Advanced technology in designing the ultimate lenses

  1. For bright, clear images
  2. For clear, natural image rendition
  3. For comfortable, flawless operation
  4. For greater reliability

For bright, clear images

Aero Bright Coating II / Aero Bright Coating

Aero Bright Coating is a new layer formation process based on nanotechnology. It applies a silica aerogel coating layer with a uniform porous structure over a regular multi-layer coating. By trapping low-refraction air between stablesilica nanoparticles, it forms a super-low refraction, high-transparency coating. It also drastically reduces surface reflections, while minimizing flare andghost images. With Aero Bright Coating II, by increasing the amount of air trapped in the silica aerogel layer, this process successfully form a super-low reflaction coating superior to that of the original Aero Bright Coating. By considering the lens characteristics, selected coating is adopted to achieve optimum performance.

HD Coating

The manufacturing process for traditional vacuum deposition coating posed problems. Uneven membrane thickness and variations in the refractive index tend to occur due to difficulties in enhancing membrane density. To solve this, HD coating is created via a specialized method to achieve a high-density membrane with nanometer precision. This method reduces reflectance across the entire visible spectrum. It also produces a very hard and durable coating.

Multi-layer coating, Ghostless Coating and internal reflection prevention

PENTAX interchangeable lenses are treated with an original multi-layer coating to reduce the surface reflection to approximately 1/10 of single-layer coatings. This coating increases the transmissivity of light over the entire visible light range, while almost completely eliminating harmful UV light. It also reduces flare and ghost images under adverse lighting conditions such as backlight to deliver sharp, high-quality images. Some lenses are also treated with the PENTAX-exclusive Ghostless Coating, which reduces reflections from specific types of light and minimizes the generation of ghost images. PENTAX selects the best possible coating for each lens by carefully assessing key factors such as the configuration of the lens and the characteristics of the glass. PENTAX also applies a combination of flocking and painting processes to the interior of lens barrels to prevent internal reflections, while incorporating a light shielding mechanism to one optical element in each lens group to prevent scattering of light. All these features work collectively to minimize flare and ghost images.

For clear, natural image rendition

AL (Aspherical Lens) elements

Optical lenses are affected by various types of aberrations, which prevent them from delivering ideal imaging performance. One of these is spherical aberration, in which light rays fail to converge on a single focal point, resulting in blurring of the point image. AL (Aspherical Lens) elements can be used to minimize this aberration, as well as to reduce the number of component elements needed, allowing for the design of a compact, high-performance lens. In addition to glass-molded AL elements, PENTAX has also developed hybrid AL elements by laying special transparent resin over optical glass, as well as resin-molded AL elements. PENTAX selects the best AL element for each lens, based on factors such as the configuration, aperture size and application.

Special optical glass elements

The refraction rate of glass varies depending on the wavelength of light. Because of this, natural light may fail to converge on a single focal point because it contains light of varying wavelengths. For instance, when an image is enlarged on a computer screen, you may notice purple blurring around red dots. This is called chromatic aberration. With conventional lenses using optical glass elements, it becomes increasingly difficult to correct this aberration as the focal length becomes longer. To minimize chromatic aberration, PENTAX makes use of three different types of glass with low light spectral dispersion in its optical elements: ED glass, Anomalous Dispersion glass and high refractive index low dispersion glass. By selecting the most appropriate glass types for a specific lens, PENTAX assures optimum imaging performance for every single lens, from wide-angle to telephoto.

Large, exclusively designed hood

PENTAX interchangeable lenses are equipped with a host of innovative features, such as original multi-layer coatings and devices used to prevent reflections inside the lens barrel. The large, exclusively designed hood comes in handy in eliminating flare and ghost images when shooting under difficult lighting conditions, such as backlight. The hood is either included or built into most PENTAX lenses to provide the maximum light shielding effect.

Electromagnetic Diaphragm Control Mechanism (available with KAF4-mount lenses)*

This mechanism digitally controls the aperture blades to assure high-precision exposure control. Unlike mechanical control systems, in which the blades are driven using force supplied by the camera body with lever action, this electromagnetic mechanism incorporates the aperture blades and the driving motor as a unit in the lens barrel. Aperture settings are changed using the electric power and digital signals supplied by the camera body. This assures extremely accurate diaphragm control, with minimal operational noise and vibration. The aperture blades are also smoothly and flawlessly driven. Even when the lighting level fluctuates during video recording, the mechanism instantly shifts the aperture blades into the correct position to avoid unexpected changes in exposure level and prevent annoying diaphragm-driving sound from being recorded, making it possible to record natural, flawless video clips.

  • * For shooting with a KAF4-mount lens featuring the Electromagnetic Diaphragm Control system, the camera’s firmware must be updated to the latest version. Use of the latest firmware is strongly recommended.
    Cameras compatible with KAF4-mount lenses: K-1 Mark II, K-1, KP, K-3II, K-3, K-S2, K-S1, K-70 and K-50. If an incompatible camera is used, the diaphragm control mechanism is locked, causing inaccurate exposure control.

Electromagnetic Diaphragm Control Unit

Round Diaphragm

Lenses with polygonal irises tend to suffer a streaking light effect caused by refraction when shooting point light sources. PENTAX’s Round Diaphragm, however, produces an image in which point light sources appear to be enveloped in gentle, circular light. Even with ordinary subjects, the round iris produces a natural bokeh effect in the background, and captures the highlights as beautifully blurred, perfectly round light spots.

Round Iris Diaphragm

smc PENTAX-DA55mmF1.4 SDM

Comfortable Operability

PLM, SDM, DC = Internal Lens Motor AF

Some lenses include PLM (pulse motor), SDM (supersonic direct-drive motor) and DC (direct current motor) in their lens names. These lenses perform the AF operation using the motor drive in the lens barrel. This enables a quieter and smoother AF operation than body AF operation driven by the focusing mechanism motor inside the camera body, and enables an easy, comfortable focusing operation. Lenses that employ the PLM pulse motor, the lead screw directly leads the drive mechanism which are not only silent, but also offer high-speed, high-precision AF operation. The SDM supersonic motor includes a brake mechanism for allowing high-accuracy speed control and position control.

IF (Inner Focus) system

Conventional interchangeable lenses employ an all-group shifting system, in which all elements of the optics shift during focusing. The IF system, however, shifts only part of the optics during focusing. Since this can reduce the lens’s overall weight — which the motor has to drive during autofocus operation — it not only assures faster AF speed, but also shortens the minimum focusing distance to improve imaging performance in close-up photography. It also eliminates the change in the lens length, maintaining the ideal weight balance regardless of subject or shooting distance — a great advantage, especially with super-telephoto lenses.

smc PENTAX-DA200mmF2.8ED[IF] SDM

Multi-group zooming system

In most zoom lenses, one lens group shifts to change the focal length while another shifts to correct focus, because accurate focus has to be maintained on the subject even after the focal length has changed. It means that two lens groups are shifted simultaneously. Unlike these lenses, most PENTAX zoom lenses feature a more sophisticated multi-group system, in which three to five lens groups are shifted all at once to improve imaging performance and operability over the entire zoom range, assure a higher magnification, and reduce body size. They also feature an array of other advanced technologies, including an inner zoom mechanism that shifts only the inner lens groups to keep the total lens length unchanged, and a nonlinear movement zoom mechanism in which each lens group performs complex movements.

smc PENTAX-DA60-250mmF4ED[IF] SDM

Quick-Shift Focus system

This user-friendly system lets you effortlessly change the focus mode from autofocus to manual without any switching action. Simply by turning the focus ring during AF operation, it instantly switches to manual-focus mode to allow for extra-fine focus adjustment — a feature that is extremely useful in close-up photography. To further improve the system’s operability and versatility, PENTAX has equipped some lenses with a new triple-mode system: the QFS/A (Autofocus-priority) mode allows manual focus adjustment after the AF operation is completed; the QFS/M (Manual-priority) mode lets you shift the in-focus point even when the AF system is still in action; and the MF (Manual Focus) mode lets you instantly switch to manual focusing with a single twist of the lens’s focus ring.


Focus range limiter

This function lets you regulate the focus range to shorten the time required for autofocus operation.


Operation window for circular polarizing filter

To facilitate the use of a circular polarizing filter, most PENTAX lenses are designed with a non-rotating front end, which remains stationary during zooming and focusing operation. In addition, large lens hoods feature an operation window at their bottom to assure easy control of a circular polarizing filter without the need to remove the hood from the lens.

Initial closed position

PL filter control position


For greater reliability

Dustproof, weather-resistant construction

PENTAX faced a series of demanding tasks to perfect these structures. Some lenses required a special structure with an air vent because of their extended lengths, while others demanded more effortless, flawless operation. Each challenge was overcome. PENTAX plans to make these dependable structures a standard feature of not only high-grade lenses but also all interchangeable lenses in the future.

smc PENTAX-DA55mmF1.4 SDM

HD PENTAX-DA 20-40mmF2.8-4ED Limited DC WR

SP(Super Protect)Coating

This PENTAX-exclusive coating provides outstanding repellent performance against water and grease. Applied to the front surface of the first lens element, it not only protects the lens from dust, water and grease, but also makes it easier to wipe these substances off the lens surface. It is also highly resistant to abrasion and scratch, helping to keep the lens in prime condition. Applied to many PENTAX lenses, this coating has proven to be extremely effective in protecting the lens surface.

Comparison of dirt adhesion (oil-based ink)

A lens surface treated with SP Coating has a very smooth surface without the adhesion of the oil-based ink.

Comparison of wipe-off (oil-based ink)

A lens surface treated with SP Coating can be wiped clean more easily and completely, even after the ink has dried.

PENTAX K mount

Every lens mount designed for PENTAX interchangeable lenses since 1975 has been based on the bayonet-type K mount. This PENTAX-exclusive mount harmonizes a large aperture with ease of lens change, high precision and exceptional durability. These outstanding features make it easy to incorporate advanced diaphragm control and autofocus mechanisms into a new lens, while retaining full compatibility with existing lenses. Despite differences in their performance and function, PENTAX designs both cameras and lenses to ensure utmost versatility.

Uniform color balance

All PENTAX interchangeable lenses provide a uniform color balance and deliver the identical, vibrant color tones, even when one lens is replaced with another. Since the days of film-format cameras, this principle has held true because PENTAX wants always to deliver beautiful, high-quality images with its lenses, whether old or new.

Quality Control

All PENTAX interchangeable lenses are subjected to the stringent inspections throughout their production process — from design to manufacturing. After their production, they are measured for such specifications as resolving power, contrast, color and aberrations using PENTAX-developed measuring instruments, and objectively evaluated for their numerical values. The lenses which have failed to meet PENTAX’s strict quality standards are sent back for fine-tuning. Thanks to this dependable quality-control system, every PENTAX lens delivers the optimum quality and performance to our users.