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High peformance flattener and reducer kit. 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 reducing the focal length by 0.79x.
Ultra sharp image over entire imaging field on DSLR full-format sensor. The SD flattener HD improves the flat-field performance toward the edge of field of view closely maintaining the original focal length of the SD-series optical tubes, fully covering the imaging field of DSLR camera with full-format sensor at 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 becomes F/6.1), while maintaining image circle in dia. 44mm, largely improving sharpness over the entire imaging field of the DSLR camera with full-format sensor.