다카하시 제품의 경우 특이하게 Metal back 이라는 용어를 사용합니다.
말그대로, 플래트너/리듀서 링의 끝에서 부터 거리를 의미하는 것으로, 기존 다른 곳의 distance 개념보다 계산하기 쉬워집니다.
아래엔 없지만 E-180ed 도 56mm 의 metal back distance 를 가지고, 공고롭게도 많은 장비들의 M/B이 56mm 로 나타나네요.
(포터블한 입실론 시리즈들은 다 56mm 입니다. MT160도 리듀서 이용시 56mm)
Takahashi Back Focus Guide for CCD and Photographic Applications
Model - Focal Ratio | Focal length - metal back distance | Reducer F-ratio · focal length · metal back distance | Flattener focal ratio · focal length · metal back distance |
| FC-50 . f/8.0 | 400mm | f/5.8 · 290mm · 55.0mm | n/a |
| FS-60C . f/5.9 | 355mm . 143.9mm | f/4.4 · 264mm · 56.0mm | f/6.2 |
| FC-60E . f/8.3 | 500mm . 173.5mm | f/6.3 · 380mm · 60.7mm | n/a |
| FC-65 . f/7.7 | 500mm | f/5.9 · 380mm · 60.79mm | n/a |
| FCT-76 . f/6.4 | 487mm | f/4.5 · 345mm · 72.8mm | n/a |
| FS-78 . f/8.1 | 630mm . 165.9mm | f/6.1 · 474mm · 72.3mm | n/a |
| FSQ-85ED . f/5.3 | 450mm . 200mm | f/3.86 . 328mm . 72.2mm | f/8.0 . 675mm . 117.5mm |
| FCL90 (SKY-90) . f/5.6 | 500mm . 170.5mm | f/4.5 · 407mm · 72.2mm | same |
| FCT-100 . f/6.4 | 640mm | f/4.6 · 460mm · 76.95mm | n/a |
| FS-102 . f/8 | 820mm . 194.5mm | f/6.0 · 614mm · 83.9mm | n/a |
| FSQ-106 f/5 | 530mm · 120mm | ||
| FSQ-106ED f/5 | 530mm . 178mm | f/3.6 . 385mm . 72.2mm | f/8.0 . 850mm . 117.5mm |
| FC-125 . f/5.6 | 705mm | f/5.9 · 740mm · 134.5mm | n/a |
| FS-128 . f/8.1 | 1040mm . 198.78mm | f/6.0 · 770mm · 83.9mm | n/a |
| FS-128F . f/8.1 | 1040mm . 218.5mm | f/6.0 · 770mm · 106.2mm | f/8.2 · 1055mm · 106.2 |
| FCT-150 . f/7.0 | 1050mm . 309mm | f/5.0· 750mm · 102.45mm | n/a |
| FS-152 . f/8 | 1216mm . 218.5mm | f/6.0 · 774mm · 106.2mm | f/8 · 1223mm · 106.2 |
| BRC-250 f/5 | 1250mm · 106.2mm | n/a | n/a |
| FRC-300 f/7.8 | 2348mm · 106.2mm | f/5.9· 1770mm · 83.7mm | |
| TOA-130 . f/7.7 2.7" focuser | 1000.0mm · 200.0mm | f/5.79 · 780mm · 83.7mm w/TOA Reducer f/5.6 . 728mm . 106.2mm w/Super Reducer | f/7.5 . 980mm . 117.5mm w/TOA-130 FN |
| TOA-130 . f/7.7 4" focuser | 1000.0mm · 200.0mm | f/5.79 · 780mm · 83.7mm w/TOA Reducer f/5.6 . 728mm . 106.2mm w/Super Reducer | f/7.7 . 1000mm . 106.2mm w/TOA-130FF |
| TOA-150 . f/7.33 | 1100mm . 214mm | f/5.7 . 860mm . 106.2mm w/TOA Reducer f/5.5 · 825mm · 106.2mm w/Super Reducer | f/7.3 . 1090mm . 106.2mm w/TOA-130FF |
| TSA-102S f/8.0 | 816mm | f/5.98 · 610mm w/TOA Reducer | f/7.84 . 800mm w/TOA Flattener |
| E-130 . f/3.3 | 430mm · 56.0mm | n/a | |
| E-160 . f/3.3 | 530mm · 56.0mm | n/a | |
| E-200 f/4.0 | 620mm · 59.8mm | n/a | |
| E-210 . f/3.0 | 628mm · 62.8mm | n/a | |
| E-250 . f/3.4 | 854mm · 84.2mm | n/a | |
| E-300 . f/3.8 | 1130mm · 122.0mm | n/a | |
| E-350 . f/3.6 | 1248mm | n/a | |
| M-180 . f/12.0 | 2160mm . 133.0mm | f/9.8· 1763mm · 56.0mm | |
| M-210 . f/11.5 | 2415mm · 162.0mm | f/9.3 · 1961mm · 56.0mm | |
| M-250 . f/12.0 | 3000mm · 150mm | f/9.3· 2328mm · 56.0mm | |
| M-300 . f/11.9 | 3572mm · 107.5mm | f/9.1 . 2739mm . 56.0mm | |
| CN-212 . f/12.4 | 2630mm · 154.0mm | f/9.9 · 2105mm . 56.0mm | |
| CN-212 . f/3.9 | 820mm · 56.0mm | ||
| MT-130 . f/6.1 | 795mm . 91.0mm | f/4.8 · 618mm · 56.0mm | *f/8.2 · 1060mm · 61.0mm |
| MT-160 . f/6.3 | 1000.0mm . 93.0mm | f/4.9 · 776mm · 56.0mm | *f/8.3 · 1330mm · 61.0mm |
| MT-200 . f/6 | 1200.0mm . 87.0mm | f/4.9· 970mm · 56.0mm | *f/8.0 · 1600mm · 61.0mm |
| EXTENDER-Q 1.6X | 125mm | ||
| EXTENDER-TOA 1.6X | 117.5mm |
*Extender/Flattener The metal back distance is measured from the point at which the end of the reducer and the camera adapter come together, hence the name "metal back". Takahashi has measured these distances for optimum performance for photographic or CCD applications. |
