Exakta RTL 1000

35mm MF film SLR camera

Specification

Production details:
Announced:1969
System: Exakta (1936)
Format:
Maximum format:35mm full frame
Film type:135 cartridge-loaded film
Mount and Flange focal distance:Exakta [44.7mm]
Shutter:
Type:Focal-plane
Model:Mechanical
Speeds:8 - 1/1000 + B
Exposure:
Exposure metering:None
Exposure modes:Manual
Physical characteristics:
Weight:645g
Dimensions:142x96x49mm

Manufacturer description #1

34 years after inventing the World's First 35mm SLR Exakta proudly announces

The Rebirth of the S.L.R.

RTL 1000 by Exakta

Radically new. Truly modern. Sleek, streamlined. The feel of lightweight efficiency. Embodies new creative capabilities. Yet retains the classic Exakta quality. Unmatched features that endured through the years. Like the exceptional range of shutter speeds (from 8 sec. to 1/1000 sec.), slow speeds, delayed action selftimer. Or the unbelievable choice of interchangeable finders, focusing screens and accessories. The incredible selection of lenses...

World's Most Versatile Camera.

The RTL 1000 features an interchangeable TTL meter COUPLED to shutter speeds. Measures entire focusing screen at shooting aperture. An ingenuous auto diaphragm mechanism, so you can use all new "internal release" automatic lenses. And all the older "external release" automatics. You get right hand and left hand shutter releases. A superb 50mm F1.8 Meyer Oreston lens. Many other technical refinements, too numerous to list.

The RTL 1000 - magnificent precision, rugged dependability! Perfect system for the advanced amateur and the pro, for the scientist, the physician. Solves the most challenging problems. And you'd expect to spend much more, yet the RTL retails for under $250.00.

Manufacturer description #2

The EXAKTA RTL 1000, maintaining the use of the world-renowned quick-change bayonet and offering plenty of valuable innovations to up-to-date miniature photography, continues the great traditions of this high-performance camera. These innovations are based on the well-approved principle of the true single-lens reflex camera with its always parallax-free correspondence of reflex image and photograph. These are the most important features of your EXAKTA RTL 1000:

SimpIe arrangement of all operating controls. Interchangeable viewfinder systems: Finder Hood, Penta Prism, and TTL Penta Prism for the automatic exposure timing with internal measurement, the lens being stopped down or fully opened. Focal-plane shutter made of metal laminae and destined for the complete series of shutter speeds from 8 seconds to 1/1000 second, 1 second to 1/1000 second with built-in delayed-action release. B setting for any long shutter speeds. Right-hand and left-hand release. Quick tensioning with a 30° preliminary elevation for series of photographs. Instant return mirror. Synchronising switch for electronic flash units and flashbulbs: electronic flash units being synchronized with approximately 1/125 second, fast-burning flashbulbs with 1/30 second. Automatic film loading system with free selection of film. Frame counter automatically returning to its initial position. Rewind release catching in. Interchangeable lenses with original EXAKTA quickchange bayonet and automatic diaphragm mechanism with internal release. On the left-hand release there can be employed any earlier EXAKTA lenses with automatic diaphragm mechanism. Accessories for any field of application.

Manufacturer description #3

For more than three decades, the EXAKTA has been characterized as the prototype of the versatile 35 mm reflex camera, as the camera of the serious amateur, of the professional, of the scientist. The EXAKTA RTL 1000, too, is marked by these qualities. Its range of applicablity is even wider still, owing to notable innovations in design and a greater variety of accessories offered for selection. However - and now comes the decisive factor in this altogether newly developed reflex camera - considering all its versatility it is, far more than its predecessors, the camera for everyone, extremely reliable, and simple to operate. With automatic exposure control, automatic film loading, the newly designed automatic diaphragm, and other refinements for action shooting, it is fashioned for the photographer of our time. The EXAKTA RTL 1000 meets his exacting demands, it helps him to avoid making mistakes in operation, yet it requires but a minimum of attention. As a genuine EXAKTA it has, of course, remained true to its system: The unchanged, original quick-change bayonet fitting permits using the well-known accessories and all the previous lens models, and single-lens reflex focusing ensures at all times parallax-free conformity of finder image and final picture.

The most significant features of the EXAKTA RTL 1000 are:

  • Genuine single-lens reflex camera 24 x 36 mm.
  • Three interchangeable viewfinders: Finder hood, prism viewfinder, and TTL prism attachment coupled to speed-setting knob for automatic exposure control, permitting internal metering with the lens stopped down or at full aperture.
  • Metal-bladed focal-plane shutter for a continuous range of speeds from 8 secs. to 1/1000 sec. and B. Self-timer from 1 sec. to 1/1000 sec.
  • Rapid wind lever with 15 degree advance stroke for serial shots. Right-hand release. Connecting point on left side of camera for lenses with automatic diaphragm and external release, connection for cable release. Instant return mirror.
  • Synchronization for flash exposures: electronic flash at approximately 1/125 sec., bulbs for short flash duration at 1/30 sec.
  • Accessory shoe for flash units with direct contact.
  • Automatic film loading system with free selection of fiIm. Self-zeroing frame counter. Click-in rewind release knob. Rewind crank.
  • Interchangeable lenses with original EXAKTA quick-change bayonet mount and internally operating automatic, also disconnectable, pressure diaphragm which, by means of a control mechanism in the EXAKTA RTL 1000, is converted into the higher grade automatic spring diaphragm.
  • Automatic diaphragm of previous EXAKTA lenses may be used.
  • Special-purpose lenses with focal lengths from 20 mm to 1000 mm.

TTL metering always gives correct exposure results

The highly developed EXAKTA RTL 1000 guides you into photographic territories that you have perhaps never entered before. But how reassuring it is to know that you will always get correctly exposed pictures if you take advantage of the automatic exposure control system in this way: Direct the EXAKTA RTL 1000, equipped with the coupled TTL prism attachment, towards your subject, rotate either the diaphragm setting ring of the camera or the speed setting dial of the TTL prism attachment until the meter needle visible in the viewfinder image centres on the index circle, then actuate the shutter release. Extremely simple, and yet absolutely reliable, since the TTL prism attachment works in accordance with the principle of internal metering through the lens. Only the light used in composing the picture is measured. The resulting values are accurate, even in connection with special-purpose lenses (image angle = metering angle), and with extension equipment and filters (automatic compensation for exposure factors). Beside the luminous density of the subject, film speed and pre-set diaphragm, or shutter speed, are, of course, taken into account. You may take the reading with the lens closed down or at full aperture.

Technical features of the TTL Prism Attach ment: Integrating system of ligth metering. Thus ensuring correct valuation of subject brightness. No decrease in brightness of finder image. Sensitivity range comprises 13 exposure values. Luminous density measurable from 4 apostilbs at f/2 up to the highest values. Bridge circuit guards against effects caused by voltage fluctuation. Mercury oxide battery (Mallory PX 13 or similar type with 1.35 V nominal Voltage).

Three viewfinder systems ensure maximum image sharpness

The extreme adaptability of the EXAKTA RTL 1000 results from the possibility of exchanging the finder systems. For modern, expressive photography, you will certainly prefer using the prism viewfinder or, better still, the TTL prism attachment, both revealing an upright, laterally correct finder image. However, when working with tripod, copying stand, microscope, or similar means of fixing the camera, in exposing below or above eye level, also in candid photography, you will appreciate the remarkable qualities of the finder hood. The viewfinders can be exchanged in an instant. Normally, you will use each one of the viewfinders with the approved focusing system - a brilliant Fresnel lens with microprism screen and groundglass circle -. You will be delighted, when viewing and selecting your picture area, to observe the bright, powerfully magnified finder image. But to achieve utmost definition, you have, above all, the groundglass field, and the microprism screen with its striking effects of unsharpness and fuzziness. The focusing system itself is interchangeable, too, so that, for instance in extreme close-up work or in photomicrography, special focusing screens may be inserted. These are available in clear glass with hairline cross, with clear centre spot and hairline cross, or with auxiliary lines, thus greatly facilitating accurate composition in specialized fields of photography.

Shutter speed settings from 1/1000 sec. to 8 sec.

At either one of these speeds, even allowing for extreme demands, approximately 98 % of your pictures will be correctly exposed. This figure includes every subject from the exciting sports shot up to night and indoor exposures. And for the last 2 %, the longer time exposures, you employ the B setting of your EXAKTA RTL 1000. You have at your disposal the newly developed, vertically running metal-bladed focal-plane shutter. Its outstanding feature is extreme dependability, while it is perfectly easy and ready to operate. The most frequently used shutter speeds, from 1/1000 sec. to 1 sec. are continuously arranged around a setting dial with click stops. An extra slow-speed mechanism makes it possible, in unfavourable lighting conditions, to work at settings of 2 sec., 4 sec., or 8 sec.

The shutter release is on the right-hand side of the camera in convenient finger-tip position and can be locked against inadvertent tripping. A cable-release connection is on the left-hand side of the camera. Also, the EXAKTA RTL 1000 has a built-in self-timer with a release knob of its own: Everyone of the shutter speeds from 1/1000 sec. to 1 sec. may be used with the delayed-action device running for about 10 secs.

The shutter is immediately recocked by means of the rapid wind lever. For ultra rapid sequence in serial shots, you will save time by setting the cocking lever to a 15° advance stroke. Owing to the instant return mirror in the EXAKTA RTL 1000, the viewfinder image is continuously visible except for the moment of the exposure. Having released your shutter, you can immediately check the effect of your exposure and decide if it seems advisable to take a second shot. A signal in the viewfinder image reminds you if the shutter has to be cocked.

Synchronization of electronic flash at 1/125 sec.

In the EXAKTA RTL 1000, the shutter speed to be set for the use of electronic flash units is 1/125 sec. The applicability of this most important light source has thus been increased to a very great extent. Blurred double images, due to motion, will no longer appear, even under relatively bright general lighting conditions, and flash can be used in addition to daylight more frequently. - Owing to the high speed of the shutter blades the EXAKTA RTL 1000 has been equipped with only one synchro switch.

Thus, there is only one flash socket, and the necessary adjustment of the shutter speed setting knob is made according to two symbols. Electronic flash, as already mentioned, at approximately 1/125sec. (symbol ↯), bulbs for short flash duration 1/30 sec. (symbol BULB). The flash units can be attached directly to the camera by means of an accessory shoe also equipped to accept the centre contact.

Film loading presents no problem whatever

The comprehensive assortment of 35 mm film in standard commercial cartridges may be used unrestrictedly in the EXAKTA RTL 1000. The decisive factor, however, is that all these films provide the conveniences of automatic film loading. All that is left for the camera user to do, is quick and easy work: Opening the camera back (simple unlocking device), inserting the cartridge, moving the film across to the marking point and under the supporting plate, closing the camera back, cocking the shutter and releasing it until the exposure counter, which jumps to zero when the camera back is opened, stands on "1". Thus, the EXAKTA RTL 1000 is ready for action. When the whole of your film is exposed, you just depress the rewind release, which clicks in, and wind the film back into the cartridge by means of the sturdy rewind crank. That is really all that camera and film require of you. Film type indicator and film speed indicator may be set to remind you which negative material you have loaded.

Please note the handsome, convenient styling of the small light-metal body, also the neatly designed, simple arrangement of all control parts. This is a camera that you can be proud of!

Every refinement in optical equipement

A high-class camera, high-class lenses - how could it be otherwise? That is why none but carefully selected, branded lenses are offered to go with the EXAKTA RTL 1000. They are exchangeable in an instant, and meet every requirement, optically and mechanically. Their highly valued qualities will mean much to you in practical work, so, for instance, utmost definition and good contrast effect, colour fidelity, helical focusing, depth-of-field scale, the original EXAKTA quick-change bayonet mount, and automatic diaphragm control. Especially worth mentioning is the fact that the EXAKTA RTL 1000 utilizes newly developed lens models with internally operating automatic, but also disconnectable, pressure diaphragm which, by means of a control mechanism in the camera, is converted into the higher grade spring diaphragm. This makes picture taking far simpler and more accurate. The range of hitherto familiar EXAKTA lense is, of course, still applicable. With the aid of an extension piece, the automatic diaphragm with external release mechanism can be actuated without limitation from the coupling point on the left-hand side of the camera. Special-purpose lenses with focal lenghts from 20 mm to 1000 mm are available, up to 300 mm with automatic diaphragm. Extreme telephoto objectives may be fitted to the outer bayonet rim of the EXAKTA RTL 1000 and they give full coverage of the image field without any vignetting effect.

From the Modern Photography magazine (December 1970)

The 1000RTL is a brand-new camera design which uses the Exakta bayonet mount and accepts all old interior bayonet, automatic diaphragm or manual Exakta lenses. Aside from the mount, no part of it has any resemblance to the old trapezoidal 1936 design. The automatic diaphragm mechanism for the new lenses is internal, it has a right-hand operating rapid-wind lever, right-hand shutter release (with additional left-hand release), an interchangeable behind-lens meter prism which is semicoupled to the shutter-speed dial, measuring the entire focusing screen.

By twirling, aligning, and pressing tiny odd controls on the prism housing you can set the shutter speed yourself, line up the meter needle in the finder at full aperture, determine the right opening from the meter dial and then set the aperture on the camera lens itself. If this seems awkward, you can twist a few more odd controls and make readings at actual shooting aperture, but unlike all other SLR's using such as system, there is no convenient lever which stays in place and no large button to press. You have to set the camera lens on manual control with a little turn lever on the lens mount or push in on a small integral depth-of-field preview lever for which you must fumble while camera is at eye level.

The new metal shutter sounds like a Copal, syncs electronic flash like a Copal at 1/125 sec. and has the excellent accuracy of the Copal.

While there are no 26 speeds to 12 sec. as per the old Exaktas, there are the usual 1 to 1/1000 sec. set conveniently by a dial atop the camera and additional speeds of 2, 4 and 8 sec. built into a separate self-timer.

Although the metering system is awkward and clumsy (but there!), all isn't tears and wringing of hands. The camera is nicely shaped with a slightly bowed front, a very excellent large front shutter release lever, a good quick loading system which seems to be the one all East German cameras will adopt. The central microprism is a very good one, the surrounding fine-focusing collar excellent and the whole finder reasonably bright. The meter reads down to 1/8 sec. at maximum aperture with an ASA 400 film.

The 50mm f/1.8 Oreston is a very good one. It's nicely mounted, well finished, with very good, clear controls and it focuses down to 14 in. All the other Exakta lenses are available and if you can stand that external automatic diaphragm arm, you can get by O.K.

From the editor

The following "internal release" automatic lenses were produced for the Exakta RTL 1000:

***

The weight and dimensions are indicated for the camera body with the finder hood.

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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.