High-Performance Flattener and Reducer Kit with connecting rings for SD81S, SD103S, and SD115S optical tubes.
The kit consists of the high-performance flattener lens, reducer lens, and connecting rings (Spacer Ring SD81, EX Tube 66) designed for prime focus astrophotography with the SD81S, SD103S, and SD115S optical tubes, extraordinary enhancing the flat-field performance, while reduing the focal length by 0.79x. Enjoy high-level prime focus astrophotography by SD series optical tubes which supply two different focal lengths.
The SD flattener HD improves the flat-field performance toward the edge of the field of view closely maintaining the original focal length of the SD-series optical tubes, fully covering the imaging field of DSLR camera with the full-format sensor at an image circle of 44mm diameter. Using in combination with the supplied Reducer HD, the focal length will be reduced by 0.79x (f/7.7→6.1), while maintaining the image circle in dia. 44mm, largely improving sharpness over the entire imaging field of the DSLR camera with the full-format sensor.
The same anti-reflective AS coating, which is used for our high-end VSD 100 f/3.8 Astrograph, is used to take advantage of 99.9% superb high transmission of light per lens surface. Loss of light, ghost, and flare images are eliminated substantially due to the complete matte finish inside.
The supplied Reducer HD can be used as a reducer for the AX103S and VC200L optical tubes. The AX103S optical tube incorporates a flattener lens and outperforms high imaging capability even by itself. For this reason, the Reducer HD can be used without using the SD Flattener HD. The AX103S covers an imaging field of a DSLR camera with a full-format sensor with a 44mm image circle.
Originally incorporating a flattener lens inside, the VC200L optical tube offers high imaging capability by itself. For this reason, the Reducer HD can be used without using the SD Flattener HD together. The VC200L delivers 36mm image circle (peripheral illumination by 60%) fully covering an imaging field of a DSLR camera with an APS-C sensor, and also offers comparably sharp images with the center in spite of 47% peripheral illumination at dia. 44mm image circle. It covers an imaging field of a DSLR camera with an image circle of dia. 28.8mm with APS-C sensor and dia. 44mm with a full-format sensor.
Full-format and APS-C is a common name for size representing the size of the light-receiving plane (imaging sensor or film) of a DSLR camera. Full-format (36x24mm), APS-C (23x16mm), and Four Thirds (17.3x13mm) are typically available standards for DSLR cameras. In general, the larger the light-receiving plane, the larger the range can be shot.
SD Reducer HD Kit
SD81S
SD103S
SD115S
AX103S
VC200L