More than just a camera lens database

LENS-DB.COM

Hasselblad 205TCC

Medium format MF film SLR camera

Specification

Production details:
Announced:1991
Order No.:10405 - chrome
10413 - black
System:● Hasselblad V (1957)
Format:
Maximum format:Medium format 6x6
Film type:120 roll film
220 roll film
Mount and Flange focal distance:Hasselblad V [74.9mm]
Shutter:
Type:Focal-plane
Model:Electronically controlled
Speeds:16 - 1/2000 + B
Exposure:
Exposure metering:Through-the-lens (TTL), open-aperture
Exposure modes:Aperture-priority Auto
Manual
Physical characteristics:
Weight:1615g
Dimensions:178x118x108mm

Manufacturer description #1

The Hasselblad 205TCC is the flagship of the current Hasselblad models. It is the first Hasselblad camera with built in exposure automation for existing light and electronic flash. The camera is a true Hasselblad design which means it is compact, lightweight and compatible with the rest of the system. You can therefore add a 205TCC to your existing outfit and use with most or all your other Hasselblad system components.

But the 205TCC is also part of a new system of TCC lenses, TCC magazines, TCC extension tubes, and TCC viewfinders. These are designed to fully utilize all the electronic advantages of the 205TCC camera. All TCC components are characterized by a double blue line.

The 205TCC has the most precise metering system ever built into a camera or an exposure meter. In the Zone mode the Hasselblad 205TCC is also the first camera to incorporate Zone system metering. It provides photographers with a precise and simple method for using the zone system, as pioneered by Ansel Adams. The TCC film magazine even has a film contrast dial where the black and white zone photographer can dial the exposure corrections necessary for changing the contrast range on the negative directly into the 205TCC's microprocessor, another Hasselblad exclusive.

The Zone mode is but one out of four different exposure modes. The others are the Auto mode, the Differential mode and the Manual mode - allowing the photographer to match the built-in metering system to his or her personal approach. There is also a Programming mode to program additional functions into the camera. Automatic, dedicated flash can be used together with any of the exposure modes.

The Auto mode, Differential mode and Zone mode are all essentially aperture priority/shutter automation modes. The latter two modes give the possibility of carefully evaluating a subject or scene, giving the photographer full control over the tonal content and values of the image. Thus, the designation TCC in the camera's name. TCC stands for Tone and Contrast Control.

Well proven medium format

The Hasselblad 205TCC is a medium format camera with a choice of photographing in the 6x6cm (21/4 square) or 6x4.5cm format. Film magazines are available for 120 or 220 roll film and 70mm long rolls. A magazine for Polaroid film is also available.

The design of the camera is, of course, modular, but all the TCC components are electronically interlinked with reliable databus contacts. These contacts transmit digital data between the lens, the camera and the magazines making them into a unit totally controlled by the camera's Central Processing Unit.

Reliable digital control

The Hasselblad 205TCC is the only medium format camera with a digital electronic system. This control system makes the 205TCC a completely reliable camera. The camera can take rough treatment and will function under harsh conditions with the same precision that one expects from any Hasselblad camera. The digital signal processing and databus design will allow you to add more specialized system components in the future. The 205TCC camera system can grow without the technical limitations often encountered in less sophisticated electronic and mechanical designs.

Human engineering at its best

Using the camera is easy due to the human engineering and use of an easy-to-see liquid crystal display (LCD) readout in the viewfinder. There is also a comprehensive set of warning signals that appears in the viewfinder making photography with the 205TCC practically foolproof. You are always in control, even when working in the automatic mode. You can overrule the automation anytime and make your own adjustments to fine tune the exposure.

There are many advantages offered by this new camera. It is possible to work in a fully automated way. Everything is powered from a single 6V lithium battery which lasts for many exposures. In cold climates it can be used in an external battery pack. You can even work without a battery using the built-in shutters in CF lenses.

A system for creating the ultimate image

The built-in focal plane shutter gives accurately timed speeds from 16 sec to 1/2000 sec plus B. There are six lenses which transfer all the necessary electronic connections to the camera body and the viewfinder display with only four gold plated contacts. They are the Distagon F 2.8/50 TCC, Planar F 2.8/80 TCC, Planar F 2.0/110 TCC, Sonnar F 2.8/150 TCC, Tele-Tessar F 4/250 TCC and Tele-Tessar F 4-350 TCC. In addition, all C and CF and F lenses from 30mm to 500mm, the Variogon Zoom, the Mutar, and the PC Mutar can also be used. There are also special TCC extension tubes from 16mm to 56mm, but most existing tubes and the bellows are also usable.

Automatic dedicated flash with center-weighted OTF metering is possible with various flash units based on the SCA 300 or 500 systems, or the 4504 unit which has all the necessary electronics for dedicated operation built in so it can be connected directly to the camera.

The Hasselblad 205TCC is beautifully designed. As a working photographer you will appreciate its simplicity of operation utilizing a limited number of control buttons which make use of all the sophisticated functions in the camera. All controls can be operated with one hand and without removing the eye from the finder. All the information that you need to know appears on the viewfinder display. Whether you work with existing light or dedicated flash, the display will warn you if anything in the camera is not set properly to produce the ultimate image. You do not have to worry about technicalities, but can concentrate your efforts on what is important, i.e. making photographs of lasting value.

Manufacturer description #2

Camera design: Medium format single lens reflex camera with built-in TTL spotmeter electronically connected to TCC lenses and TCC magazines. Interchangeable lenses, film magazines, viewfinders and focusing screens.

Shutter: Electronically controlled mechanical focal plane shutter with release solenoid system. Horizontally running textile curtains. Shutter speed range B, 16s - 1/2000s. Fully mechanical C setting for built-in leaf shutter lenses. Flash synchronization from B up to 1/90s.

Lens mount: Hasselblad bayonet mount for TCC, F, CF and C lenses. Contacts for databus communication with the TCC lenses.

Viewfinder: Focusing hood with 4 x magnifier, interchangeable with magnifying hood and prism viewfinders with and without exposure meter. TCC viewfinders only acceptable. Acute-Matte focusing screen interchangeable with other Hasselblad focusing screens. Illuminated flash and warning symbols.

Operation display: LCD display in viewfinder with all relevant exposure and operational data and switch-controlled low light illumination.

Camera winding & film advance: Manual single turn winding crank. Simultaneous shutter cocking and film advance. The crank is interchangeable with the Hasselblad motor winder for up to 1.3 frames/second.

Exposure meter: TTL metering at full aperture with TCC lenses. High sensitivity silicon photocell. Spotmeter area approximately 1% of the image area, angle of view from approximately 1-7 degrees depending on lens focal length. Metering range EV -1 to EV 20 at ISO 100/21 degree and f/2,8. Active time 16 s after release of activating button.

Exposure functions: Aperture priority automatic exposure, automatic flash control and full manual control. Exposure compensation +/-5 EV with 1/4 EV increments. AE-lock.

Operating modes: Automatic Mode, Differential Mode, Zone Mode, Manual Mode and Programming Mode.

Film speed range: ISO 12/12 degrees to ISO 6400/39 degrees, selected with film speed dial on TCC magazines or entered in programming mode.

Flash control: Center weighted TTL/OTF flash exposure meter. Full dedicated flash control with automatic shutter speed reset to 1/90 s at faster speed settings. Inhibited flash triggering in at shutter speed settings faster than 1/90 s with non-dedicated flash units.

Selftimer: Default delay 10 s. Delay programmable in 12 steps from 2 s to 60 s.

Battery: 6V, type PX28, UCAR 537, 4G-13 or equivalent lithium type.

Tripod mount: Quick coupling plate and 1/4" socket thread.

The camera body comes with focusing hood, focusing screen, winding crank, shoulder strap, front and rear protective covers.

***

With the Hasselblad 205TCC in your hand you have a tool with a full range of new features. TCC stands for Tone and Contrast Control, a feature that by itself vastly increases your possibilities to control the entire photographic process far beyond what you could do with the previous models. The camera, however, also permits you to use most of the accessories you already have. And it is still you and not the camera that controls your work!

The meticulously shielded and highly accurate spotmeter provides the metering system with the most precise readings in fast action shots or carefully contemplated artistic creations. For the first time you can select the "zone-mode" and let the processor in the camera adjust the exposure for the planned contrast-compensating development correction. Through the viewfinder display it provides you with information on zones, contrast differences, shutter speeds and aperture settings. And still it is the photographer that controls the image.

The 205TCC has four different modes of operating the metering system, easily selected with the mode selector dial on the control panel. And in addition it also has a programming mode where you can insert e.g. the dynamic range of the film to obtain a warning signal when your exposure values are off limits. With a TCC film magazine attached the camera processor automatically gets the film sensitivity information set on the magazine, but if you are using an ordinary film magazine that is not adapted for the 205TCC you can insert the film speed data yourself into the memory of the system. You can also set the selftimer delay within wide limits.

Your flash pictures are made easier and more accurate with the 205TCC combined with a dedicated flash unit, such as the Hasselblad Proflash4504. The sophisticated metering system in the 205TCC meters the light off the film and controls the flash duration for precise exposures also when the flash is combined with ambient light.

Of course you cannot have all this "for free". It takes a sophisticated and powerful electronic setup to keep track of all this information. The 205TCC is provided with a digital system with active members in lenses and magazines, communicating with the "brain", the central processor, through a data bus. Digital operation and databus communication give an unsurpassed functional reliability.

In spite of all its advanced design the 205TCC is still a part of the Hasselblad System and represents a pacesetting system expansion. With the spotmeter built into the camera body you can change viewfinders and focuing screens and you can also use most of your present accessories, some however with minor limitations in the TCC functions.

You will recognize the TCC system by the double blue lines appearing on the left hand side of the TCC camera body and all the TCC accessories.

From the editor

The weight and dimensions are indicated for the camera body with the Planar F 2,8/80mm TCC lens and film magazine A12 TCC.

Subscribe
Notify of
guest

Copy this code

and paste it here *

0 comments
Inline Feedbacks
View all comments
Table of contents
Clickable
Instruction manual
Clickable
Hasselblad V system cameras
Clickable

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.

Limitation of liability • Privacy policy • Contact • Donate

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, 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.