Pentax Super-Multi-Coated Takumar 28mm f/3.5 SM Close this window to return to eBay Specifications Super-Multi-Coating Construction Fixed-Focus Mark Infra-red Index

  The 28mm lens is considered to be an wide-angle lens. It is a great lens for shooting in congested areas, for creating or enhancing the depth of a subject.  Once considered ultra-wide, it is now a compulsory component in a well equipped system.  This lens produces images that include the view that we normally recall about a scene even though our actual angle of view is narrower.  Compared to a 50mm "normal" lens with a 46 degree angle of view, this lens nearly doubles the width of the scene captured from the same vantage point.  Straight lines do not appear curved as they would with a "fish-eye" lens. When making a photograph with the camera level the scene will appear very normal but with a great deal of depth. Due to the wide angle coverage that this lens provides, the multi-coating and the special lens hood are indispensable in preventing undesired flare, ghost imaging and reduction in contrast often associated with conventionally coated optics.

Specifications | Super-Multi-Coating | Construction | Fixed-Focus Mark | Infra-red Index

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Features

Super-Multi-Coating

This coating - developed for spacecraft windows and precision optical machines - reduces internal reflections to a low 0.2% per air-to-glass surface. As a result, more light is transmitted to your film. Flare, fog and ghost images are virtually eliminated. Image contrast is greatly improved, even in detail areas. Color balance is also improved since transmission is more even over the visible light spectrum. No conventionally coated lens in the world can match the performance of a Super-Multi-Coated Takumar. Shoot toward the sun or reflective surfaces. Take strongly back-lit photos. Tackle really tough lighting situations. If your lens is a Super-Multi-Coated Takumar, you can expect crisper detail, sharper contrast and more vibrant color.

To understand why this was such a great breakthrough, in lens manufacture, you need to know a few basics. All lens elements have a common problem - reflection at every glass-to-air surface. This means light transmission is lost, and light scattering inside the lens causes flare and ghost images. As recently as 1940, no coating was used on photographic lenses, and less than half the light entering was transmitted through the lens. Over the years (Asahi was among the first) developed methods of depositing a thin film of magnesium fluoride on lens surfaces. This was followed by 2 or 3-layer coatings which further reduced reflections. With the advent of the space age, researchers started work on ways to cut reflection on instrument cover glasses for high performance aircraft and for viewing windows in Mercury, Gemini, Apollo, and LEM spacecraft. This research was the basis of the multi-coating system used exclusively on the Super-Multi-Coated Takumar lenses that cuts surface reflection to a phenomenal low of 0.2%. Ghost images are eliminated or drastically reduced, even when shooting into the sun. Reduced flare means greater contrast, much truer color, much more detail in both highlight and shadow areas. Specifications | Super-Multi-Coating | Construction | Fixed-Focus Mark | Infra-red Index Close this window to return to eBay Click or the [ BACK ] button on your browser to return to the previous page.

Construction

	Asahi Optical began manufacturing specialized lenses in 1919, and has been producing lenses for general photography since 1932, twenty years before the Pentax, the first SLR camera from Japan - was manufactured. Painstaking hand craftsmanship, the highest quality raw materials and the most advanced technological know-how are combined in the manufacture of each Super-Multi-Coated Takumar. In the beginning, lens design required logarithmic tables, slide rules- and great patience. It often took three competent designers several years of steady work to complete the computation of a single 4-element lens. Today, Asahi utilizes the most modern electronic computer equipment which performs extremely complicated calculations very rapidly and with great accuracy.
Fine optics alone cannot make a superior lens; the mechanical components are equally important. Lens barrels of Super-Multi-Coated Takumar lenses are precision machined for accurate positioning of all elements. Tolerances are so tight you have to break a vacuum to disassemble some elements. Each Super-Multi-Coated Takumar has dust and moisture-proof seals and a special diaphragm damper that cuts down on wear, vibration and bounce so you get consistent aperture openings. All mechanical components are precision machined to microscopic tolerances. Specially lubricated, wear-resistant metals assure consistently accurate apertures year after year. Screw mounts are the most precise method of holding a lens firmly in place. Perfectly matched threaded mountings on Super-Multi-Coated Takumars make changing lenses quick and easy - even in the dark.
Specifications | Super-Multi-Coating | Construction | Fixed-Focus Mark | Infra-red Index Close this window to return to eBay Click or the [ BACK ] button on your browser to return to the previous page.

 

Fixed Focus Mark

Since wide-angle lenses have a great depth of field, they are suited for snapshots. To obtain maximum depth of field, convenient marks have been included on the Takumar wide-angle lenses. They are shown in red figures on the diaphram and distance scales. If you set these figures to the index, you do not have to turn the focusing ring every time you want to take a snapshot. The photo at the left indicates that the lens diaphram is set to F8 and the distance scale is set at 3 meters, both figures being the fixed-focus marks. read the depth-of-field guide, and you will see that this setting affords a depth of field from 1.3 meters to infinity; within this field everything will be in focus. However, even without using the fixed focus mark, it is possible to make extremely efficient judgements about depth of field by checking it on the scale which shows the relation between distance setting and aperture.

Specifications | Super-Multi-Coating | Construction | Fixed-Focus Mark | Infra-red Index Close this window to return to eBay Click or the [ BACK ] button on your browser to return to the previous page.

Infra-Red Index

When taking infra-red photographs, the focal point shifts slightly, and therefore, the lens must be extended accordingly. The difference varies depending on the lens, and it is indicated by the small "R" index or short orange line. In infra-red photography, use this infra-red index. First, focus your lens on your subject. Determine the lens-to-subject distance from the distance scale. Then match your "R" mark by turning the distance scale accordingly. Like the photo at left, if your subject is in focus at infinity, turn the distance ring and move infinity mark to the "R" index. Also, remember to use an R2 (red) or O2 (orange) filter and special infra-red film in this special photography.

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