More than 180 years have passed since Frenchman Niépce took the world’s first photograph.
Through the lens, we have encountered a truly wide range of emotions.
In the digital age, this emotion has further grown in range and depth for even greater richness of expression.
As an optical manufacturer, PENTAX strives to anticipate the trends for the age in our constant pursuit of the highest possible image quality.
It is our firm belief that the starting point of photographic expression is in the lens, and so we have devoted ourselves to developing a lineup of the most advanced lenses possible.
To deliver the ideal digital image, lenses must provide not only high performance measured by numerical standards, but also creative power and lens effects that can affect human emotions.
At PENTAX, we are delivering the joy of photographic expression to people all over the world.
The PENTAX digital SLR K series cameras have a built-in Shake Reduction (SR) mechanism in the camera body. This enables great freedom in the design without being constricted by the optical system or mechanisms that correct for hand shaking. The lens can be made into a compact design, and even better rendering performance can be achieved. Shake Reduction is also extremely advantageous for large, older type PENTAX lenses.
PENTAX Advanced Lens Technology Bringing You Closer to the Ideal Lens.
Aero Bright Coating is PENTAX's newest lens coating developed from nanotechnology. It uses a silica aerogel coating layer with uniform porous structure applied over a regular multicoating. This traps low-refraction air between stable silica nanoparticles for enabling a coating with super-low refraction rate and high transparency. The coating has greatly reduced surface reflection. In addition, using a new super-low refractive index layer formation process, we have developed Aero Bright Coating II, which enhances low-reflectance properties.
PENTAX interchangeable lenses use our unique multicoating for reducing the surface reflections to approximately 1/10 of single-layer film coatings. This coating increases the transmissivity of light over the entire visible light range and also nearly completely cuts out harmful UV light. This coating also reduces ghosting and flare under backlighting and other adverse conditions for providing images with a high sense of transparency.
Moreover, some lenses use PENTAX's exclusive ghostless coating for reducing reflections from specific types of light for minimizing the occurrence of ghosting. PENTAX performs the optimum control of each coating for each lens to match the lens configuration, glass characteristics, and other factors. Also, flocking and paint are combined for preventing reflections inside the lens barrel. A light shielding mechanism is installed to prevent scattering of light from a lens within the lens group together with other measures for minimizing ghosting and flare.
Ghosting due to backlighting
Photography with a ghostless lens
Typically, multicoatings are formed by using vacuum deposition to apply a thin layer to the lens surface. However, this fabrication process also presents problems because of the difficulty in increasing the density of the coating film and the variation in refraction rates and film thicknesses. PENTAX's solution to these problems was our HD Coating, which is fabricated using PENTAX's exclusive special fabrication process, where high-density film is applied with high precision at the nanometer level. This enables the reliable formation of the designed film thickness for a dramatic reduction of the reflection rate (up to 50% compared to conventional coatings) over the entire visible light range. It is also effective in reducing ghosting and flare. Moreover, the film coating has an extremely high hardness for providing superior durability.
lthough PENTAX interchangeable lenses include a host of features such as our unique multicoating and prevention of reflections inside the lens barrel, a large specialized hood is either included or built into most PENTAX lenses for minimizing ghosting and flare that occurs during backlighting and other adverse conditions. A large hood size is used for maximum effectiveness, where standard and telephoto lenses use a round-shaped hood with depth, and wide-angle lenses use a flower-shaped hood with cutouts.
Various types of aberration can occur in optical lenses that hinder the achieving of the ideal imaging performance. One type is spherical aberration where the light rays do not converge in a single focal point, resulting in blurring of the point image. Aspherical lenses (AL) can be used to minimize this aberration and reduce the number of component lenses for enabling a compact, high-performance lens design. In addition to glass-molded aspherical lenses, PENTAX has developed hybrid aspherical lenses, where special transparent resin is affixed to optical glass, and resin molded aspherical lenses. The optimal aspherical lens is selected based on the lens configuration, aperture size, application, and other factors.
The refraction rate of glass varies depending on the light wavelength. For this reason, because natural light consists of light of various wavelengths, this light fails to converge to a single focal point when passing through a lens. When an image is enlarged on a computer screen, you can sometimes see purple blurring around images of red points, for example. This is called chromatic aberration. In typical lenses using optical glass, this is difficult to correct as the focal length becomes longer. To minimize the chromatic aberration, PENTAX uses ED (Extra-low Dispersion) Glass, Anomalous Dispersion Glass, and high-refraction low dispersion glass, all of which have low spectral dispersion of light beams. The appropriate glass types are used for attaining exceptional imaging performance in both telephoto lenses and wide-angle lenses.
In typical lenses, the aberration correction is balanced based on frequently-used shooting
distances, but this can result in aberration at other shooting distances. To resolve this
problem, PENTAX uses a floating lens system for changing the space between parts of the
lens system based on the shooting distance. In typical lenses, this improves the imaging
performance for closeup photography and also enables shorter minimum shooting distances. For large-aperture, wide-angle lenses in particular, this corrects the field curvature which tends to occur at close ranges for providing sharp delineation from near to far distances. Also, in macro lenses which are primarily intended for closeup photography, this enables improved imaging performance at close distances. This floating system is also incorporated into the inner focus of the lens.
FREE is an abbreviation for Fixed Rear Element Extension. It is a type of floating lens system where the front group only of the lens system is moved without moving the rear group during the focusing operation. Changes in performance based on the shooting distance, which tends to occur at an open F value, are reduced, and this enables sharp delineation performance from near to far distances.
In lenses where the iris has a polygonal shape when opened, refraction can cause streaks of light to occur when shooting point light sources. With round iris diaphragms, on the other hand, the light sources appear to be enveloped in soft, rounded light when they are captured. Even in regular photography, blurred light particles appear soft and natural without a polygonal shape.
Round Iris Diaphragm
smc PENTAX-DA★55mmF1.4 SDM
This mechanism performs diaphragm control operations by receiving electronic signals from the camera body and shifting the aperture blades with the driving motor built into the lens. It lets the user change aperture settings more flexibly during movie recording, because it operates very quietly by minimizing the diaphragm control noise that otherwise could be recorded in movie clips. It also controls aperture more accurately to assure stable, high-precision exposure control, especially when an AF rear converter is used for shooting.*
*The HD PENTAX-DA 55-300mmED PLM WR RE lens does not accept the rear converters A1.4X-S and A2X-S.
Electromagnetic Diaphragm Unit
Some lenses include SDM (supersonic direct-drive motor), DC (direct current motor) and PLM (pulse 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. The SDM supersonic motor includes a brake mechanism for allowing high-accuracy speed control and position control. Lenses that employ a drive mechanism which directly links the PLM and lead screw are not only silent, but offer high-speed, high-precision AF operation.
Typical interchangeable lenses use an all-group shifting system where the entire lens group moves to focus. By contrast, an IF system moves only a portion of the lens system to focus. In the IF system, the lenses driven by the motor during the AF operation are lighter for faster AF operation and shorter minimum shooting distance, which enables improved imaging performance during closeup shooting. Also, the total lens length does not change due to the focusing operation for preventing weight imbalances, which is particularly advantageous for super telephoto lenses.
In zoom lenses where the focal length is controlled while holding an accurate focus, one lens system moves to change the focal length while at the same time, another lens system must correct the focus. For this reason, at least two lens groups must be moved in a zoom lens. To enable improved performance over the entire zoom range, higher magnification, and a more compact and easy-to-use design, most PENTAX zoom lenses use three to five moving lens groups instead of only two. These lenses incorporate PENTAX's advanced technology features such as our inner zoom which moves only the internal lens system without changing the total lens length and nonlinear movement zoom where each lens system performs complex movements.
After focusing using the autofocus, the focus ring can be turned to allow immediate
focus adjustment using the manual focus. This feature enables smooth operability
by eliminating the need for an AF/MF switching operation. This is useful during
closeup photography, for instance, when you want to shoot while making fine
adjustments to the focus. Some lenses have the ability to switch between AF priority mode (MF operates after completion of autofocusing) and MF priority mode (MF operates even during autofocusing).
By limiting the focus range, it is possible to shorten AF time.
This mode remembers the focus position so you can return to that position when necessary. This helps you avoid missed shutter opportunities when the distance to the subjects changes, such as when shooting sports scenes.
Most PENTAX lenses are designed so that the lens tip does not rotate when zooming and focusing to enable easy usage with circular polarizing filters. In addition, the large hoods include a window in the bottom section so that you can operate the circular polarizing filter while the lens is still under the hood.
PENTAX's SLR cameras are resistant to the adverse conditions of outdoor photography and can be used even under severe environmental conditions. To enable use with these cameras, the paired lenses must also have exceptional dust-resistant and weather-resistant performance. For this reason, PENTAX has developed dust-resistant and weather-resistant lenses that have been sealed for preventing the entry of water and dust. Some lenses also have an enhanced weather-resistant construction that can protect against the splashing of rainwater. We plan to overcome issues such as lens structures that require air removal due to the lens length or lens operation comfort for providing not only high-performance lenses, but lenses that can be used for a wider range of applications by enhancing the basic specifications of PENTAX interchangeable lenses.
SP coating is a PENTAX-original special coating that provides superior performance in repelling water and oils. It is used on the front surface of the first high-performance lens for effective protection of the lens surface. This coating not only prevents adhesion of dust, water drops, oils, and other substances, but it also makes it easy to wipe off objects that adhere to the lens.
The lens mounts for PENTAX interchangeable lenses are based on the bayonet K mount, which has remained unchanged since its inception in 1975. It is a mount unique to PENTAX that features a large aperture combined with superior ease of replacement, accuracy, and toughness. These features are utilized to comfortably incorporate an iris control mechanism, autofocus mechanism, and other functions for enabling nearly complete compatibility with conventional lenses. The PENTAX K Mount keeps its advanced versatility despite differences in camera and lens functions.
All PENTAX interchangeable lenses have a uniform color balance for delivering the same vibrant color tones even when the lenses are replaced. This remains unchanged since the era of film cameras. This enables you to shoot the stunning images in the same way, whether using your favorite old lens or a new lens.
PENTAX interchangeable lenses undergo a strict quality control process from the design stage all the way to the manufacturing stage. All completed lenses are measured for their resolution, contrast, color tone, various aberrations, and a variety of other parameters using measuring instruments developed exclusively by PENTAX for conducting an objective numerical evaluation. The lenses that fail to meet our strict quality control standards are readjusted or modified as a part of our effort to maintain the highest quality in our products.