Click on each question to link down to the answers.
1. Are Sigma lenses compatible with my new camera?
2. I’ve recently seen a reference to FLD glass being used in Sigma lenses, is this different from ELD and SLD glass?
3. Some Sigma lenses are designated "DG". What does this mean?
4. Does Sigma offer any teleconverters?
5. Where are Sigma lenses made?
6. What are APO lenses?
7. What are Aspherical lenses?
8. What are Macro lenses?
9. Does Sigma make lenses for manual focus cameras ?
10. What does HSM stand for and what is it?
Answers
1. Are Sigma lenses compatible with my new camera?
Please refer to our compatability chart: http://www.sigmaphoto.com/sigma-lens-chart Please contact Sigma Corporation of America at 1-800-896-6858 or via email info@sigmaphoto.com
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2. I’ve recently seen a reference to FLD glass being used in Sigma lenses, is this different from ELD and SLD glass?
FLD ("F" Low Dispersion) glass is the highest level low dispersion glass available with extremely high light transmission. This glass has a performance equal to flourite glass which has a low refractive index and low dispersion compared to current optical glass. FLD glass offers superior optical performance, equal to flourite, at an affordable price.
ELD (Extraordinary Low Dispersion) glass has lower dispersion characteristics than SLD (Special Low Dispersion) glass, which Sigma has been using in its APO lenses (and some non-APO lenses as well) for many years now. It has other advantageous properties as well.
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3. Some Sigma lenses are designated "DG". What does this mean?
The DG designation applied to most newer Sigma lenses indicates that the lens is especially suited for use with digital SLR cameras. The DG lenses feature improved (more even) light distribution from image center to edge, and incorporate the latest multi-layer lens coatings to avoid reflections of the sensors of digital cameras. This is important in digital photography, but is also useful in 35mm photography, especially when slide film is used. Lenses designated as DC are designed exclusively for use with digital cameras having APS-C size image sensors. They feature smaller image circles and often feature shorter focal lengths (e.g. 10-20mm DC, 17-70mm DC, 18-50mm DC, 18-200mm DC, etc.). The shorter focal lengths are desirable, because most digital SLR cameras have image sensors whose dimensions are considerably smaller than a 35mm negative (usually by a factor of 1.3X to 2.0X), making the lens’ angle of view equivalent to that of a longer lens on a 35mm cameras.
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4. Does Sigma offer any teleconverters?
Sigma offers both a 1.4X and a 2.0X autofocus APO teleconverter. These are dedicated teleconverters, designed for use with certain compatible lenses. Please refer to our teleconverter compatability chart: http://www.sigmaphoto.com/sigma-lens-teleconverter-compatability-chart
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5. Where are Sigma lenses made?
All Sigma products, lenses, cameras and flash units are manufactured exclusively by Sigma in Sigma’s own factory in Aizu, Japan. No Sigma Corporation product - lens, camera or flash - is manufactured outside of Japan. This is very unusual these days, as most companies have at least some of their products produced outside of Japan because of cost considerations.
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6. What are APO lenses?
Apochromatic lenses are telephoto and telezoom type lenses which use special optical designs and optical materials (SLD or ELD glass) to improve their performance. The result is images which have greater contrast, sharpness and color definition than a comparable non-APO type lens . All Sigma apochromatic lenses are identified by the APO designation in their descriptions. Please see the Lens Chart for this and other specific lens information.
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7. What are Aspherical lenses?
Many Sigma lenses make effective use of Aspherical lens elements. This technology allows one Aspherical lens element to perform the functions of two or more conventional spherical elements, thus allowing the lens to be made more compact and lightweight, while retaining high levels of performance. In the 20mm f/1.8, 24mm f/1.8, 28mm f/1.8 EX DG lenses, for example, these Aspherical elements eliminate the sagittal coma flare that accompanies large lens diameters. They effectively suppress the flare. In zoom lenses, where the wide angle range is extended - such as the 15-30 f/3.5-4.5 EX DG - distortion control can be enhanced by the use of Aspherical elements.
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8. What are Macro lenses?
Macro lenses are those which can focus unusually close, providing large reproduction ratios (e.g. 1:3, 1:2, 1:1, etc.) Sigma offers more lenses with macro capabilities than any other lens or camera maker. The choice of which lens to use depends on the application.
The shorter lenses, 50mm and 105mm provide greater magnification (reproduction ratio) capabilities (1:1 without accessory), and shorter working distances. These are desirable for photographing inanimate or slow moving subjects or for copy work. The 105mm f/2.8 EX Macro lens can also be useful for portraiture.
Longer Macro lenses like the 180mm f3.5 EX APO Macro can allow even greater working distance while still providing up to 1:1 reproduction. Greater working distances are useful when photographing animate subjects which may become evasive or aggressive if approached closely by a photographer.
Sigma offers several zoom lenses (e.g. 70-300mm F4-5.6 DG Macro) which combine reproduction ratios up to 1:2 with the convenience and versatility of a zoom lens. These can be invaluable for general photography including extreme close-ups, while carrying only one lens around.
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9. Does Sigma make lenses for manual focus cameras ?
Sigma no longer manufactures lenses for most manual focus camera. However, in some cases (e.g. Nikon and Pentax) AF type lenses can be used for manual focus on the manual focus cameras.
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10. What does HSM stand for and what is it?
HSM stands for Hyper Sonic Motor. It is a new type of motor used in some of Sigma’s newer lenses. The technology employed is similar to that used in certain lenses made by other camera manufacturers. The benefits of HSM system are: virtually silent autofocus function, very quick responsive autofocus function. Sigma is the only independent lens maker offering lenses with this technology. We have a number of HSM type lenses for Canon and Sigma AF cameras, and we also have several HSM lenses for Nikon AF cameras (N55, N65, N70, N75, N80, N90, N90S, F100, F4s, F5, D1, D1X, D1H, D100 and D70, as well).
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