Olympus Pen FT


Announced
Production status
System
Olympus Pen F system cameras

Olympus Pen FT

Half frame MF film SLR camera • Discontinued

Specification

Format:
Half frame
Film type:
135 cartridge-loaded film
Olympus Pen F [28.95mm]
Shutter:
Type:
Focal-plane
Model:
Mechanical
Speeds:
1 - 1/500 + B
Exposure:
Exposure metering:
Through-the-lens (TTL), open-aperture
Exposure modes:
Manual
Physical characteristics:
Weight:
600g
Dimensions:
127x69.5x62.5mm

Manufacturer description #1

The world-wide acceptance of the Olympus Pen F by both professionals and amateurs has not left the Olympus factory resting on its laurels. As part of its continuing program of Research and Development, a new improved model, the Pen FT, with a very advanced through-the-lens metering system is now available to the public.

Again Olympus has made improvements on existing single lens reflex technology without in any way compromising its commitment to compact size and minimum weight.

And because of the superior Olympus optics, negatives can be blown up to poster-size with excellent quality.

***

Olympus engineers were not content with the solutions arrived at by other manufacturers in the design of a through-the-Iens metering system. The new Olympus FT system has several advantages over the existing systems.

1) A unique aperture numbering system replaces the cenventienal and often inaccurate F/step system.

It is characteristic of through-the-lens metering system that expesure calculations are influenced by the position of the meter, the speed of the lens and the focal length of the lens. Especially when the film is exposed at the maximum aperture, the F/stops very often do not accurately reflect the proper exposure.

To eliminate this error, found in all other metering systems, Olympus has designed a numbering system, beginning with "0" and ending with "7" to replace the conventional F/stop method. This is equivalent to the "F" stop calibration favored by the most exacting professional photographers.

Using this system, the meter reads out the exact correct exposure as the light is measured through the lens, and eliminates the errors found in conventional CdS meter F/stop systems.

2) Light measurements can be made at both "wide-open aperture" and "stopped down aperture."

Measuring at "wide-open aperture" is, of course, the most convenient for the photographer. But occasionally as when extension rings or extension bellows are used, it is very helpful to use the "stopped down aperture" measurement. The Olympus aperture numbering system assures a perfect exposure in both cases.

3) Averaging light measurement system

The FT uses an extra-large CdS meter equipped with a special device to screen out extraneous light. The meter is placed near the viewfinder eyepiece in the porroprism, and averages the total amount of light reaching the film surface.

***

1. The world's most unique design in a single lens reflex

The world of photography was astonished at the first appearance of the unique Olympus Pen F. Here was a camera that was a true single lens reflex, yet had eliminated the bulky prism on top of the camera. Here was a camera that was as compact as a rangefinder camera and even smaller.

And above all, here was a camera that introduced new standards of precision and quality to the single lens reflex field.

2. Unique PORROPRISM finder system

Olympus completely changed the appearance of single lens reflex cameras. Instead of the bulky pentaprism sitting awkwardly on top of a single lens reflex camera, Olympus introduced the built-in porroprism. A horizontal rather than vertical revolving mirror is used in the camera. Automatic diaphragms are used in the interchangeable lenses, thus the view in the finder is always bright as the viewing is done at full aperture.

3. The smallest, lightest and most convenient single lens reflex camera

The Olympus Pen FT weighs only half as much as the conventional 35mm single lens reflex camera, and its size is even smaller than a rangefinder camera. The savings in weight and size are extended through a large range of accessories that are equally compact.

It permits the photographer to carry more lenses, more accessories, and yet less weight.

4. Extreme close-up photography possible without additional accessories

The Olympus Pen FT is the only camera which permits a close-up photograph to be taken as close as 14 inches. The camera is therefore very convenient for photocopying, close-up photography of persons, plants, flowers, insects, etc. The convenience of close-up photography without the use of extra accessories cannot be overemphasized.

5. Full synchronization at all shutter speeds

The unique Olympus rotary metal focal plane shutter now makes it possible to synchronize strobo lighting at all shutter speeds. There are also M and X contacts for synchronization with all types of flash equipment.

6. New type shutter developed exclusively for the Olympus FT

This new type shutter has been developed exclusively for the OLYMPUS Pen FT to make it a super small-size, super efficient camera. A high speed rotary shutter with a speed of 27 meters per second; completely different in style from all conventional focal plane shutters. This is an all metal shutter using a super thin 35/-1000mm titanium diaphragm. It is extremely resistant to change in temperature and humidity, and change with years, and has remarkable durability. The precision of the shutter speed is also high, and some of the characteristic defects of conventional focal plane shutters (image distortion when a moving object is photographed, etc.) do not exist.

7. Half-frame economy and convenience coupled with quality equal to full frame in other cameras

When Olympus first presented the half-frame size seven years ago there was some doubt that the half-frame could equal to the quality in large prints obtained with full frame 35mm cameras. But Olympus engineers based their confidence in half-frame on two significant factors: First, the half frame is closer to the basic 8 X 10 format and thus there is less cropping in half frame than full frame. Secondly, the Olympus lenses are designed with higher resolving power. The final proof of course came in the thousands of fine prints made by leading professional photographers throughout the world.

8. An amazing range of accessories

The Olympus Pen FT is part of one of the world's largest photographic camera systems. Because the lenses and accessories have been designed for the smaller half-frame format, there is considerable savings in size, weight and cost. But absolutely no compromise in quality.

Manufacturer description #2

FILM SIZE: 24x18 mm.

LENS: (with F1.2 standard lens) H Zuiko Auto S, F1.2, f=42 mm, (with F1.4 standard lens) G Zuiko Auto S, F1.4, f=40 mm, (with F1.8 standard lens) F Zuiko Auto S, F1.8, f=38 mm. All lenses have fully automatic diaphragm and are marked on Through-The-Lens numbers and F-numbers.

LENS REPLACEMENT: Bayonet system ("Pen" mount).

SHUTTER: OLYMPUS rotary metal focal-plane shutter; B. 1-1/500 sec. (equally calibrated) one-pivot non revolving shutter speed dial.

SYNCHRONIZING: All shutter speeds synchronization with M & X contacts point switch.

VIEWFINDER: Porroprism finder, magnification 0.8X (standard lens), with microprism and special Fresnel lens.

MIRROR: Horizontally opening shockless quick return mirror.

LOADING: EL (easy loading) system.

FILM ADVANCING: 1-stroke lever type with an advancing stroke angle of 150 degrees, self-cocking to prevent double advances and double exposures.

FILM COUNTER: Exposed counting, self-resetting type.

FILM REWINDING: Crank type rewind button setting system.

FOCUS ADJUSTMENT: Direct advancing helicoid system, minimum close-up distance 35cm.

EXPOSURE ADJUSTMENT: Through-The-Lens number system, both open and stopped-down aperture methods available.

LIGHT MEASURING RANGE: EV3~EV17 (ASA 100) with F1.4 standard lens.

LIGHT ACCEPTOR: Extra-large CdS meter, average light measurement method.

POWER SOURCE: Mercury battery (1.3 volts).

FILM SPEED RATING SCALE: ASA 25-400.

SELF-TIMER: Lever system (90 degrees) actuated in about 11 seconds.

REAR COVER OPERATION: "Magic" locking hinge system.

Manufacturer description #3

Introducing the new Olympus PEN FT Pro f2.8. The PEN FT has long been a favorite of photographers who discovered that this little jewel of a camera could do anything a full frame 35mm SLR camera could do, and more. Part of the enchantment was with the extensive Olympus PEN FT system - an amazing assortment of lenses and accessories, all smaller, lighter and in many cases less in cost than for other SLR cameras. Other PEN FT fans fell in love with the Zuiko lenses, which are made in Olympus' own factory and rate with the world's finest and most expensive lenses. But the outstanding feature of the PEN FT is its small size. A photographer can literally put the basic elements of an SLR system into his shoe and have room left for film.

Now the new f2.8 Zuiko lens makes the PEN FT even smaller, in fact small enough to fit into your shirt pocket. This specially designed 38mm, f2.8 Zuiko lens just barely protrudes from the camera body and compares in resolution and contrast to the best of the famous Zuiko lenses.

From the Modern Photography magazine (1970)

The superbly performing, small and convenient Olympus Pen FT, world's only half-frame single-lens reflex, now has an all-black companion model, the Olympus Pen FT PRO. Aside from the color, both cameras have identical specifications, except that the PRO is fitted with a superflat 38mm f/2.8 Zuiko lens which extends barely 1/2-in. from the camera body also making it the world's only pocketable SLR. Another advantage of the Pen's 18 x 24mm format is the very compact 50-100mm f/3.5 Zuiko zoom which fills the frame like a 70-130mm zoom on a full-frame camera.

The Pen FT engineers have incorporated a large-area CdS printed circuit meter behind one of the reflecting surfaces in the finder. The meter integrates all the light from the entire finder area. The Olympus meter pointer number scale is visible through the finder at the left of the picture area.

First you set the ASA of the film (25 to 400) in a small window on the side of the shutter speed dial. Now set your shutter speed. Look through the finder to make your meter reading. The meter scale reads in Olympus meter numbers from 0 to 7. Note the number on which the pointer rests (or point between numbers) and set this number on the aperture ring.

These numbers on the top of the aperture ring are not f/stops. If you wish to find out what f/stop the number represents you can turn the camera upside down and look at the diaphragm ring markings on the bottom.

If you'd rather make a meter reading at shooting aperture, you can do it. Just press the preview button on the lens mount and turn the diaphragm ring until the pointer inside the finder lines up with the lowest number on the lens you're using. Now you're ready to shoot.

Be not in anguish if you have any older Olympus Pen F lenses without meter numerals. You will be able to purchase adhesive numeral strips to cover your diaphragm ring.

The FT meter read within 1/2 f/stop of a known light source over its entire range. The meter can read down to f/2 at 1/15 sec. with an ASA 400 film. It is also possible to use the meter with non-Olympus manual or preset lenses.

The new microprism snaps the image in and out of focus efficiently, although the meter system has caused an overall viewing light loss of approximately 2 f/stops. However, by eliminating the outer Fresnel rings, the entire screen has been made usable for focusing.

Other Pen FT and PRO features: a single-stroke, long-armed wind lever, self-timer, quick-loading multiple slot and tooth type take-up spool.

From the Classic Camera magazine (February 2000)

The success of the Olympus Pen F was partly due to its reduced dimensions and partly to the number of shots it could take with a single roll: 40 negatives from a 20-exposure roll, or 72 negatives from one of 36 exposures. Modifying the pressure plate it was even possible to take 144 images on an extra-thin film roll of 72 exposures. The commercial success of the new, small camera was such that after only three years of production, it was decided to replace it with a model whose appearance would be the same, but updated to include a TTL-type exposure meter.

The new camera was known as the Olympus Pen FT and production began on it in October 1966. The body and main controls of the Olympus Pen FT were unchanged, but the large gothic "F" no longer appeared on the front to make way for an ingenious self-timer lever equipped with a control independent of the shutter release button. The focusing screen was also improved by making it clearer and incorporating a circle with microprisms in the center. The rapid winding lever required just a single movement for film advance and shutter tensioning.

Aside from these functional and cosmetic changes, the main feature that distinguished the Olympus Pen FT from the previous model was the TTL exposure meter. For 100 ASA film, the exposure meter of the Pen FT ranges from EV 3 to EV 17 and the reading is made at full diaphragm aperture with lenses pre-set, or at actual closing with accessories inserted between the camera body and lens. The needle seen in the viewfinder does not shift between the usual "+" and "-" or even along the shutter speed range, but rather along an index ranging from 0 to 7. To obtain the exposure level indicated by the photocell, all that is required is to set the lens diaphragm ring to the value corresponding to that shown by the needle. The metal ring of the Zuiko Auto S lens made for the Olympus Pen FT is marked with whole numbers instead of the numbers corresponding to the actual values on the diaphragm. To use old lenses with the Olympus Pen FT, all that is required is to place over the diaphragm ring a clear adhesive strip with pre-printed whole numbers so that 0 corresponds with the highest value and the number 3 with diaphragm setting 8. Clearly, the exposure meter values can be modified by also changing the selected shutter speed setting. The film setting control is coupled with the shutter speed control and can be set at between 25 and 400 ASA with markings for 50, 100 and 200 ASA and notches for intermediate values. To make a light reading with the diaphragm closed, just push the diaphragm manual closing button located on the lens barrel and adjust the shutter to the correct speed.

The Olympus Pen FT was also available in black body finish. Production of the Olympus Pen FT was interrupted suddenly in April 1971 to create room for the short-lived full-frame screw reflex Olympus FTL, production of which lasted just over 6 months to be replaced by the small Olympus OM1, compact but with full 24x36mm format. Another 18x24 format 35mm reflex did not appear until the 1988 Yashica Samurai, but without interchangeable lenses and incorporating features completely different from those found in the extraordinary Olympus Pen FT.

From the editor

The weight and dimensions are indicated for the camera body with the F1.8 standard lens.

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Copyright © 2012-2024 Evgenii Artemov. All rights reserved. Translation and/or reproduction of website materials in any form, including the Internet, is prohibited without the express written permission of the website owner.

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.