Pre-PMA 2005: Sigma today announced that they will be releasing DG ('digitally optimized') versions of ten of their telephoto lenses (six zooms, four primes). DG lenses provide full compatibility with film and digital SLR's but have been 'optimized' (there's no detail on exactly what this means) for use with digital SLR's.

Press Release:

DG version of ten telephoto lenses is available

Sigma Corporation is pleased to announce the launch of the ten DG EX telephoto lenses. Recently, the demand for digitally optimized lenses increases rapidly as digital single lens reflex camera increases its market share. Sigma Corporation has started production of wide-angle lens DG series in 2000 and the number of DG series reached to thirteen models as of February 14, 2005. This time ten new EX telephoto lenses including three single focus telephoto lenses (APO 300mm F2.8 EX, APO 500mm F4.5 EX APO 800mm F5.6 EX) will be introduced to market as DG lens series, which demonstrates high performance with digital single, lens reflex cameras.

APO 50-500mm F4-6.3 EX DG
This lens ensures a superior level of precision from 50mm standard to 500mm ultra telephoto focal length range. Four elements of Special Low Dispersion (SLD) glass effectively compensate for chromatic aberrations. High optical performance is demonstrated throughout the entire zoom range.

APO 70-200 mm F2.8 EX DG
This telephoto zoom lens has a large maximum aperture of F2.8 that is constant throughout the zoom range. To ensure high quality images at all zoom settings, like a fixed focal length lens, it uses four two pieces of Special Low Dispersion (SLD) glass.

APO 80-400mm F4.5-5.6 EX DG OS
Using Sigma's original OS (Optical Stabilizer) function, two types of sensors inside the lens detect vertical and horizontal movement of the camera. By moving a portion of the optical system to compensate for movement, this function delivers outstanding results in compensating for shaking of the camera.

APO 100-300mm F4 EX DG
This telephoto zoom lens provides a large F4 aperture at all focal lengths. With minimal light-fall-off, superior peripheral brightness is ensured. It’s the ideal lens for digital SLR cameras.

APO 120-300mm F2.8 EX DG
This lens offers F2.8 even at 300mm zoom setting and allows you to determine the picture composition you want without having to change your vantage point.

APO 300-800mm F5.6 EX DG
This lens covers the telephoto range from 300mm to the ultra-telephoto range up to 800mm. By continuously varying the angle of view from 8.2º to 3.1º, the lens takes a lot of the footwork out of picture composition.

APO 180mm F3.5 EX DG
Floating Inner Focus system moves two lens groups within the lens, so the lens' physical length remains unchanged. This technique also maintains good correction for Spherical Aberration and Astigmatism, and provides extremely high optical performance from infinity to 1:1 Macro.

APO 300mm F2.8 EX DG
This lens incorporates two Extraordinary Low Dispersion glass elements to produce sharp and high contrast images. A drop in filter holder can be inserted near the rear of the lens, and circular polarizing filters can be used.

APO 500mm F4.5 EX DG
ELD glass maintains high resolution throughout the shooting range, and at all aperture settings. It employs drop –in filter that can be inserted near the rear of the lens, and circular polarizing filters can be used.

APO 800mm F5.6 EX DG
This lens utilizes ELD glass to ensure high contrast at all aperture settings for high image quality. A drop-in type filter can be inserted near the rear, and circular polarizing filters can be used.