smc Pentax 6×7 75mm F/4.5 Shift

Shift lens • Film era • Discontinued

Abbreviations

SMC Multi-layer anti-reflection coating is applied to the surfaces of lens elements. This anti-reflection coating increases light transmission, eliminates flare and ghosting, and maintains color consistence among all lens models.
SHIFT Perspective Control.

Model history (2)

smc Pentax 6×7 75mm F/4.5 ShiftP9 - 80.70mB82 1979 
smc Pentax 67 75mm F/4.5 ShiftP9 - 80.70mB82 1989 

Features highlight

6x7
Shift 0..20mm
Lens rotation
MF
Preset
10 blades
B82
filters
Gelatin filters

Specification

Production details:
Announced:1979
Production status: Discontinued
Original name:ASAHI OPT. CO. SMC PENTAX-6X7 SHIFT 1:4.5 75mm
System:Pentax 6×7 (1969)
Optical design:
Focal length:75mm
Speed:F/4.5
Maximum format:Medium format 6x7
Mount and Flange focal distance:Pentax 6x7 [84.95mm]
Diagonal angle of view:60.9°
Lens construction:9 elements in 8 groups
Diaphragm mechanism:
Diaphragm type:Preset
Aperture control:Preset ring + Aperture ring
Number of blades:10 (ten)
Focusing:
Closest focusing distance:0.7m
Magnification ratio:1:7.14 at the closest focusing distance
Focusing modes:Manual focus only
Manual focus control:Focusing ring
Perspective control mechanism:
Shift range:0..20mm
Tilt range:Not available
Lens rotation:Yes
Tilt/Shift rotation:-
Physical characteristics:
Weight:950g
Maximum diameter x Length:⌀97×106.5mm
Accessories:
Filters:Bayonet-type 82
Additional features:Rear gelatin filter holder
Lens hood:Not available
Teleconverters:<No data>
Sources of data:
1. Pentax 6x7 system booklet.
2. Pentax 6x7 system booklet (II).
3. Pentax 6x7 interchangeable lenses operating manual (PUB. 06361) (May 1984).
4. Pentax cameras booklet (PUB. 06091, 40 pages) (March 1987).
5. Pentax SLR cameras booklet (PUB. 050101) (September 1988).

Manufacturer description #1

Designed for the professional in architectural photography, this unique lens features a continuously variable shift movement up to 20mm off axis for complete control over the degree of correction plus a full 360 lens barrel rotation. Exclusive Super-Multi-Coating minimizes flare and enhances resolution, contrast and color balance.

Filter size: 82mm threaded or bayonet. Gelatin filter holder in rear section of mount.

Manufacturer description #2

Your SMC Pentax 6x7 75mm shift lens is of great value for architectural, scenic and general purpose photography as well. Corresponding roughly to a 35mm lens in the 35mm format, it has the capability of correcting converging lines by making them perpendicular. lt features full 360-degree barrel rotation and offers a maximum shift of 2Omm, enabling creation of virtually an infinite variety of perspectives. You not only have the choice of correcting, but also of "over-correcting" or not correcting the subject in order to produce the most pleasing, striking or dramatic effect. Moreover, the precise shift capability of the lens makes it possible to create sweeping double-negative panoramas by joining together two corrected and perfectly matched negatives.

I. Operating the Shift Lens

For critical photography such as architecture, precise results and the most pleasing effects are obtained if shifts are made with the lens perpendicular to the film plane or tilted slightly upwards. For this reason, and due to the weight of the camera, use of a tripod is recgmmended. The lens may be mounted either vertically or horizontally to the tripod but a sturdy model should be used to prevent camera movement which causes misalignment.

Lens Rotation: The lens rotates a full 360 degree via the lens rotation ring. Click-stops are pvovided for every 3O degrees of rotation and inbetween settings may also be used. The green dot in front of the rotation ring indicates the direction in which the lens will shift as you turn the ring. With the dot at the top, the lens will shift upward (simultaneously the image in the viewfinder will move downward); with the dot at the bottom, the lens moves downward and the image upward; when the dot is located 90 degrees to the left, the lens moves horizontally to the left, etc.

Shifting: Because the lens rotates fully, two shift scales (with clickstops at 1 millimeter intervals) are provided to facilitate checking the degree of shift. As you turn the shift ring the amount of shift is indicated by the white index dot on the shift scale.

II. Correcting for Converging Lines

When set for zero millimeters shift, the shift lens will function as a normal 75mm wide-angle lens. Thus, when tilted upward, lines will converge at the top, conversely, when the lens faces downward (as when photographing from the top of a tall building) lines will converge at the bottom; when the camera is level lines will converge to the right or left in accordance with the direction the lens is moved off a perpendicular axis from the subject.

Whenever desiring to correct for converging lines, the lens must be shifted in the direction in which the lines converge. lf the lines appear to converge at the top as when photographing a tall building, for example, proceed as follows:

1. Turn the lens rotation ring so that the green dot is facing upward (the same applies whether the camera is mounted horizontally or vertically on the tripod).

2. Sight the subject through the viewfinder and slowly rotate shift ring counterclock- wise. As the shift ring is rotated, the lens will shift upward and the image in the viewfinder will simultaneously move downward.

3. Recenter the image in the viewfinder (you will find that the lines no longer converge to the same extent). Continue shifting the lens and recentering the image until the lines appear perpendicular.

Notes: When the desired shift cannot be obtained at maximum 2Omm shift, tilt the camera upward so that the axis inclines slightly; this will enable you to include the subject in the viewfinder, although lines will not be perfectly perpendicular. lf greater correction is still desired, back away from the subject to the point where where the desired correction can be obtained with the optical axis remaining perpendicular to the subject (excess can be trimmed later during enlarging).

Aperture Setting: Although the 6x7 shift lens does not feature an automatic diaphragm, it features convenient open-aperture viewing by means of the combined use of a special preset ring in conjunction with the aperture ring. First, preset the shooting aperture, f/11 for example, on the preset ring by aligning f/11 with the aperture index dot. Then, set the aperture ring to f/4.5 for bright viewing. Next, after focusing and composing, rotate the aperture ring to the right until it stops in line with the preset ring. Now, proceed by making a stopped down exposure measurement and taking the picture.

Note: Shifting up until the point of shutter release should be carried out at open aperture. Because of the effects of shifting, shooting apertures when the lens is stopped down should be f/8 or f/11 or as near to these as possible. Conversely, if the lens is stopped down farther (to f/16, f/22, etc.) some loss of sharpness will result because of defraction during shifting.

Exposure Measurement: Exposure will vary in accordance with the extent and direction of shift. Moreover, when the lens is shifted, the sensitivity of the exposure needle differs slightly from normal. To compensate for this, with the camera mounted horizontally, underexpose 1/2 stop; conversely, with the camera mounted vertically, overexpose 1/2 stop. Another method is to frame the subject first and take the exposure reading, then make appropriate compensation for shifting. Because shooting conditions vary from photo to photo, your own experience will produce the best results in compensating for lens shift.

III. "Emphasizing and Overcorrecting"

In addition to correcting for converging lines at the top by shifting the lens upward, the shift lens can also be shifted downward (reverse shift) to emphasize or exaggerate the degree to which lines converge; for example, to apparently increase the height of a tall building, or the length of a models legs. Moreover, when an 8mm upward shift is required to make the converging lines of a building appear perpendicular, an overshift of 15mm will cause the lens to converge in the opposite direction for different emphasis. By employing the various shifting techniques, one can create new perspectives in order to achieve the most dramatic and pleasing effect.

IV. Panoramics

Sweeping panoramics in which the picture format is effectively doubled horizontally from 6 x 7 to 6 x 14 are easily created with the SMC Pentax 75mm shift lens. Panoramics appear most attractive when made in the horizontal format; thus, the camera should be mounted to the tripod horizontally. Also, keep the camera perfectly level if you desire to keep lines from converging.

1. Shift the lens completely (20mm) to the left, and make the first exposure.

2. Next, rotate the lens 180 degrees so that the 20mm shift is on the right, and make the second exposure (rotating the lens and advancing the film should be carried out as gently as possible to prevent camera movement, which will result in mismatching of the two photographs).

3. Prints can later be made from the two negatives. The portions which overlap are removed, forming two perfectly matched negatives which are joined together to make one panoramic view.

Filters

In addition to accepting both 82mm screw-in type and bayonet-type filters which fit over the front of the lens, the 6 x 7 shift lens also features a gelatin filter clip at the rear which accepts gelatine filter squares, trimmed to size and inserted.

Other shift lenses in the Pentax 6×7 system

Pentax 6x7 mount (1)
smc Pentax 67 75mm F/4.5 ShiftP9 - 80.70mB82 1989 
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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.

MF

Sorry, no additional information is available.

Lens rotation

By using rotation, the direction of the entire lens can be switched.

Tilt/Shift rotation

By using Tilt/Shift rotation, the relationship of the tilt and shift operation directions can be switched from right angle to parallel.

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, Nikon, Pentax, Sony etc.) are always incompatible. In addition to the mechanical and electrical interface variations, the flange focal distance can also be different.

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

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 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/4.5 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 and/or rear lens elements 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.