Pentax K-7

APS-C AF digital SLR camera

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Specification

Production details:
Announced:May 2009
System: Pentax K APS-C (2003)
Format:
Maximum format:APS-C
Imaging sensor:23.4 × 15.6mm CMOS sensor
Resolution:4672 × 3104 - 15 MP
Crop factor:1.54x
Sensor-shift image stabilization:Yes
Mount and Flange focal distance:Pentax K [45.5mm]
Shutter:
Type:Focal-plane
Model:Electronically controlled
Speeds:30 - 1/8000 + B
Exposure:
Exposure metering:Through-the-lens (TTL), open-aperture
Exposure modes:Programmed Auto
Aperture-priority Auto
Shutter-priority Auto
Manual
Physical characteristics:
Weight:670g
Dimensions:130.5x96.5x72.5mm

Manufacturer description

May 19, 2009: HOYA CORPORATION PENTAX Imaging Systems Division is pleased to announce the launch of the PENTAX K-7 lens-interchangeable digital SLR camera. Despite its compact, lightweight body, this new model brings together a wide array of advanced functions and user-friendly features with outstanding reliability and operability. This makes it possible to enjoy high-quality digital SLR photography with great ease.

The K-7 has been developed as a high-end model of the PENTAX K digital SLR camera series. True to its series concept, it was designed not only to assure outstanding image quality, but also to provide exceptional ease and comfort of operation and the utmost satisfaction to photo enthusiasts of all levels, including advanced amateurs. After making a thorough review of all essential digital SLR camera components and functions, PENTAX has revised and upgraded many of them, including viewfinder, shutter unit, continuous-shooting capacity, and exposure and autofocus systems. Protected by a durable, high-quality metallic body, but the K-7 is designed to be extremely compact and functional — just like all other K-series models — for enhanced portability and maneuverability. In addition, it has added several user-friendly features, including video recording, high dynamic range (HDR), and automatic horizon correction. All of these make the K-7 a tremendous photographic tool, perfect for all discerning digital SLR photographers.

Major Features

Durable and functional body, smaller than any other in its class

The K-7 is built exceptional solid and durable, as its chassis is made of high-rigidity stainless-steel alloy and its housing is made of durable but lightweight magnesium-steel alloy. Thanks to 77 special seals applied to the body, it also features a dustproof, weather- and cold-resistant construction, assuring reliable operation even under harsh conditions and at a temperature as low as -10°C. It also features a newly designed shutter unit providing a top shutter speed of 1/8000 second and the outstanding durability to withstand 100,000 shutter releases. Despite all these features, the K-7 is one of the most compact and functional mid-class models in the market, because PENTAX applied all the experience and expertise in camera downsizing the company has developed from the earliest days of film-format SLR cameras.

Optical viewfinder showing nearly 100% field of view

The K-7’s glass prism finder offers an approximately 100% field of view and an approximately 92% magnification to facilitate focusing and framing operations. It also features a new Natural-Bright-Matte III focusing screen to improve focusing accuracy during manual-focus operation.

High-speed continuous shooting at approx. 5.2 images per second

The K-7’s high-speed continuous shooting mode captures as many as 40 images (in JPEG recording format) at a maximum speed of approximately 5.2 images per second, allowing the photographer to follow the movement of an active subject or preserve a sequence of the subject’s expressions.

New DR II mechanism to minimize dust spots

The K-7 comes equipped with the newly developed DR (Dust Removal) II mechanism, designed to effectively minimize annoying dust spots on recorded images, even after changing lenses in dust-prone outdoor settings. By shifting the low-pass filter located in front of the CMOS image sensor at supersonic speed using a piezoelectric element, it shakes the dust off the low-pass filter as effectively and efficiently as any other dust removal device. The K-7’s unique dust-alert system also lets the user check for dust adhering to the low-pass filter prior to actual shooting.

High-quality image reproduction

Approximately 14.6 effective megapixels for true-to-life image reproduction

The K-7 incorporates a newly developed CMOS image sensor measuring 23.4mm by 15.6mm and featuring a high-speed, four-channel image data readout. With approximately 14.6 effective megapixels, this image sensor can faithfully and accurately reproduce fine-detailed, gradation-rich images. With the adverse effects of digital noise greatly reduced, the sensitivity can be increased from ISO 100 up to the highest level of ISO 6400 (via a custom function) without worry.

High-performance, high-speed PRIME II imaging engine

The K-7 features the newly developed PRIME (PENTAX Real Image Engine) II, an upgrade of the original PRIME, as its imaging engine. This new imaging engine offers greater data-processing speed and produces better-quality images with richer gradation and more accurate color rendition. It also offers high-speed movie data transmission.

New 77-segment multi-pattern metering

Newly developed for the K-7, a sophisticated 77-segment multi-pattern metering system greatly improves light-metering accuracy. By accurately analyzing various types of data (such as the image’s composition and format between upright and horizontal, and the subject’s distance and magnification) transmitted from the sensors in the camera body, this system greatly improves the accuracy of exposure control.

New-generation SR mechanism for improved shake-reduction effect

The K-7 features the PENTAX-developed SR (Shake Reduction) mechanism, which effectively compensates the adverse effect of camera shake by approximately 2.5 to four shutter steps, assuring sharp, blur-free images even under demanding shooting conditions. This innovative mechanism is compatible with all PENTAX interchangeable lenses — even most of the lenses designed for film-format cameras.* Since this new-generation version can freely shift the image-sensor unit to keep it level regardless of the camera’s inclination, it also provides such user-friendly new functions as automatic level adjustment and minute angle adjustment (in the direction of up/down, right/left and clockwise/counterclockwise), helping to compose the image exactly the way the photographer wants.

Live View real-time, on-display image confirmation with Face Recognition AF and high-speed continuous shooting modes

The K-7 features the Live View function, which allows the user to view the image on the LCD monitor during shooting. You can take advantage of this convenient function not only in the Contrast AF mode, which optimizes the focus based on the subject’s contrast, but also in the Face Recognition AF mode, which automatically and accurately focuses on the subject’s face. Thanks to the newly developed diaphragm-control mechanism, the Live View function can also be used in the continuous shooting mode with the mirror at lock-up position.

High-quality still image recording at 1280 x 720 pixels; 30-frames-per-second movie recording at HD-television proportions

The K-7 adds a new movie recording function, extending the benefits of SLR photography to the world of movie shooting: For instance, reduce the depth of field to make the subject stand out, or use different lenses to create distinctive visual effects. Beautiful movie clips can recorded at different sizes — 640 x 416 pixels, 1536 x 1024 pixels, or 1280 x 720 pixels (16:9 high-definition TV proportions) — at a frame rate of 30 frames per second. The K-7 is also equipped with an HVMI terminal and an external microphone input terminal.

New 11-point wide-frame AF sensor

The K-7’s new SAFOX VIII+ wide-frame autofocus system features 11 sensor points (with nine cross-type sensors positioned in the middle). By adding a light source type to its data range, and driven by a greatly improved algorithm, this AF system assures reliable, responsive autofocus operation superior in speed and accuracy to the previous system. The K-7 also incorporates an AF-assisting spotbeam projector in its built-in flash unit to improve autofocusing accuracy in the dark.

Custom Image function to easily create desired visual effects

The K-7’s Custom Image function lets the user control the image’s finishing touch to capture their photographic intention, or reproduce the ambience of the scene. With the K-7, the user can select one of seven modes, including the new “Muted” mode designed to recreate an image with delicate, subdued colors. In addition to saturation, tone, contrast and sharpness — the factors previously available — it is now possible to adjust “key” and “contrast highlight/shadow” to the desired levels. The effects of these factors can be effortlessly confirmed on a preview image using the Digital Preview or Live View function before finalizing the settings.

Versatile exposure system for faithful reproduction of creative intentions

Hyper Program function

The K-7’s Hyper Program function allows the user to instantly switch to the Shutter- or Aperture-Priority AE mode from the Programmed AE mode, with a simple turn of the electronic dials on the grip. To return to the Programmed AE mode, simply press the green button positioned next to the shutter release button.

Hyper Manual function

When shooting in Manual mode, a single push of the green button allows the user to instantly set the proper exposure for the subject.

Sensitivity-Priority mode

The K-7 features a unique Sensitivity-Priority (Sv) mode, which is designed to automatically select the optimum combination of aperture and shutter speed for a user-selected sensitivity. The sensitivity can be shifted instantly in 1/2 or 1/3 steps by turning the electronic dial on the back panel.

Shutter/Aperture-Priority mode

Taking full advantage of the unique capability of digital cameras permitting automatic shift of sensitivity at any time, the Shutter/Aperture-Priority (TAv) mode automatically selects the most appropriate sensitivity for a user-selected shutter-speed/aperture combination. It allows the user to experiment with a greater range of photographic expressions with great ease.

Large, easy-to-see 3.0-inch wide-view LCD monitor with approximately 920,000 dots

The K-7 features a large 3.0-inch color LCD monitor with approximately 920,000 dots on its back panel. Its wide-view design allows the photographer to check the monitor image from approximately 170 degrees both vertically and horizontally, facilitating low- and high-angle shooting using the Live View function.

Powerful rechargeable battery

The K-7 is powered by a large-capacity, rechargeable lithium-ion battery, which can capture approximately 980 images** when fully charged.

Other features

  • HDR (high dynamic range) function to create one composite image with an extra-wide gradation range from three images with different exposures
  • Dynamic-range expansion function to compensate for both white-washed (overexposed) and blacked-out (underexposed) areas
  • Digital level function for easy checking of the image’s levels
  • Automatic compensation of distortion and lateral chromatic aberration (available only with DA- and DFA-series lenses)
  • White balance control, featuring a new CTE mode to emphasize the color components of sunse t scenes and a new incandescent-tinted fluorescent light mode
  • Multi-exposure function, with a superimposition of already-recorded images on the LCD monitor for at-a-glance comparison
  • Attachment of copyright credits on recorded images
  • RAW button for single-action switching of image file format
  • 16 digital filters to add a range of visual effects; a new function to record an overwritten history also available
  • Color-specific control buttons/dials for easy recognition and quick access, based on the universal color design
  • PENTAX Digital Camera Utility 4 software package, including a RAW-data processing application (based on the popular SILKYPIX RAW-data processing engine developed by Ichikawa Soft Laboratory) and a browser application

Optional accessory

Battery Grip D-BG4

Exclusively designed for the PENTAX K-7 camera body, the Battery Grip D-BG4 is powered by either a rechargeable lithium-ion battery or six AA-size batteries. Since it supplements the camera’s battery as an additional power source, the number of recordable images is greatly increased. To facilitate vertical-position shooting, this grip features extra shutter-release button, preview lever, electronic dials, AE-lock button, Green button and AF button. It also provides the same dustproof, weather- and cold-resistant construction as the camera body itself.

Special limited editions (1)

Similar cameras (4)

APS-C • Auto focus • Digital • Singe-lens reflex • Pentax K mount

Model Shutter Metering Modes Year
Samsung GX-10 E, 1/4000 TTL • OA PASM 2006
Samsung GX-1L E, 1/4000 TTL • OA PASM 2006
Samsung GX-1S E, 1/4000 TTL • OA PASM 2006
Samsung GX-20 E, 1/4000 TTL • OA PASM 2008
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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.

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, 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 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 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.