front of the diaphragm and positive lens group(s) positioned at the rear of the diaphragm. This provides a short focal length with a long back focus or lens-to-film distance, allowing for movement of the reflex mirror in SLR cameras. Sometimes called an inverted telephoto lens.

Anastigmat

A photographic lens completely corrected for the three main optical aberrations: spherical aberration, coma, and astigmatism.

By the mid-20th century, the vast majority of lenses were close to being anastigmatic, so most manufacturers stopped including this characteristic in lens names and/or descriptions and focused on advertising other features (anti-reflection coating, for example).

Rectilinear design

Design that does not introduce significant distortion, especially ultra-wide angle lenses that preserve straight lines and do not curve them (unlike a fisheye lens, for instance).

Focus shift

A change in the position of the plane of optimal focus, generally due to a change in focal length when using a zoom lens, and in some lenses, with a change in aperture.

Transmittance

The amount of light that passes through a lens without being either absorbed by the glass or being reflected by glass/air surfaces.

Modulation Transfer Function (MTF)

When optical designers attempt to compare the performance of optical systems, a commonly used measure is the modulation transfer function (MTF).

The components of MTF are:

The MTF of a lens is a measurement of its ability to transfer contrast at a particular resolution from the object to the image. In other words, MTF is a way to incorporate resolution and contrast into a single specification.

Knowing the MTF curves of each photographic lens and camera sensor within a system allows a designer to make the appropriate selection when optimizing for a particular resolution.

Veiling glare

Lens flare that causes loss of contrast over part or all of the image.

Anti-reflection coating

When light enters or exits an uncoated lens approximately 5% of the light is reflected back at each lens-air boundary due to the difference in refractive index. This reflected light causes flare and ghosting, which results in deterioration of image quality. To counter this, a vapor-deposited coating that reduces light reflection is applied to the lens surface. Early coatings consisted of a single thin film with the correct refractive index differences to cancel out reflections. Multi-layer coatings, introduced in the early 1970s, are made up of several such films.

Benefits of anti-reflection coating:

Circular fisheye

Produces a 180° angle of view in all directions (horizontal, vertical and diagonal).

The image circle of the lens is inscribed in the image frame.

Diagonal (full-frame) fisheye

Covers the entire image frame. For this reason diagonal fisheye lenses are often called full-frame fisheyes.

Extension ring

Extension rings can be used singly or in combination to vary the reproduction ratio of lenses. They are mounted between the camera body and the lens. As a rule, the effect becomes stronger the shorter the focal length of the lens in use, and the longer the focal length of the extension ring.

View camera

A large-format camera with a ground-glass viewfinder at the image plane for viewing and focusing. The photographer must stick his head under a cloth hood in order to see the image projected on the ground glass. Because of their 4x5-inch (or larger) negatives, these cameras can produce extremely high-quality results. View cameras also usually support movements.

135 cartridge-loaded film

43.27 24 36
  • Introduced: 1934
  • Frame size: 36 × 24mm
  • Aspect ratio: 3:2
  • Diagonal: 43.27mm
  • Area: 864mm2
  • Double perforated
  • 8 perforations per frame

120 roll film

71.22 44 56
  • Introduced: 1901
  • Frame size: 56 × 44mm
  • Aspect ratio: 11:14
  • Diagonal: 71.22mm
  • Area: 2464mm2
  • Unperforated

120 roll film

79.2 56 56
  • Introduced: 1901
  • Frame size: 56 × 56mm
  • Aspect ratio: 1:1
  • Diagonal: 79.2mm
  • Area: 3136mm2
  • Unperforated

120 roll film

89.64 56 70
  • Introduced: 1901
  • Frame size: 70 × 56mm
  • Aspect ratio: 5:4
  • Diagonal: 89.64mm
  • Area: 3920mm2
  • Unperforated

220 roll film

71.22 44 56
  • Introduced: 1965
  • Frame size: 56 × 44mm
  • Aspect ratio: 11:14
  • Diagonal: 71.22mm
  • Area: 2464mm2
  • Unperforated
  • Double the length of 120 roll film

220 roll film

79.2 56 56
  • Introduced: 1965
  • Frame size: 56 × 56mm
  • Aspect ratio: 1:1
  • Diagonal: 79.2mm
  • Area: 3136mm2
  • Unperforated
  • Double the length of 120 roll film

220 roll film

89.64 56 70
  • Introduced: 1965
  • Frame size: 70 × 56mm
  • Aspect ratio: 5:4
  • Diagonal: 89.64mm
  • Area: 3920mm2
  • Unperforated
  • Double the length of 120 roll film

Shutter speed ring with "F" setting

The "F" setting disengages the leaf shutter and is set when using only the focal plane shutter in the camera body.

Catch for disengaging cross-coupling

The shutter and diaphragm settings are cross-coupled so that the diaphragm opens to a corresponding degree when faster shutter speeds are selected. The cross-coupling can be disengaged at the press of a catch.

Cross-coupling button

With the cross-coupling button depressed speed/aperture combinations can be altered without changing the Exposure Value setting.

M & X sync

The shutter is fully synchronized for M- and X-settings so that you can work with flash at all shutter speeds.

In M-sync, the shutter closes the flash-firing circuit slightly before it is fully open to catch the flash at maximum intensity. The M-setting is used for Class M flash bulbs.

In X-sync, the flash takes place when the shutter is fully opened. The X-setting is used for electronic flash.

X sync

The shutter is fully synchronized for X-setting so that you can work with flash at all shutter speeds.

In X-sync, the flash takes place when the shutter is fully opened. The X-setting is used for electronic flash.

Unable to follow the link

You are already on the page dedicated to this lens.

Cannot perform comparison

Cannot compare the lens to itself.

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.

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

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),

where:

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

Mount

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, Leica, Nikon, Pentax, Sony etc.) are always incompatible. In addition to the mechanical and electrical interface variations, the flange focal distance (distance from the mechanical rear end surface of the lens mount to the focal plane) is also 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.

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.

Speed

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. Magnification is expressed as a ratio. 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".

Manual focus override in autofocus mode

Allows to perform final focusing manually after the camera has locked the focus automatically. Note that you don't have to switch camera and/or lens to manual focus mode.

Manual focus override in autofocus mode

Allows to perform final focusing manually after the camera has locked the focus automatically. Note that you don't have to switch camera and/or lens to manual focus mode.

Electronic manual focus override is performed in the following way: half-press the shutter button, wait until the camera has finished the autofocusing and then focus manually without releasing the shutter button using the focusing ring.

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.

Fixed diaphragm

The aperture setting is fixed at F/ on this lens, and cannot be adjusted.

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.

Weight

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 lens element over multi-coatings.

Filters

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.

Teleconverters

Teleconverters increase the effective focal length of lenses. They also usually maintain the closest focusing distance of lenses, thus increasing the magnification significantly. A lens combined with a teleconverter is normally smaller, lighter and cheaper than a "direct" telephoto lens of the same focal length and speed.

Teleconverters are a convenient way of enhancing telephoto capability, but it comes at a cost − reduced maximum aperture. Also, since teleconverters magnify every detail in the image, they logically also magnify residual aberrations of the lens.

Lens caps

Scratched lens surfaces can spoil the definition and contrast of even the finest lenses. Lens covers are the best and most inexpensive protection available against dust, moisture and abrasion. Safeguard lens elements - both front and rear - whenever the lens is not in use.