SD Reducer HD Kit (Art. #37245)

■ 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 (F7.7→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.

<SPECIFICATION>

"SD Flattener HD"

Optical Tube	SD81S / SD103S / SD115S
Focal Length	625mm / 795mm / 890mm
Magnification	1,03x / 1,02x / 1,02x
Focal Length	644mm / 811mm / 908mm
F-Ratio	7,9 / 7,9 / 7,9
Image Circle (Dia.) *1	44mm / 44mm / 44mm
Peripheral Illumination	89% / 83% / 80%
Lens Elements	2 elements in 1 group
Coating	AS Coating(Over 99,9% light transmission on every single surface)
Dimensions / Weight	Dia.58x x34mm / 111g
Accessory	EX Tube 66(Dia.68mm x76mm, 89g), Spacer Ring SD81(Dia.57.5mm x 22.5mm, 18g)

<SPECIFICATION>

"SD Flattener HD" + "Reducer HD"

Optical Tube	SD81S / SD103S / SD115S
Focal Length	625mm / 795mm / 890mm
Magnification	0,79x / 0,79x / 0,79x
Focal Length	496mm / 624mm / 699mm
F-Ratio	6,1 / 6,1 / 6,1
Image Circle (Dia.) *1	44mm / 44mm / 44mm
Peripheral Illumination	72% / 63% / 60%
Lens Elements	2 elements in 1 group + 2 elements in 2 groups
Coating	AS Coating(Over 99,9% light transmission on every single surface)
Dimensions / Weight	-
Accessory	EX Tube 66(Dia.68mm x76mm, 89g), Spacer Ring SD81(Dia.57.5mm x 22.5mm, 18g)

<SPECIFICATION>

"Reducer HD"

Optical Tube	AX103S / VC200L
Focal Length	825mm / 1800mm
Magnification	0,77x / 0,77x
Focal Length	635mm / 1386mm
F-Ratio	6,2 / 6,9
Image Circle (Dia.) *1	44mm / 36mm *2
Peripheral Illumination	63% / 60%
Lens Elements	2 elements in 2 groups
Coating	AS Coating(Over 99,9% light transmission on every single surface)
Dimensions / Weight	Dia.68mm x 45.2mm, 218g
Accessory	EX Tube 66(Dia.68mm x76mm, 89g), Spacer Ring SD81(Dia.57.5mm x 22.5mm, 18g)

*1 : Over 60% is secured in acceptable image range as well as peripheral illumination. It covers an imaging field of (D)SLR camera of full-format at dia. 44mm and that of APS-C at dia. 28.8mm.

*2 : Dia. 44mm for imaging field (47% at peripheral illumination)

<Features of the SD Flattener HD>

■ Covering entire imaging-field of DSLR with full-format
The kit consists of the high performance flattener lens and connecting rings (Spacer Ring SD81, EX Tube 66) designed for the SD81S, SD103S and SD115S optical tubes.

■ 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.

Photo taken with the SD Flattener HD

<Vixen SD103S>

■ Extraordinary High Contrast

The same anti-reflective AS coatings, which are used for our high-end VSD100F3.8 Astrograph, are 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.

■ Compatible with AX103S and VC200L Optical Tubes.

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. From this reason, the Reducer HD can be used wihtout using the SD Flattener HD. The AX103S covers an imaging field of DSLR camera with full-format sensor with 44mm image circle.

Originally incorporating a flattener lens inside, the VC200L optical tube offers high imaging capability by itself. From 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 DSLR camera with 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 DSLR camera with image circle of dia. 28.8mm with APS-C sensor and dia. 44mm with full-format sensor.

■ Example image with SD103S+SD Flattener HD: M3 Globular Cluster

Full-format and APS-C is a common name for size representing the size of the light receiving plane (imaging sensor or film) of DSLR camera. Full-format (36x24mm), APS-C (23x16mm) and Four Thirds (17.3x13mm) are typical available standard for DSLR cameras. In general, the larger the light receiving plane, the larger the range can be shot.