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The 50mm F1.4 EX DG HSM is the latest design from independent lens maker Sigma, announced in March 2008. It's a rare example of what is rapidly becoming an endangered species; an all-new, large maximum aperture, fixed focal length 'prime' lens, and (like Sigma's 30mm F1.4 DC before it) a hugely welcome addition to a market in danger of becoming saturated by identikit slow zooms. The 50mm focal length makes it a classic 'standard' lens for 35mm full-frame cameras, while on DSLRs with smaller format sensors it acts as a short 'portrait' telephoto, with an equivalent angle of view ranging from 75mm (on 1.5x 'DX' format) to 100mm (on Four Thirds DLSRs). The fast maximum aperture offers several key advantages over zooms, including the ability to isolate a subject by selectively blurring the background, the option to shoot in low light whilst maintaining reasonably high shutter speeds (ideal for indoor photography without flash), and the provision of a bright viewfinder image for composition
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Sigma has said that its 18-250mm F3.6-6.3 DC OS HSM superzoom lens is now available in mounts for Sony and Pentax SLRs. This lens incorporates a Hybrid Optical Stabilisation system, which can be used on bodies which have built-in anti-shake (the camera's stabiliser must however be switched off). It also has a hypersonic motor for fast and quiet autofocus, and a minimum focus distance of 45cm for close-up photography. The MSRP is $800 in the USA, and £559.99 in the UK
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Download This SRP is submitted in partial fulfillment of the requirements of the Master of Strategic Studies Degree. The U.S. Army War College is accredited by the Commission on Higher Education of the Middle States Association of Colleges and Schools, 3624 Market Street, Philadelphia, PA 19104, (215) 662-5606. The Commission on Higher Education is an institutional accrediting agency recognized by the U.S. Secretary of Education and the Council for Higher Education Accreditation. The views expressed in this student academic research paper are those of the author and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.
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Download half-frame DSLRs (often referred to as ‘APS-C’ size) are great for photographers who want to use long lenses. The small sensor in effect multiplies the focal length by a factor of around 1.5x without any loss in f-stop. The problem is that the focal length of wide-angle lenses are also multiplied by the same factor. So your expensive absolute wow of an ultra-wide 15mm lens now only looks as though it is a much less impressive 24mm. It’s been a definite case of ‘hello DSLR, good bye ultra-wides’. Until now, that is, for new ultra- short focal length zooms have recently been designed to produce superb results with DSLRs having half- frame sensors. One such lens is the 10–20mm f/4–5.6 from Sigma, which makes images equivalent to a 15–30mm on a full-frame camera. At its widest, that’s over 100 degrees angle-of-view
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Download ioften get requests for lens recommen- dations from friends, though it is of course the favourites, the 12-24, 17-70 - the mid-range zooms -that get all the atten- tion. When moving to a DSLR from a high- er-end bridge camera though, there can be a bit of a culture shock. Weighing 1.8kg and 220mm long, the Sigma 50-500mm lens is far from being the kind of small light zoom you might buy as part of a routine kit, but nonetheless it shapes up to be an incredibly good compromise – it is amongst the smaller lenses in this focal range. Its advanced optical design is opti- mised for DSLRs cameras, using four ele- ments of SLD (special low dispersion) glass for excellent correction of colour aberration throughout the zoom range, while reducing flare and ghosting
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